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Water Feeders, Pressure Reducing Valves on Hot Water (Hydronic) Heating Boilers
Automatic boiler water feeder valves
- POST a QUESTION or READ FAQs about heating boiler pressure reducing valves, water feed valves, check valves: operation and repair
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Heating boiler pressure reducer valves - sometimes mis-named as boiler water feeder valves:
Here we explain hot water boiler (hydronic heat) pressure reducing valves and types of manual and automatic water feeder valves used on hot water heating boilers, including when and how to add makeup water to a boiler.
A chart illustrates the adjustment to heating boiler operating pressure as a function of building height or the number of floors in a building being heated.
We include photographs of common pressure reducer valves and water feeders used on hot water heating boilers to aid in product identification, links to installation manuals, safety warnings, installation and pressure reducer / water feeder safety and maintenance tips.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Hydronic (hot water) Heating Boiler Water Feed Valves
The photo above shows a modern automatic pressure-reducing water feeder valve on a hydronic (hot water) heating boiler - one of the safety controls which we discuss in this article.
Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.
[Click to enlarge any image]
Article Series Contents
- WATER FEEDER VALVE, HYDRONIC BOILER - CONTENTS: Water feeder valves & pressure reducing valves on hydronic (hot water) heating boilers - how to install, adjust, maintain, repair
- MANUAL WATER FEEDER VALVES ON HOT WATER BOILERS
- AUTOMATIC WATER FEEDER VALVES ON HOT WATER BOILERS
- AUTOMATIC HEATING SYSTEM AUTOMATIC WATER FEEDER BUILT-IN BACKFLOW PREVENTER
- IS THE B&G PRESSURE REDUCER AN AUTOMATIC WATER FEED VALVE
- ADD A LOW WATER CUTOFF SAFETY VALVE?
- MAKEUP WATER REQUIREMENTS - HYDRONIC HEAT VERSUS STEAM HEATING BOILERS
- PRESSURE REDUCING VALVE (AUTOMATIC WATER FEEDER) HAS TWO ADDITIONAL FEATURES
- PHOTO GUIDE TO HEATING BOILER PRESSURE REDUCING VALVES
- WATER PRESSURE SETTING FOR A PRESSURE-REDUCING VALVE OR WATER FEEDER ON A HOT WATER HEATING SYSTEM
- AUTOMATIC WATER FEEDERS BUILT-INTO EXPANSION TANKS
- PRESSURE REDUCING VALVE TROUBLESHOOTING, INSPECTION, SERVICE & REPAIR PROCEDURE
- PRESSURE REDUCING VALVE (BOILER) CLOG REPAIR
- PRESSURE REDUCING VALVE DISASSEMBLY
- PRESSURE REDUCEING VALVE REPAIR KIT
- PRESSURE REDUCING VALVE WATER FEEDER INSTALLATION
- PRESSURE-REDUCER FAQs
Manual water feeder valves on hot water boilers
Hydronic (hot water boilers) in proper condition do not normally consume any water. Once the boiler and the baseboard, radiator, or convector piping are connected and filled with water, that same water remains in the system indefinitely.
The water in the boiler is heated and circulated through the occupied space to provide heat to the building occupants.
Water may be lost from a hot water heating system, however, due to a small leak that may be un-noticed, or water may be removed from the system during servicing.
Some older heating systems may not have an automatic water feeder and may only provide a manually operated valve to add water to the boiler. To maintain the water level in these heating systems, water can be added from the building water supply piping manually by simply opening a make-up valve.
A manual valve will simply be a shutoff valve that can be opened by hand to force water into the heating boiler.
Automatic water feeder valves on hot water boilers
On many heating boilers
the expansion tank and water feeder valve are separate physical units.
On these older systems the "automatic water feeder" is often a bell-shaped device which opens and sends makeup water into the heating boiler and its piping whenever the heating system's internal water pressure falls below a normal level (perhaps 12 psi when the boiler is cold).
In our photo at left the gold colored bell-shaped device pointed to by the red arrow is an automatic pressure-reducing & water feed valve for a hot water boiler.
An arrow cast into the valve base shows the direction of water flow (from building supply at right into the boiler at left in this photo).
The screw and lock nut on top of this valve permit adjustment of the automatic water feeder valve pressure (it's normally set to 12 psi).
The horizontal lever is a bypass that will send water through the valve on to the boiler at full building pressure (it's normally left "off" in the position shown here).
The separate heating system backflow preventer / check valve indicated by our green arrow in the photo above is discussed in more detail
at BACKFLOW PREVENTER VALVE, HEATING SYS.
Automatic Heating System Automatic Water Feeder Includes Built-In Backflow Preventer
The device to the right of the automatic pressure reducer (water feed valve) in our photo above is a back-flow preventer that is required in some municipalities. The back-flow preventer makes sure that water from inside the heating boiler cannot flow backwards into the building (and community) water supply. This prevents back-contamination of potable water piping from the boiler should the building water pressure fail.
See CHECK VALVES, HEATING SYSTEM for more information about backflow preventers and other heating system check valves.
An automatic water feeder used on hot water heating boilers performs two functions:
Bell & Gossett's sketch of their pressure reducing valve is shown at left.
