Steam heat control FAQs

This articler series includes a photo guide to all types of controls found on residential & light commercial steam heating systems. This article series provides an illustrated inspection and repair guide to Steam Heating Systems.

The page top photo shows a modern steam heating boiler.

Q&A on Controls Found on Residential Steam Heating Systems

These questions and answers about identifying, fixing, or replacing controls on steam boilers or steam heating systems were posted originally at STEAM HEATING SYSTEMS & CONTROLS - home. Please check out that index to articles on each steam heating control and component.

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On 2018-03-09 22:04:08.853623 by (mod) - high pitched whirling noise from steam boiler

Brenda

I would be looking for hissing at a steam valve first.

A very high pitched noise might come from a motor bearing that's failing but on a steam boiler I'm not sure where such a motor would be in use

- perhaps a condensate pump or a hot water circulator if the system also uses its water for hot water or hydronic heating in a low building area.

See HEATING SYSTEM NOISE DIAGNOSIS for a catalog of heating system noise sources, causes, cures

On 2018-03-09 by Brenda

We hear a high pitched whirling noise which seems to come from the steam heat system.

We are hearing it more frequently and can't figure out what part of the system is causing it.

On 2018-01-03 by (mod) - purpose of the steam boiler syphon gauge (siphon gauge)

Jay

A steam boiler siphon gauge (some sources spell it syphon gauge) or snubber attempts to stabilise the boiler pressure gauge and thus the accuracy of its readout by a small piping loop that reduces the effect on the gauge of boiler surging or pulsation.

Particularly because residential steam boiler operate at very low pressure, under 1 psi, the siphon helps stabilize the gauge that hs to operate in a low pressure range.

I attach a steam boiler siphon gauge siphon tube photo from Glival.

On 2018-01-03 01:08:26.443648 by Jay

What does internal syphon gauge do?

On 2017-12-30 00:48:10.375211 by (mod) -

Tia,

I don't know for sure and I will do some further research, but I speculate that the error messages telling you that the thermostat is not correctly wired. For example it may be that two thermostat wires are shorted together.

On 2017-12-29 05:10:45.066931 by Tia

What does it mean when the digital thermostat box says hardwired please call for assistance??

On 2017-12-16 21:40:42.844824 by (mod) -

Karen,

In a one-pipe steam system the individual radiator valve only controls the entry of steam into that radiator (and the exit of condensate out of that radiator back into the one-pipe system).

The exact purpose of the valve at an individual radiator is to permit the occupants to turn the radiator down, reducing its rate of heating, or to turn it off completely.

On 2017-12-16 21:15:54.150878 by Karen Rose

We have a one pipe steam boiler system in a 12 unit building. The valve connecting the steam pipes to the radiators - is that part of the overall system? Need to clarify further if the valve is only for the specific unit in which it is located, or if it helps to regulate the whole system including the units above or below? What is its exact purpose? Your help is required, please. My email is luvrozs@gmail.com. Thank you very much for your assistance.

On 2017-10-26 14:56:27.118649 by (mod) -

Is this a steam boiler? If so it has a manual or automatic water feed valve or both. If that valve isn't working properly that could be the problem.

Does the boiler include a tankless coil? If so and if that's leaking into the boiler that too would be adding water. Search InspectApedia for TANKLESS COIL LEAKS INTO BOILER to see details

On 2017-10-26 13:44:31.882557 by Lou

The water level in my furnace is to high. We tried drawing but level won't come down. Is there another valve we should be looking for?

On 2016-12-29 01:23:48.049312 by miguel

i have 9 radiators , the only time they all heat up is when i first turn on the boiler....then throughout the day when the boiler kicks on again only like 1 or 2 sections of like 4 or 5 radiators gets hot...i gotta keep it at 76 degrees to get sum warmth but yet still feel cold because it cools down quick....

On 2016-12-10 by (mod) -

Need

Low water cutoff controls or LWCOs are standard parts produced by several large manufacturers - they are not specific to a boiler brand. Check with your local heating service company or local heating suppliers.

