Heating Boiler Repair FAQs

Boiler repair questions & answers

Risks of Having No Working Heat FAQs

Need help understanding heating system in Spain - health risks of no heat?

I don't entirely understand our system as we live in Spain. Our central heat runs off of liquid oil like kerosene. We haven't had heat for several days.

Several technicians have come out and it still doesn't work.

The language barrier makes it difficult to understand and we are relying on our landlord. It sounds as though the furnace is on and running, but there is still no heater air blowing into the house.

My first concern is if there is a potential health risk of fumes and secondly what are possible causes of still having no heat. 2016/02/11 Mary

Reply:

If your heat is by hot water and the boiler runs but you have no heat then a circulator or check valve is not working.

If you have forced air heat then the furnace system must be shut down for safety. No heat can risk frozen pipes, cold, bronchitis.

Boiler Circulator Repair FAQs

Should I move circulator pump to the hot side of the boiler?

I have an American Standard G5 Gas Boiler powering my Hydronic Heating System. There are two hot water lines running out of the top of the boiler - one goes to the expansion tank and the other to the house.

There is a third hot water line on the side of the device that is currently connected to the blow off valve. The pump is on the return side. I plan on updating a few components - valves, expansion tank, air scoop, etc. and I planned on switching the pump to the hot side.

My question is, what are all three outlets and can I cap the expansion tank tube if I put the new expansion tank and pump in line with the line that runs to the house? (Sept 15, 2015) Dan

Reply:

The pump will last longer on the cooler, return side of the boiler. See WHAT GOES WRONG WITH HEATING CIRCULATORS?

and also

See RELIEF VALVES - TP VALVES - home

Should I turn off the circulator pump if my boiler is not working?

I have a boiler that is down and want to know if the circulation pump (multi zone) should be turned off of left on while the system is fixed (2 days)? Any harm either way? On 2017-12-28 by Stevec

Reply by mod: reasons to keep the circulator on - and when to turn it off

Steve, leaving the circulator pump running while the boiler is down may help prevent frozen heating pipes, so I'd prefer to do that.

But if the boiler repair is going to involve opening heating pipes and/or draining the system, of course then you should turn the circulator off to avoid running it dry - that can damage the pump's impeller.

Burnham furnace with 1 circulator pump on feed side and have 4 zones - return pumps don't stop running

I have a burnham furnace with 1 circulator pump on feed side and have 4 zones each with circulater pump on return.

When a zone called for heat return pumps would go on but within 3 min furnace would reach high temp kickout but return pumps would run endlessly with pipes on either side getting warm at best.

Hot wired feed pump and everything is fine.

So would it be the Honeywell l8148e relay or the burnham mixing vs3000 controller that has gone bad (Mar 16, 2016) Bob callanan

Reply:

Good question. Assuming no airbound piping it'd probably be one of the two problems you suggest, or perhaps a stuck flow control check valve. Or a zone valve may have lost power or have a seized motor.

See CHECK VALVES, HEATING SYSTEM

OR the system is air bound. See AIR-BOUND HEATING SYSTEMS - home

First check to see if the feed pump runs on a call for heat, ... without hot wiring it.

Then see ZONE VALVES, HEATING and also ZONE VALVE DIAGNOSTIC FAQ

Bob callanan said:
Ty for the reply but due to living with a wife and three kids, time (showers)was a key factor.

So I grabbed my trusty multi meter and found c1/c2 were not getting power so went with relay being the problem.

Got new 1 installed and every thing is good all in 4 hrs . Not bad for a Piledriver by trade.
As hot as the return circulators got those will probably be next on the list lol

Moderator reply:

Excellent going, Bob. You actually did what many repair techs will do to speed troubleshooting and lower the cost to the client: try replacing the most-suspect part, especially if it's not a costly one. Thanks for the follow-up as that will surely help other readers.

Sometimes we can get a clue that the problem is the relay by

1. visual inspection for burns and arcing

2. hearing buzzing at the relay, or chatter

3. observing that the relay does not pull in when it should

4. DANGEROUS: pressing on the relay to see if by manually closing it the system runs (also risking death by electrocution if you don't know what you're doing)

Circulator pump cuts on and off repeatedly then runs continuously

I would like to know why, when the heating cycle begins, does the circulation pump cut in and out multiple times before running continuously.

It seems to me that the flow of heated water begins once operating temperature is reached and then the pump runs for about 10 seconds and stops before repeating this cycle.