- The automatic water feed valve reduces the incoming water pressure from the building supply side down to (typically) 12 psi.
That's because the normal in-boiler water pressure, when the heating boiler is cold, is about 12 psi in a normal residential system. A tall building may need to start with higher cold-system water pressure to be able to push hot heating water to upper floors.
[click to enlarge any image] - The water feed valve adds water to the boiler when needed: If water pressure in the heating boiler drops below 12 psi, the water feeder valve will add makeup water to the system automatically, until it reaches 12 psi inside the boiler.
So is the B&G Pressure Reducer an Automatic Water Feed Valve or Not?
Well yes, and no. The valve can automatically feed water into a hot water heating boiler whose pressure falls below the set-pressure (12 psi at factory setting) if the water shutoff valve for the boiler has been left "on".
The B&G pressure reducing valve shown at left includes a bypass lever shown in the "up" or "open" position in the illustration. In this position water is fed into the boiler at street pressure.
When the valve is "down" in the "closed" position, IF the shutoff valve before the pressure reducer is open, water is fed to the boiler if its pressure drops below the valve's pressure setting (adjusted by the lock-nut and screw on the valve top).
But the manufacturer warns that the purpose of the pressure-reducing (and automagic water feeding) valve is to fill heating boilers after installation or servicing. The company says
"It is not a safety device and is not intended to be used as as a water feed valve to control boiler water at a safe operating level".
OPINION: this is interesting since for closed-system hydronic heating boilers (not steam boilers) that's how lots of service techs and inspectors view this device.
In the company's service manual you'll see on the installation piping sketch (edited) for the pressure reducing valve (green, to the right of the blue shutoff valve at the left side of the sketch below) that they expect the installer to include a water shutoff valve (blue at the left end of the sketch below) before this pressure reducer.
Keep the manual water feed shutoff valve closed?
B&G wants you to keep the boiler water supply valve shut except during service - as a precaution that allows easy detection of a boiler leak by noticing the reduced water pressure in that system.
The company also points out that too-frequent feeding of water into a heating system can increase the effects of corrosion and system damage.
In my [DF] opinion, a typical building owner or occupant almost never thinks to check the water level in a hydronic heating system (hot water boiler) until there is some indication of a problem (like no heat or a damaged leaky boiler).
In our experience most hydronic heating boiler installers and service techs leave that shutoff valve "open" or "on" so that the boiler won't be at risk of being ruined or unsafe by operating at low or no-water level - their experience may be similar to mine.
The manufacturer is telling you what's safe in some regards, but they may not have the same view of what people actually do in the field.
Add a low water cutoff safety valve
A safety improvement on hydronic boilers that gets around this argument is to add a low-water cutoff on residential hydronic heating boilers (hot water heating boilers).
That device, always present on steam boilers, is required by local codes in some jurisdictions for hydronic heating boilers too.
See LOW WATER CUTOFF VALVES.
OPINION: on a hot water heating boiler that does not have a low-water cutoff valve installed, we would be reluctant to leave the building unattended for weeks or months during the heating season with the boiler water supply shutoff valve in the closed position.
We would think about leaving the water supply valve open - not what B&G recommends. That way if a small leak develops we're not at risk of destroying the boiler by firing it without adequate water in the system.
This violates the B&G installation instructions for their pressure reducing valve - so be sure to review this concern with your trained, heating service company service manager.
Differences in Makeup Water Requirements - Hydronic Heat versus Steam Heating Boilers
In normal use, a hydronic or hot water heating system does not consume any water. Only if there is a leak (or during service) would the water level in a hot water heating system drop and need replenishment.
That is an abnormal condition, and one that means the system needs to be repaired.
Keep in mind that devices like the B&G Pressure Reducer (notice they don't call it a "water feeder" even though it feeds water to the boiler) is intended for hot water or hydronic heating boilers.
But a hot water heating system might have a tiny, small, even hard-to-find water leak that goes un-noticed for some time, especially if the boiler water supply valve is kept open so that the pressure valve also feeds a little makeup water into the boiler when needed.
Conversely, on a steam heating system the boiler is expected to consume water at every operating cycle - the feed frequency is therefore much greater on a steam boiler and this B&G pressure reducer/water feeder would not be the proper device to use for water feeding.
For water feeders used on steam boilers,
see WATER FEEDER VALVE, STEAM.
The Pressure Reducing Valve (automatic water feeder) has two additional features:
- Pressure Reducing Valve Override: Lifting the lever over the valve body (B&G valve shown at page top) will overcome the 12-psi feature and force water into the heating boiler at building pressure.
This feature is not normally used, but it's useful during some service procedures such as refilling a boiler that has been drained (more rapidly than otherwise) or for temporarily forcing water into a heating boiler at high pressure for diagnostic reasons or to attempt to force air out of an air-bound hot water heating system.
Watch out: forcing cold water into a hot heating boiler can cause it to crack or be ruined.
Keep this "shutoff valve" or override lever closed except during initial filling of the boiler or when manually adding fill to a cool or cold boiler as part of service.
Installing the proper automatic pressure reducer water feeder should prevent this problem by feeding water to the boiler before boiler water pressure (or level if proper controls are added) is too low, and at a slow enough rate.