On 2016-12-10 by Need a low water cut off for a crown boiler

Need a low water cut off for a steam crown boiler.

On 2016-09-03 19:15:40.427398 by (mod) -

Eileen:

The "Hartford loop" is a loop in the condensate return piping (that means water coming back to the boiler from radiators) in a steam heating system. It's a useful safety feature as we detail at HARTFORD LOOP https://inspectapedia.com/heat/Hartford_Loop.php
as it protects from loss of water out of the boiler should the condensate line piping spring a leak.

A modern steam boiler ought also to have a low water cutoff control and probably an automagic water feeder to keep water in the boiler, but while those might keep the boiler running if there's a leak we still don't want water to leak out of the boiler itself.

There MIGHT be piping arrangements combined with safety controls that some steam boiler manufacturers accept.
Take a look at the data tag on your steam boiler. Make a note of the boiler manufacturer and the boiler model and serial number.
Then give the manufacturer a call to ask this question. Let me know what they say.

(Use the page bottom CONTACT link to send us photos of your boiler and its piping and its data tag if you like and we an comment further)

On 2016-08-31 15:15:58.798869 by Eileen

An inspection has revealed my burner (installed in 2014) does not have a Hartford Loop, and one should be installed. Can you give me s ballpark figure for cost of installation?

On 2016-03-11 23:08:49.109025 by (mod) -

Thank you for the nice remarks, Engnr. Rana. Particularly from a professional engineer it's encouraging praise. We also much welcome critique, questions, content suggestions and are happy to credit content-conrtibutors.

Daniel

On 2016-03-11 08:13:19.981608 by Engr Rana Khawar Hussain Khan

Above mentioned article is most important and informative . I think it could helpful for concerning person.

On 2015-12-10 07:56:13.004843 by (mod) -

Did you try the advice at our article on BANGING RADIATORS AND PIPES?

On 2015-12-09 17:42:30.123564 by carlos

i check all the valves, i made sure radiators are slope the proper way, i made sure there is water in the boiler , but i still get the banging. Do i need to drain the boiler. i think there is water in the lines but do not know how to drain it. Please explain if possible.

On 2015-11-09 21:08:03.111609 by (mod) -

Alan it sounds like time for a service call: the number of snafus that can cause the unit to shut down is a bit long to speculate upon with no more data about your system.

Or if you like, see the diagnostic flowchart at OIL BURNER WONT RUN https://inspectapedia.com/heat/Oil_Burner_Wont_Run.php as that's quite complete.

On 2015-11-09 12:56:19.787906 by Alan

My steam by oil furnace runs for 3-5 minutes before shutting off, then restarts in about 10 minutes. Any help?

Question: steam pipe configuration question at the boiler

what's the term they call the 2 steam pipes that form an H above a steam boiler. in other words the pipes from both sides of the burner connected together?THANKS,Walter - 9/25/11

Reply: steam pipe header

Walter: sorry we couldn't give an instant reply; sometimes the volume of reader questions is considerable and takes some time to get thorough.

I am guessing you are referring to the steam header or manifold piping that allows steam to enter more than one steam supply line or riser.

A second piping configuration that will be along side, not above, the boiler is the Hartford loop - a loop of piping sort of like an upside down trap that prevents water from siphoning out of the boiler should there be a leak in the condensate return line.

Question: steam boiler parts identification

Wow, what a great web site. I am trying to identify a vessel on the side of an old National steam boiler/furnace. It is about 12-18" tall, about 8" diameter and is attached to a manifold in the side that is about 12" off the floor. It is heavily rusted. The boiler is an old coal fired converted to oil. Can I send you photos? Thanks, Stephen strentsch@yahoo.com or strentsch 10/4/11

Reply:

sure Mr. Strentsch,

use the CONTACT link found at page top, left, or bottom to see our email and send along some sharp photos and we'll be glad to take a look

Question: My steam boiler seems to be taking more water than usual

I blow the system down regularly and then make up the water in the sight glass. However I seem to be using significantly more water then years past whereas I'd top the sight glass every couple of weeks in the past compared to every other day now. What do you think the problem is? - Tom C 10.27.11

Reply:

Tom C: a common reason for increased water consumption in a steam heating system is one or more radiator steam vents that are not closing properly. Check also for a leak in the condensate return line.