Eventually after about 10 cycles the pump runs continuously.

I suspect the return of cool water to the boiler causes this stop/start cycle until the heated water has completed a circuit of all radiators in the house. I am considering calling someone in but don't want to do this unless these is a fault. - Thanks, Keith On 2017-02-21 by Keith Stamper

by (mod) - circulator has trouble starting = bad relay or bad circulator motor or loose connection

I think something's wrong with your heating system, Keith. Look for a loose or corroded electrical connection in the thermostat wiring.

If your system is typical it's the room thermostat that turns the circulator on or off, not the boiler water temperature.

But your guess makes sense in another vein:

check that the LO on your aquastat is at least 20 degF. below the HI = otherwise cooler boiler temperature will indeed turn off the circulator.

Read more details about those settings at

AQUASTAT HI LO DIFF SETTINGS 

Boiler Leak FAQs

Boiler is leaking water in the fire box

My central boiler is leaking water in the fire box how can I patch it. (Oct 9, 2015) doug said:

Reply:

First you need to know exactly what's leaking; a badly cracked or rusted through boiler needs to be replaced.

There are leak-stop products sold to buy time on a leaky boiler, not something I prefer to use.

Extrol tank/valve is leaking an oil like substance

I Have a hot water heat system -question is on the Extrol tank/valve - the valve is leaking an oil like peoduct. In fact a lot of oil. What should I do? (Jan 16, 2016) Ron

Reply:

Replace the valve or entire assembly; it doesn't contain oil, this is probably dirty heating water. You've got a boiler water leak.

There's water on top of our boiler's burner after heavy rain fall.

Notice water on top of burner after heavy rain fall.

Water looks like it comes down the flue pipe notice splash around area - (Jan 26, 2016) John said:

Reply:

Ask your chimney sweep to inspect and repair the flue, chimney top, or rain cap; check also for surface water leaks into the chimney base if that's above the flue vent connector.

Watch out: what you describe is unsafe.

Boiler Noise FAQs

Heating Boiler Bangs, Rings or makes other odd noises.

Why is our boiler making banging noises?

Our hot water heating boiler is making banging noises.

It's so loud the kids cant sleep. What is going on? (Oct 19, 2015) sally

Reply:

Sally

I'm guessing from your question that the banging noise you cite is occurring in radiators, baseboards, or piping.

To read the causes and cures for this problem

see BANGING HEATING PIPES RADIATORS for noisy hot water or steam heat pipes or radiators that bang or creak

If that is NOT the case, then

see BOILER NOISE SMOKE ODORS - for other oil fired heating equipment that could risk a dangerous puffback explosion

Or for a wider look at possible banging noise sources see BANGING HEATING SYSTEM NOISES - topic home

Banging Noise at oil burner on Camray boiler in mobile home

The problem with my outside wall mounted Camray boiler.

When it is firing now and then it bangs as though the flow of oil stops then starts again. This has only started since having a new storage tank fitted.

Could this be a flow problem. I have had a service engineer out and he has stripped it right down and can find nothing wrong. As I live in a mobile home this has me worried (Mar 25, 2014) Anonymous

Reply:

It should be pretty basic to confirm that oil is flowing; perhaps the tech needs to be on the scene when the banging is happening.

Watch out: be sure to see OIL BURNER SOOT & PUFFBACKS

Safer would be to turn off the heater and call for repair.

We heard a loud bang from hot water heating system

I have a closed system hot water heat. Had a circulation pump installed and i started to get a loud bang in my system every so often.

Tech couldn't figure it out. My boiler was 18 yrs. old and i had it replaced, but I still have that problem. sometimes it makes a slight whistling noise before the band. other times not.

The system has been bled. (Jan 3, 2015) bob e said:

My hot water boiler is banging at 12 pound and above. 25 January 2015 Anonymous

Reply:

Bob

First confirm that the noise is in the water circulating system not the burner itself - the latter can be quite dangerous and may presage a puffback if it's oil or a gas explosion if it's gas fuel and there's a leak or a defective gas control valve.

water hammer can also be the trouble you are experiencing - see inspectapedia.com/plumbing/Water_Hammer_Noise.php

Some modern circulators or zone valves can shut off water rather abruptly.

Anon and Bob:

Anon please see our guide on dealing with banging pipe noises at

inspectapedia.com/heat/Banging_Pipes_Radiators.php

where several types of banging heating pipe noises and causes and cures are discussed.