As B&G puts it NEVER ADD WATER TO AN OVERHEATED BOILER. Failure to follow those instructions could result in serious personal injury or death and property damage.
Watch out: constant addition of fresh makeup water to a heating boiler that is leaking can make discovery of the leak more difficult, and by constantly introducing fresh water, can lead to mineral deposits, clogging, or boiler damage.
Watch out: take a look at the funny lever position on the pressure reducing valve in our photo (above-left). Is it closed, off-bypass (down) or is it partly open (up)? We weren't sure, but this very valve was blamed for a major house flood causing thousands of dollars in damage from mold.
The building was unattended and the valve fed water into the structure for days, resulting in flooding and mold contamination. We wondered if the house-watcher made a mistake or was messing around with this device before the flood.
Watch out: yep one more. The manufacturer warns that
The Bell & Gossett Pressure Reducing Valve is designed for filling hot water boilers and associated piping systems to a properly controlled pressure after boiler installation or system servicing.
It is not a safety device and is not intended to be used as a water feed valve to control boiler water at a safe operating level.
They are factory set at specified limits although adjustment is easily made. They are equipped with a built-in strainer and low inlet pressure check valve. [4] - Pressure Reducing Valve Set-pressure Adjustment: The incoming water pressure setting of 12 psi can be adjusted up or down by the service technician.
The red Armstrong™ pressure reducing valve shown here includes a black plastic cap covering its adjustment screw under the black plastic cap on top of the valve.
You'll see a similar screw (and lock nut) on the B&G water feeder valve in the photos above on this page.
Loosening the lock nut and then turning the screw on the top of the pressure-reducing valve "in" or "clockwise" increases the set pressure of the control. See B&G's "Reducing Valves Installation, Operation, & Service Instructions" linked-to
at REFERENCES below.
Photo Guide to Heating Boiler Pressure Reducing Valves
[Click to enlarge any image]
Our photo at above left shows an Armstrong™ pressure reducing valve. The schematic at above right, courtesy of Carson Dunlop Associates, explains how this pressure reducing valve works.
Our photo (left) shows another model of pressure reducer valve on the water supply line to an Energy Kinetics oil fired heating boiler.
The lever on the top of this valve combines a full-open bypass (when the lever is vertical) and a set-pressure adjusting locknut (below the round lever body).
Safety note: If the pressure reducing valve is combined with a pressure relief valve, for safety these parts must be installed in the correct position.
As Carson Dunlop Associates shows in the sketch above,
and as you'll also see in the B&G installation piping sketch,
the pressure relief valve should always be installed closest to the heating boiler so that it can respond to an overpressure in the heating system.
What is the proper water pressure setting for a pressure-reducing valve or water feeder valve on a Hot Water Heating System?
What is the normal operating pressure of a hot water heating system boiler?
Hydronic heating systems (hot water) typically operate at about 12 psi cold and see a pressure increase to somewhere just under 30 psi when the system is at maximum temperature.
If you set the water feeder pressure too high it's likely that when the boiler heats-up to operating temperature, the water pressure will exceed the safety limit (30 psi) and the boiler relief valve will open to discharge excess pressure and water.
[click to enlarge this or any image]
Because a hydronic heating system's circulator pump has little "lift" capacity (it just pushes the water around the loop of boiler and heating piping and radiators), the heating system depends on its internal water pressure to lift hot water to radiators (baseboards, or convectors) on upper floors in the building.
A higher building may therefore need higher heating system water pressure in order to be able to circulate heat adequately to upper floors.
The sketch, courtesy of Carson Dunlop Associates, explains that a three-story building will need heating system pressure set up to at least 15 psi. when the heating boiler is cold.
But in most cases you should leave the water feeder at the psi set by the installer (typical factory setting is 12 psi) unless the building has unusual conditions (such as more than two stories) that require a higher in-boiler starting water pressure.
Automatic Water Feeders Built-Into Expansion Tanks
An automatic water feeder valve is included as part of some heating system expansion tanks on hydronic heating boilers - in a single unit such as those provided by Amtrol™, Extrol™, Fill-Trol™, or
similar expansion tanks.
The water feeder is the brass assembly found attached to the expansion tank where piping from the boiler enters the tank on these units.
In our photo at left you can see the brass valve on top of the Fill-Trol™ expansion tank and underneath the cast iron air purge valve (red arrow).
The vertical copper pipe is feeding water from the building supply, at building water pressure into the brass valve and through it, upwards into the heating system distribution piping through the silver painted cast iron air purge valve.
This automatic water fill valve is not adjustable by the consumer and is factory-set to add water to the heating boiler whenever the system pressure falls below 12 psi.
The tank below the red arrow is, of course, an expansion tank. We discuss expansion tanks and their troubleshooting or maintenance
at EXPANSION TANKS.
Steam Boiler Water Feeder Valves, Automatic & Manual
Details about automatic water feeders for steam heating boilers are
at WATER FEEDER VALVE, STEAM. Excerpts are just below.
Keeping the proper amount of water in a steam boiler is a critical function for both safety and to avoid damaging the boiler itself. So on a steam boiler we consider the automatic water feeder to serve as a safety device too. Water feed valves on steam heat systems operate under very different requirements than those on hot water (hydronic) heating systems.