Question: I need to prepare for a steam boiler license and want book recommendations

I’m happy to have found this website. I’m getting back into heating and cooling and need to prepare for higher license. Question: Is there a DVD collection you recommended as an additional studying tool? I see that Harold J. Frost, Frederick M. Steingress, Daryl R. Walker’s collection is close to 600.00 which is very steep for my pocket. Would you happen to know of a website or cheap place I can buy such DVD or a CD? If not these guys than another author is ok. Thanks for the feedback. Kym 11/23/11

Reply:

Kym if you are looking specifically for information on steam heating I'd pick up any of Dan Holihan's books on steam heat. He's the best.

Question:

The HomeServ tech just left after installing a new auto water feeder, and the PSI gauge on my steam heater is off the chart, over 30 PSI. I shut it down and called HomeServ and they said leave it on and they'll come in the morning. How do I lower the PSI myself so I can leave it on tonight and my little kids (two with strep) don't freeze? Thanks! 2/22/2012

Reply:

Watch out: If the PSI gauge is showing abnormal pressure and the gauge itself is working properly the system is unsafe and should be shut down. Call someone else and fire that tech - from your description the system sounds unsafe

Question: water drips out of the air valve at the bottom of the tank

I HAVE AN OIL BURNER HOT WATER SYSTEM MY EXPANSION IS DRIPPING WATER OUT THE AIR VALVE STEM AT THE BOTTOM OF THE TANK SHOULD I REPAIR OR REPLACE - Mike S 10/12/12

Reply:

Mike, an air valve stem is replaceable, I would tr that first. Check also for abnormal system pressure ( an unsafe condition). But if the internal bladder of the tank has burst - another explanation for finding water at the air pressure adjustment valve, then most likely you need to replace the tank. You'll know this condition because the tank will become waterlogged, heavy, and ultimately the boiler TP valve will drip (another unsafe condition).

Question: radiator banging noise repair procedure

I have a one pipe steam system. My dining room radiator air vent was just replaced because the old one was leaking profusely (damaged my floors). The porch radiator air vent was also replaced because of too much steam condensation in the room, but now the open/close valve is leaking at the base. The radiator upstairs in middle bedroom is banging and clanking. The pipe that runs along the basement ceiling (finished basement) also bangs when the heat is coming on. My plumber cannot really give me an answer. Any suggestions would be appreciated. Thanks p Rita 11/21/12

Reply:

Rita,

If you search InspectApedia for

BANGING STEAM PIPES

you can read about the diagnosis & cure of this problem

About the leaking valve - unfortunately that means you need another service call.

Question: relief valve is leaking

cleaned on a vav [?] system is leaking close the cilanod [solenoid ? -Ed] valve need to be replaced

- Anon 11/23/12

Reply:

See RELIEF VALVE LEAKS for procedures to diagnose and fix leaky TP relief valves.

Question: trouble controlling level of steam heat - can I close off the radiator

My building uses steam heaters. I have no control over the heat in my unit because the thermostat is controlled by my landlord/owner who lives above me. However I have a small 1 bedroom with two heating units so even with all of the windows open, it can still get very hot. Is it okay for me to completely close the "open/close" black knob valves on my units or will that cause problems for the whole system? My landlord had previously told me not to touch the valves... Emily 12/10/12

Reply:

Yes if the radiator control knob is not jammed or frozen you can try closing it partly or fully; radiator control knobs are intended to be a homeowner-resident-operator control. But if the knob is not easy to turn, don't force it as you might end up with a leak.