Watch out: Also see PUFFBACKS, OIL BURNER

Boiler Ringing Noise FAQs

What's causing a high pitched ringing noise at our boiler?

How do you stop the high pitch ringing? (Nov 7, 2015) Henri Desbiens

Reply:

First we need to find its source, Henri.

Then we can understand what's happening and what repair is needed.

So see if you can listen at the heating boiler to get closer to the noise source. Sometimes I use a mechanic's sthethoscope to identify a failing motor or bearing.

So if the noise is at the oil burner motor or a circulator motor, check for a bad motor bearing;

and also see these

OIL BURNER NOISE DIAGNOSTIC FAQs

For a more broad set of boiler noises and their causes also see

OIL BURNER NOISE SMOKE ODORS - topic home,

Boiler Puffback Explosion FAQs

Smoke pours out when our oil fired boiler starts up

I have a home heat by a oil system boiler, and it is making a lot smoke when it goes on. - Anon 10/28/12

Reply: shut off the boiler - beware of a puffback explosion

Anon

Watch out: If your heater smokes at startup it is not operating properly and needs cleaning and service by a professional; I suspect a bad fuel unit shutdown - you are in danger of a puffback explosion, so don't delay.

An explanation of what may be happening and of the risks is

at OIL BURNER SOOT & PUFFBACKS

Boiler troubles following a puffback explosion

Hi we own a home with a hot water/ radiant heat system. It has fin tube heat registers and 7 zones.

We only use 5 zones the other two are for future expansion of the home. We rented this house out and just received it back from our tenant.

Unfortunately we have what looks like smoke damage. It has been suggested that it's puff back from the boiler.

We have had plumbers to inspect the boiler. We have been told we should just replace it at thousands of dollars.

They are unaware of pass back [sic - she means "puffback" - ed] as a real issue. They said it's impossible.

I have found a number of articles that say it's rare but real. I am getting put off by them even after providing copies of articles. Am I wasting my time? Is it real? Thank you 2016/05/24 Diann said:

Reply:

Diann,

Before eating the high cost of replacing a boiler I would want to know the age and condition of the one we have and I would want to know, more accurately, what's wrong with it and what the repair should cost.

A puffback explosion can be caused by simple lack of maintenance, but if the explosion damaged the boiler then yes, it needs to be replaced. Ask the heating company to show you the actual trouble spots.

Be sure you have someone who actually is trained on heating boilers and understands the causes of puffbacks. If your plumbers aren't expert on this problem they may not be the best people to be working on your heating system.

See OIL BURNER SOOT & PUFFBACKS

Watch out: the system could be unsafe.

See also BLEVE EXPLOSIONS

Boiler Heat Exchanger FAQs

Can a cracked heat exchanger cause the boiler to produce soot?

I have a Weil Mclean Gold propane boiler, 19 ys old. Can a cracked heat exchanger CAUSE SOOT FROM THE BOILER? On 2014-03-18 by Renny Scheuerman -

Reply by (mod) - yes; important safety warning

Yes Renny, and

Watch out: the system is particularly unsafe because of the added risk of Carbon Moxide detection. Be sure you have working CO detectors. Obviously the CO risk can be greater for a warm air (forced hot air or "furnace" heating system than for a boiler.

Boiler Airbound, Cold Radiators / Baseboards FAQs

How an I tell if my heating system is air bound or the zone valve isn't opening?

The one zone heats only about 20%. The furnace is also coming on, stops, comes on again, but never reaches the set temperature.

My thermostat was replaced about 15 months ago.

Could it be air in my line or zone valve not opening all the way, or what? On 2014-10-09 by Bob

Reply by (mod) -

Yes Bob. You can try feeling the boiler's hot water piping system and baseboards or radiators to see where the heat stops. That may give a clue to what may be air bound.

Start by turning the heat all the way up at the thermostat.

The zone valve should open, the circulator should start and as cooler water returns to the boiler, eventually the boiler's burner should start.

Feel along the pipes downstream from the zone valve. If the pipe never gets warm and IF the circulator is running, then the zone valve didn't open.

If you feel some heat say 5-10 ft. past the zone valve but the baseboards or radiators never get warm then your system may be airbound.

See details at AIRBOUND HEAT SYSTEM REPAIR

Why does one of our rooms get no heat?