Automatic water feed valves on steam boilers (such as the McDonnell & Miller automatic water feeder shown at left) perform functions similar to the valve described earlier for hot water boilers.
Residential steam heating systems are mostly "low pressure" systems operating at less than 2 psi.
In fact if you see the pressure set higher on a residential system it is often an indicator that the occupants/technician have been having trouble getting the steam heat to locations where it's needed.
All steam heat systems all consume some water which escapes from radiator air vents during the time that the steam (heat) is first rising in the building. So unlike a hydronic water feeder, the steam boiler water feeder is going to be much busier, regularly adding makeup water to the steam boiler, but operating at low water pressures.
Steam heating systems without an automatic water feeder are less safe and risk serious boiler damage should boiler water be lost and should there be no low water cutoff installed on the system.
That's why all modern steam heating boilers can be expected to include at least a low water cutoff valve.
Low water cutoff valves are discussed in detail
Pressure Reducing Valve Troubleshooting, Inspection, Service & Repair Procedures
Inspect & Check the Pressure Reducer for Proper Operation, Clean the Strainer if Needed
B&G offers some excellent tips on how to check the pressure reducer for proper operation, and how to fix some common problems.
- Check for corrosion, damage, or leaks at the pressure reducing valve.
Watch out: if you find corrosion, damage, or leaks at the pressure reducer valve, these should be taken as a very serious warning that the valve is about to cause serious damage, leakage, rupture, and unsafe conditions.
This valve should be inspected periodically, in our OPINION [DF] no less than at annual heating system service time. Unsafe heating equipment or controls can cause injury, death, or property damage. - Check to see if the valve is feeding water into the boiler: feel the temperature of the pressure reducer valve body: put your hand on the bell-shaped body of the pressure reducer or on the piping before and after the valve.
If the metal is cold to the touch in those areas, then the valve is "passing water" into the heating boiler.
This should not be happening if at the same time the heating boiler is already up to its operating temperature.
Possible causes:- improper reducing valve pressure setting
- a leak "downstream" from the pressure reducing valve, in the heating system piping or boiler or its controls
- a faulty pressure reducing valve that is not closing when it should - we illustrate this problem
at PRESSURE REDUCING VALVE DISASSEMBLY
Where you will see the strainer on the valve was completely clogged and the valve's internal moving parts were jammed solid. - A tankless coil leaking into the boiler - nothing to do with the pressure reducer
see TANKLESS COIL INTERNAL LEAKS INTO the BOILER
- If the relief valve on the heating boiler periodically leaks or discharges water, on a hydronic heating system (hot water boiler) the expansion tank may be waterlogged - losing the "air cushion" intended to accommodate thermal expansion.
Details offering more thorough diagnostics are
at RELIEF VALVE, TP VALVE, BOILER
and
at RELIEF VALVE, TP VALVE, STEAM BOILER and of course
also
at EXPANSION TANKS.
But one tip for waterlogged expansion tanks that use an internal bladder is one we hand neglected to mention: pump a bit of air into the expansion tank,
then put a dab of water (we recommend spit) on the opening of the air valve found on the bladder-type expansion tank. If the spit bubbles the valve is leaking.
- Check for a clogged strainer in the Pressure Reducer/Feeder Valve
if the pressure reducer will not feed enough water into the boiler to reach the desired cold-pressure setting, before messing with re-adjusting the valve's feed pressure nut and screw, consider that the internal strainer in the valve may have become clogged.
See details about dis-assembling a pressure reducer to remove and clean or replace its strainer
at PRESSURE REDUCING VALVE (BOILER) CLOG REPAIR
Water Pressure-Reducing Feed Valve Inspection Tips
Reader Question: What should we report if finding a water feed valve tied off as shown in this photo?
Tom Sherman - President, Absolute Home Inspection, Inc., 315-673-1755 provided this photo of a tied-off pressure-reducer water-feed valve and asked what we'd say about it, for an ASHI home inspector newsletter.
Home inspectors are expected to be competent to recognize conditions at a home that are improper, unsafe, not functional, etc. provided that the problem or component is readily accessible, visible, and under some other conditions.
In this photo we have a pressure-reducing water feed valve typically used on a hot water or hydronic heating system.
The valve valve, this one is a B&G model, has the job of feeding makeup water to the heating boiler should the water pressure in the heating system fall below the set-pressure on the valve - typically 12 psi for most one or two story residential buildings, though the set pressure may need to be higher in taller structures.
The water feed valve's override lever in the photo has been secured to the water pipe by a black plastic tie.
The override lever is used to put the water feed valve into "bypass mode" by lifting the lever to a 90-degree position above the water piping and valve body - meaning that the valve is manually forced "open" to allow water to enter the heating boiler at whatever pressure is on the inlet side of the valve.
(The heating boiler, not shown here, is always on the outlet side of the valve, and on most of these controls an arrow cast into the valve body indicates the intended direction of water flow.
In our photo we've drawn a blue arrow showing the direction of water flow for this valve. Click the image to see an enlarged version.
If the valve were in manual OPEN mode, the lever would be at right angles to the piping and valve body - its handle would be over the adjustment screw shown in the center of the valve top. So this valve is in the CLOSED position.