Question: hissing boiler

I have 2 yr. Boiler. It hisses like venting steam off and on loudly. Seems like when heat comes on venting starts until off. -Mr. Ed 12/28/12

Reply:

Steam boilers include steam valves that hiss; we need more details.

Question: leaky relief valve

I am having a pressure problem and it looks like one of my relief valve is leaking or letting the pressure out would this keep my boiler from running. It seems to be shutting off and I need to set the pressure all the time. is it as simple as changing the valve and resetting the Pressure? Rick 1/3/2013

Reply:

See RELIEF VALVE LEAKS for procedures to diagnose and fix leaky TP relief valves.

Question: steam boiler stopped working

(Mar 23, 2013) home able said:
Oil-fired steam boiler was functioning properly upto two weeks ago, now doesn't fully run to designated temperature on thermostat (digital). It will stop a degree or 2 short of desired setting even though thermostat says boiler is running. Why?

Reply:

Home able,

I'm not sure what's happening with your system. IN general the gauges are not lab grade precise. It's possible that your gauge or its sensor port are debris clogged. Try tapping gently on the gauge to see if the needle moves. Also watch the gauge to see its reading throughout the operating cycle.

Question:

(june 19, 2014) anonymous said:
I have hot water baseboard system boiler in my crawlspace (.Basement) im thinking about replacing the boiler with a horizontal warm air furnace adams furnace. I keep getting freezeups and they are very difficult to repair. The furnace adams make is supposed to be 95 percent efficient. Plus the fact there are no pipes to freeze is the warm air furnace the way to go? Thanks paul

Reply:

Paul,

You're commenting about hot water and hot air heat on a steam heat article - so this may be a bit confusing to other readers, but in general, conversion to another heating method is fine if you can bear the expense; each heating type has its pros and cons so IMO there is not a single "right" answer. Keep in mind that when you change from steam heat or hot water heat to forced warm air heat, your costs are much greater than just the heater itself as you have to install a heat delivery system : air ducts and registers. That can be convenient in some building designs and quite costly in others.

Question: pressuretrol settings for second floor in an office buildings

(Oct 16, 2014) Antonio said:
I just installed a 299 MBH gas fired steam boiler and connected to an existing system serving the second floor of an office building, approx floor area is 2,600 sq ft.
Existing EDR calculated as approx 900 sq. ft. The boiler started up successfully yesterday and I have been testing it ever since. Everything seems to be working fine. My question is what would be the right pressuretrol settings: I am using 1 psi cut-in and 1 psi differential and everything seems all right, but I may be missing something, maybe the boiler could work more efficiently with a lower or higher cut in pressure.

(Dec 15, 2014) Kevin M said:
I have a gas-fired steam boiler that has worked flawlessly since its installation six years ago. Suddenly it is overfilling. I let out several extra gallons a day to reduce the level in the sight glass. Shoudl I replace the automatic feed? It is attached to the hot water heater, unlike previous installation I have had in othe rhouses where it is connected to the cold water line. I sit possible that excess pressure from the expansion in the hot water supply line is forcing water past the automatioc feed? What could cuase this condition?

Reply:

Kevin

Over-filling of a heating boiler is indeed usually a problem with the automatic water feeder, more rarely leaks into the boiler from a tankless coil.

Question: bothered by banging pipes

(Feb 15, 2015) Bevery Streeter said:
I live in a 16 unit apt complex. What make the heat clan and banging?

Reply:

See the banging pipe diagnostic and repair suggestions at BANGING HEATING PIPES RADIATORS

Question: steam boiler won't keep running

(Apr 9, 2015) george said:
steam boiler heater runs for about 15 minutes then it cuts out

Reply:

George I'm stuck on this one with no onsite data; could be related to heating of components, clogging of a filter, I dunno. It's time for an onsite heating service tech.

DO NOT keep pushing a re-set button. That's unsafe.

 

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Recommended Articles

• COLD STEAM HEAT RADIATORS - diagnose & repair
• WATER FEEDER VALVE, STEAM

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