Why would someone put a plastic tie on the automatic water feed valve override lever to hold it in the CLOSED position?
Perhaps the heating service technician was annoyed by an owner's emergency service call complaining that the pressure / temperature relief valve was spilling and perhaps the tech found that the owner had been messing with the valve and over-pressurizing the boiler. If you set the boiler water pressure too high when cold then when the boiler heats up the pressure will exceed the (roughly 30 psi) pressure at which the relief valve will open.
But a more likely reason this valve was tied OFF or CLOSED was that it was leaking, feeding excess water pressure to the boiler on its own. One of the failure modes of these valves is that the valve begins to feed water when it should not. That can happen due to dirt and debris in the valve or for other reasons. Someone was trying to force the valve to behave itself.
Functional & Safety Worries with a Bad Behaving Water Feed Valve
Watch out: this is not only an improper heating system operating setup, it is potentially (though subtly) quite dangerous:
- If the valve has to be tied shut because it was feeding water when it shouldn't it needs to be repaired or replaced. But there's more to consider:
- If the boiler has been suffering from overpressure, causing the relief valve to spill frequently, there is a risk that the relief valve will have become clogged with mineral deposits - which in turn can cause the valve to fail to open in a true overpressure or over temperature emergency - the result can be a BLEVE or boiler explosion!
- If the homeowner has been opening this valve, for example during a DIY attempt to correct an air bound heating system, I'd give him or her a good spanking. And if there indeed has been a recurrent problem with the heating system becoming air-bound,
I'd look further for a problem with the automatic air bleed valve(s) that should be found at strategic locations on the boiler itself and perhaps on some sections of baseboards or other heat radiating devices. - If I were the service person, I would replace this water feeder, and I would either satisfy myself about the condition of the pressure / temperature relief valve (including that it has not been spilling) or I'd replace that part as well.
- The maintenance of proper water level and pressure in a hydronic heating boiler and its piping is critical not only for proper delivery of heat to the building, it is also critical to avoid overheating, damage, and unsafe operation should the boiler water level drop too low or be lost entirely.
Watch out: The manufacturers of this type of automagic water feed valve recommend that additional manual control valves be included in the piping system, so in some installations you might also find that the automatic water feeder is not really so automatic.
... the manufacturer warns that the purpose of the pressure-reducing (and automagic water feeding) valve is to fill heating boilers after installation or servicing. The company says
"It is not a safety device and is not intended to be used as as a water feed valve to control boiler water at a safe operating level".
Which is pretty interesting since so many people in the trades as well as among inspectors consider it a safety device.
This article series answers nearly all questions about Heating System Boiler Controls on central heating systems to aid in troubleshooting, inspection, diagnosis, and repairs.
How to Install an Automatic Pressure Reducing Valve / "Water Feeder"
The discussion of how to install a pressure reducer / water feeder has moved
to PRESSURE REDUCING VALVE WATER FEEDER INSTALLATION
The discussion of how to fix a clogged pressure reducing valve has moved
to PRESSURE REDUCING VALVE (BOILER) CLOG REPAIR
...
Continue reading at CHECK VALVES, HEATING SYSTEM or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see WATER FEEDER VALVE / PRESSURE-REDUCER FAQs - questions posted originally at this page
Or see PRESSURE REDUCING VALVE (BOILER) CLOG REPAIR
Or see PRESSURE REDUCING VALVE DISASSEMBLY - internal parts, what clogs.
Or see STEAM BOILER FLOODING REPAIR
Or see WATER FEEDER VALVE, STEAM If your heating system uses a steam boiler
Or see this
Article Series Contents
- PRESSURE REDUCING VALVES
- PRESSURE REDUCING VALVE (BOILER) CLOG REPAIR
- PRESSURE REDUCING VALVE DISASSEMBLY
- PRESSURE REDUCEING VALVE REPAIR KIT
- PRESSURE REDUCING VALVE WATER FEEDER INSTALLATION
- PRESSURE-REDUCER FAQs
Suggested citation for this web page
PRESSURE REDUCING VALVES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.
INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING SYSTEMS
Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia
...
Frequently Asked Questions (FAQs)
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Reader comments, kudos, gripes:
(Oct 27, 2014) Zach said:
Thanks, this was really helpful as I work on my home boiler system.
Question: why do I have to keep adding water to my boiler?
(Jan 16, 2012) Bob said:
why do i have to add water daily to my boiler
Reply:
Bob:
If you are having to add water to your boiler too often either there is a leak somewhere (a condensate line, or hidden in the boiler itself), or steam vents are not closing when they should. Or an automatic water feeder on your system is not working.
Question: expansion tank (or relief valve) keeps discharging water as service water pressure varies
I have a gravity feed system with water radiators in my home. When I leave the incoming water on the pressure in my system goes sky high the expansion tank discharges the water. When my system is full of water and I turn off the incoming water by the water feeder my system loses pressure and I have to add water again thru the water feeder. Is my water feeder the issue?? When the system loses pressure where is that water going?? The expansion tank is above my furnace in my basement. Any help would be appreciated!! Thanks, Fred
In regards to my gravity feed system "pressure" problem question -- Municipal water, system has been working fine for last 15 yrs. When system full of water home heats fine but when furnace off pressure drops. Thanks, Fred
Reply:
Fred,
Particularly with a gravity circulating system, that is you rely on hot water rising through the heating pipes by convection rather than by using a circulator pump, if there is not enough pressure in the heating system hot water may rise too slowly or even not at all to upper floors in the building.
Check the water pressure in your heating boiler (furnaces are hot air systems, water based heating systems are boilers) when the system is cold - for a typical 2 story home you'll want to see 12 psi cold pressure in the boiler.
If your boiler pressure is low and/or if you've had a leak and lost boiler water leading to low pressure AND if your water feeder valve is not working properly (or is not properly set) then you may have low boiler pressure.
Also take a look at "What is the proper water pressure setting for a pressure-reducing valve or water feeder valve on a Hot Water Heating System?" in the article above.
Question: My house is too hot and the boiler circulator keeps going even if I turn down the thermostat
The circulator pump on my Weil Mclain boiler doesn't respond to the thermostat. I closed the manual flow valve to prevent the baseboards from "heating" during the summer. I recently had to open the valve to provide heat to the house now that it has gotten colder but when the house heated up too hot the flow valve would not close and the baseboards continued to receive hot water. How can i "fix" the valve to shut off the water supply to the baseboards? Will i need to purge the water from the zone to replace the valve? - House too hot 12/21/11
Reply:
House too hot:
You're asking a question under an article on automatic water feeders -- valves that maker sure the water in a heating boiler is kept at proper level. This won't help you with a heat control issue.
Under BOILERS HEATING (links at the ARTICLE INDEX the bottom of this article ) you'll
see BOILER CONTROLS & SWITCHES - an article that lists various boiler controls. Your control problem could be in any of several places
- the wall room thermostat -
THERMOSTATS, HEATING / COOLING - the circulator control and relay switch (good guess) -
see Circulator Pumps & Relays - and the flow control valve - which should act as a check valve to prevent hot water from circulating up out of the boiler when you are not calling for heat -
see CHECK VALVES, HEATING SYSTEM.
Fixing the problem by opening and closing the flow-control valve is a stopgap that as you have seen, is not a great solution.
Your system may have two faults:
1. the hot water should not be circulating out of the boiler in summer when you never call for heat - this is a flo control valve problem, presuming that there is some reason that the boiler is hot in the first place (like keeping it hot for making domestic hot water)
2. the circulator not responding to the thermostat - sounds like a circulator relay control problem, presuming that it used to work and that no one changed the wiring.
To replace a flow control valve or some circulator pump assemblies that are plumbed directly in line in the hot water heating system, unless there are isolating shutoff valves before and after the device, you'll need to cool down the system, drain the affected piping, replace the part, and indeed, purge air from the lines to restore heat.
Keep us posted - what you learn will help other readers.
Question: Top floor radiator is not getting water - should I up the system pressure?
I have a home with 3 levels above the basement, and radiators on every floor. The radiator at the very top floor does not seem to even contain water, and bleeding does not help. The radiators on the 2nd floor, just below the attic used to heat up fine, but now they do not seem to have water either. Obviously, there is a pressure issue here, but I had the water feeder valve for my hydronic system replaced just 4 years ago. The radiators in the basement and on the first floor work just fine. Can I turn the pressure screw on the water feeder to increase the pressure while the system has been operating for the past 2 months and the boiler is not cool? - Joey Butters 12/31/11
Reply:
Joey I would NOT start by changing system pressure since there is a good chance that your top floor radiator is simply air bound. Hop over to our radiator troubleshooting articles at RADIATORS and you'll see how to check for and fix an air-bound heating radiator by simply opening an air bleeder.
Question:
i have a three zone ( individual circulator pumps) hydronic system that i recently changed the expansion tank and auto bleeders on and now it wont keep pressure for more than an an hour or so i have searched the system for leaks and cant see any. i have to keep adding water to get pressure back. what else could be wrong and can i leave the make up water valve (not the pressure reducing valve) but the one that feeds it open? is this dangerous?? it is a two story house - Martin Griffin 1/15/12
Reply:
If the system is not maintaining pressure we need to look for a leak or a defective backflow preventer or check valve.
Question: The relief valve at my boiler keeps leaking, even after we replaced it
My boiler has been leaking at the pressure relief valve for 1 week, with the pressure at 30-35 when hot. I drained the steel expansion tank fully, and then re-started the system. The pressure initially was back down around 20, but within 1 day was back up in the 30s and leaking at the PRV. I had a technician come and install a new pressure reducing valve. We all thought that would fix everything.
We drained the expansion tank again before re-starting the system. After we re-started the system, the pressure continued to rise. one day later we're back at 33 PSI and draining from the PRV. I tried draining more water from the expansion tank and closing of the water valve from the city. The pressure in the system went down to 20. After running the heat, it's now hot and at 25 psi. Could I have just gotten a defective new pressure-reducing valve? Any thoughts? Help would be appreciated. - Josh 2/7/12
Reply:
Great question Josh. There are actually several things that can cause the relief valve on a boiler to leak, among them is an automatic water feeder/pressure reducer that is not working properly, but there are quite a few other causes too. The fact that you drained your expansion tank and then found that you could drain it again makes me suspect that as the best starting place.
If it's an older bladderless type expansion tank (some call these compression tanks) it may be that it wasn't adequately drained. If the expansion tank is a newer type that has an internal bladder the bladder may be damaged or the air valve may be leaking out the air charge. Details are at EXPANSION TANKS.
At RELIEF VALVE LEAKS we provide a catalog of all causes of leaks at all types of pressure or pressure / temperature relief valves.
Also see RELIEF VALVE, TP VALVE, BOILER if your boiler is a steam boiler,
or if yours is a hydronic (hot water) system
see RELIEF VALVE, TP VALVE, STEAM BOILER
Question: the water level in my steam boiler keeps rising
my sight glass on manual feed boiler rising without adding water I have steam heat system with
an indirect water heater. - Anon 2/23/12
Reply:
Anonymous:
Your water feeder valve may need repair or replacement. Review the diagnostic text in the article above. This is particularly likely if the boiler level is actually increasing. Don't confuse increased boiler water level with surging when the steam boiler is heating up.
And don't forget to double check that someone else has not manually added water to the boiler.
Question: where do I add water to my furnace
Need to know where I add water to my furnace. The low water indicator is on. Not sure where to look. And not sure if I have an automatic water feeder. Thank you LJV 109/23/11
Reply:
LJV
Indeed finding where to add water to a steam boiler can be tricky for an unfamiliar building owner because the water supply valves are not always located in the same place.
Try backing up a bit: find the cold water supply piping in your home. Follow the piping to the steam boiler.
That route will show you where water enters the boiler as the piping will end either at a manual valve, at an automatic water feeder valve, or at a combination of the two - that is, some boilers may include an automatic water feed valve as well as a manual valve located on a piping loop that pipes around the water feed valve.
In the links listed at the ARTICLE INDEX the bottom of this article , under STEAM HEATING SYSTEMS
be sure to read the following two articles:
LOW WATER CUTOFF CONTROLS
Water Feeder Valves, Steam
Those articles include photos of the valve(s) you are looking for.
Or use the CONTACT link at the ARTICLE INDEX the bottom of this article to send me some sharp, well-lit photos of your system and I'll be glad to look them over and give more specific advice.
Question: is it ok to turn off the water supply to the heating boiler in winter?
(Sept 30, 2014) Anonymous said:
can a hotwater boiler be operated w/out make up for 2 months during cold weather
(Nov 29, 2014) DAN D. said:
Going on vacation for 2 months and wondering if it's OK to shut the cold water supply line to the hydronic water heater. This would still allow all the circulation etc but allows me to shut down the main water supply to our house. This system supplies heat to our lower floor only. I would like to shut the water main off to my house while away. The hydronic heater is separate from the domestic hot water heater. If OK then the heat would still be available but I would not have the potential problem of water leaks from the plumbing system components such as a cracked toilet tank etc.
Thanks for any comments
Reply:
It depends, Anon.
If you mean a steam boiler, almost certainly not - the risk is loss of heat or boiler melt-down or worse.
if it's a hydronic (hot water) heating boiler, maybe, if there are are no leaks. But there too if the boiler leaks it could be destroyed or cause very serious damage to the building if the boiler lose heat or explodes from loss of water. If the boiler has a low water cutoff safety valve (as is installed on all steam boilers) then you'd hav some protection from the latter castrophe.
Dan
I sometimes shut off the water main to a home heated by a boiler but *only* if I am very confident that the system is bullet proof and leakproof - the worry is that a leak in the system can destroy the boiler or even lead to a fire.
If the boiler has a low water cutoff valve on it then you're safe: it will simply shut down if it loses water.
Otherwise I would leave water on to the boiler.
In some buildings it's possible to leave the water supply on to the boiler but to shut off all of the hot and cold water supply piping to the rest of the house. That reduces the freeze-burst-pipe damage risk substantially and is worth doing.
Dan see this recent article we put together on this at
WATER TURN OFF? - see inspectapedia.com/plumbing/Winterize_Turn_Water_Off.php
More details about this topic are at our WINTERIZE HEAT ON article found at inspectapedia.com/plumbing/Winterize_Heat_On.php
Question: What valves do I need on my boiler: why do I have no heat in half of my baseboards?
(Nov 18, 2014) Jeqal said:
I have a boiler with two spigots and two silver valves. How do I know which one is the drain and which line the two valves go to? The copper pipe is in a circle at the boiler and one of the handles is at the top and one is upside down on the bottom (the valve is a circular dial style handle). I am not receiving heat to half of my base board heat. Do I need to turn one or the other valves? How can I check it?
Reply:
Jeqal
From just your note, I don't know what valves you are referring to.
Check that each room thermostat for each heating zone is calling for heat - set the thermostat well above room temperatures.
Then check that the boiler is circulating hot water in each heating zones - touch or feel (with care) for hot pipes at each circulator or zone valve.
There could be a thermostat, zone valve, check valve, or even an air bound heating system problem.
It's time to call your heating service technician.
Question: Munchkin t50 boiler with pex tubing - do I need a mixer valve?
(Nov 24, 2014) Mike said:
Im running a Munchkin t50 boiler with 1800 feet 1/2" Pex tubing in a slab. Do I need to have a mixing valve or should I use a closely separated tees setup?
Reply:
Mike am not expert on radiant heat slab systems that do not use a mixing valve to keep the water temperature at the required level and to avoid overheating. However there are some modern hydronic heating boilers that include sophisticated controls to adjust boiler temperature to work with radiant floor heating. Those systems may omit a separate mixing valve.
Have you asked a heating design engineer for help with your system to be sure it will meet its requirements?
In any event a water feed valve as discussed in the article above is completely separate from the mixing valve used to maintain radiant heat system temperature.
See inspectapedia.com/heat/Radiant-Slab-Heat-Mistakes.php
Question: how do I know if a water feed valve or TP relief valve is bad?
31 Jan 2015 Anonymous said:
How do I know the feed valve or relirf valve are bad or replace both the relief valve is letting water out. I have a new expansion tank
Reply:
Anon
If you are seeing leaks from the water feeder valve chances are it needs repair or replacement; some water feeders can be repaired using a re-build kit.
But
Watch out: when you also cite that the relief valve is leaking that suggest that either the heating system is at too high a pressure or temperature (unsafe conditions that deserve a system shut-down) or the leaks could be caused by a water-hammer problem at the building or high water pressure or both.
First see RELIEF VALVE LEAKS
then
See WATER HAMMER NOISE DIAGNOSE & CURE
Question: normal input pressures
(Feb 12, 2015) Anonymous said:
my psi rteads 40 on water inlet gauge. is this too high
Reply:
40 psi is within normal building water supply service pressure ranges.
About water pressure: 40 psi on the street side of the pressure reducer/water feeder valve side of a feed valve for a boiler is ok.
Watch out: But if you are seeing 40 psi on the boiler side, such as on the boiler's gauge, something's wrong and if that's really the pressure you should shut down the system as it is unsafe.
Question: can't get water to boiler after flush-out
(Feb 24, 2015) Anonymous said:
I shut down boiler and flushed it . When I turned it back on not getting water to boiler
Reply:
Anon
Check for a debris-clogged fill valve. Try lifting the valve bypass lever to see if that sends water to the boiler.
Question: recurrent air blocked radiators, low psi water feeder
16 March 2015 Tony said:
I have a issue with my 4 story building in NYC, top floor, 4floor, (2) apartments have alot of air trapped in the radiator. I installed auto vent valves and still not helping. I force water thru the auto water feeder and that forces the air out of the line and it is fine for a few days. Then air gets trapped again.
I have to force water every 3-5 days during this winter. I believe that my water feeder psi is set at 15 psi. I don't believe it is enough pressure. Based on your input, I may need a different type of auto water feeder, more for commercial. Every winter we have this issue and not sure what to do next. I tried to get multiple plumbers to look into this matter and they have no idea. Based on your carlson dunlop diagram, I need 20-30 psi pressure for a 4 story building. Please advise it will be greatly appreciated.
Reply:
Tony, what you say sounds reasonable to me. If you are seeing recurrent air blockage in all of the radiators of both top floor apartments that strengthens the argument.
What does your heating service company technician say about the water pressure settings?
...
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Technical Reviewers & References
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- [1] Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects" section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and home inspection educator.
- [3] B&G Flo-Control Valves - installation, operation, and service instructions manual - original source Bell & Gossett, 8200 N. Austin Ave., Morton Grove IL 60053, USA - Tel 847 966-3700 Fax 847 965-8379 . www.bellgossett.com/BG-Literature-Detail.asp?LiteratureID=607
- [4] B&G / ITT Reducing Valves, Instruction Manual V55999: Reducing Valves Installation, Operation, & Service Instructions, Bell & Gossett Air Separators and other heating system components, Bell & Gossett, 8200 N. Austin Ave., Morton Grove IL 60053, USA - Tel 847 966-3700 Fax 847 965-8379. Original source www.bellgossett.com/literature/files/610.pdf
- Fuel Oil & Oil Heating Magazine, 3621 Hill Rd., Parsippany, NJ 07054, 973-331-9545
- Domestic and Commercial Oil Burners, Charles H. Burkhardt, McGraw Hill Book Company, New York 3rd Ed 1969.
- National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
- The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update,
- Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
- The Lost Art of Steam Heating, Dan Holohan, 516-579-3046 FAX
- Principles of Steam Heating, Dan Holohan, technical editor of Fuel Oil and Oil Heat magazine, 389 Passaic Ave., Fairfield, NJ 07004 ($12.+1.25 postage/handling).
- "Residential Steam Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
- "Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
- "Warm Air Heating Systems". Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
- Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals,
- Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Macmillan Publishing Co., NY
- Installation Guide for Residential Hydronic Heating Systems
- Installation Guide #200, The Hydronics Institute, 35 Russo Place, Berkeley Heights, NJ 07922
- The ABC's of Retention Head Oil Burners, National Association of Oil Heat Service Managers, TM 115, National Old Timers' Association of the Energy Industry, PO Box 168, Mineola, NY 11501. (Excellent tips on spotting problems on oil-fired heating equipment. Booklet.)
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
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