We have hot pipes near the zone valves but no heat at baseboards

Hi my boiler has 2 zones, 1 is for my second floor apartment and the other is for the attic. The pipes past both zone valves are burning hot but the baseboards are not getting hot all. What might be wrong? Can you help? 2016/02/13 Felix

and

Hi, we have a forced hot water system. I'm wondering why, if all of our rooms are in the same zone, one room cannot seem to be heated? - JL 12/26/11

Reply:

Felix and JL:

About having forced hot water heat and one zone or one room not heating, it's possible that the radiators or baseboards in that room or hot water heating pipes anywhere between the boiler and the baseboards or radiators are air-bound.

Start with the diagnosis and repair advice we give at

• AIR-BOUND HEATING SYSTEMS - home

as I suspect that the rads or in your case baseboards or piping to them are air bound

Tell us how to fix an air-bound hot water heating system boiler, piping, radiators, or baseboards

There's noise in the pipe and we drained all the baseboards and the air valves , the thank has 22 psi or air and we still have noise in the pipe , what should I do ? (Dec 7, 2015) Paul Didier

Tell me how to bleed air out of my boiler system - (Oct 26, 2015) Anonymous

Just had a new floor registers replaced in bathroom . should the system be bled of air? (Feb 13, 2016) Ggolden39@verizon.nen said:

Can I bleed 2 zones at once as the eturn lines from the basement and the first floor merge into one down pipe that only has a cutoff valve just before it enters into the boiler.

The drain spigot is located just beyond where the 2 return lines meet and the nearest cutoff valve is the one just before it goes into the boiler some 5 feet down. - Scott

Reply: how to bleed air from a hot water heating system & how to fix an air-bound heating system or a boiler system with air noises

Keep in mind that where radiators or baseboards are piped in a series or "chain", the air blockage will be at or ahead of the first one of those heaters that is cold. So that tells us where to try opening air bleeders first.

The basic procedure is to call for heat, assure the boiler is hot, assure that the circulator pump(s) is (are) running, that the boiler has normal pressure (between 12 and just under 30 psi for a residential hot water heating system), to feel along heating pipes and heating devices to find where the pipes feel cool, and to bleed air beginning close to the "upslope" end of that point.

See complete details at:

• AIR-BOUND HEATING SYSTEMS - home - for an explanation of why heating pipes get airbound and where to look for the problem.
• AIR BOUND RADIANT HEAT - special procedurs for radiant heated floors or slabs.
• AIR BOUND HEAT SYSTEM REPAIR by PUMP - the repair method your heating service tech probably uses
• AIRBOUND HEAT SYSTEM REPAIR by WATER FEED VALVE - an easy step that might work

Paul and Anonymous:

Please see the articles beginning at the first link I give above to see methods to get ALL of the air out of the system piping.

G Golden, yes bleed the air.

Anon: first check that the boiler has working air bleeder(s) installed as those should be doing the job for you. You can also bleed air from air-bound radiators or baseboards using individual bleeder valves.

Scott: whether you can bleed air out of one or two zones at once depends on where the air is located. Usually we need multiple air bleed points to successfully purge all of the air in an airbound heating sytsem.

There is no water in our boiler: tried to purge air but no water comes out

I think there is no water in our boiler's water system. Tried to purge air but no water On 2018-03-04 by Karl

by (mod) - no water in the boiler, water on the floor

Karl:

Watch out: if your heating boiler is empty of water TURN IT OFF IMMEDIATELY and leave it off to avoid damage or unsafe conditions.

Your heating service tech will look for and fix the leak if that's the issue - or repair or replace the water feeder.

Another possibility is that there is water in your boiler but it's cool and hasn't developed enough pressure to push water up to an upper floor baseboard or radiator.

Heating boiler start-up problem FAQs

Boiler rough start, intermittent start-stop

Why does my burnham v 85 hot water boiler start to fire up then stops or fires up and stops very quickly (Nov 1, 2015) nick said:

The boiler's burner flame burns well for a few seconds and stops, and no hot water goes through the pipes and we get no heat.

I already vacuumed off dust from thermostats.

When it worked both thermostats had to be on high to get heat. (Dec 29, 2015) Glenn said:

Reply:

Tere can be several causes of funny start-up, Nick, including a loose electrical wire or thermostat wire, a bad contact between the aquastat sensor and the side of the well into which it's inserted, or a bad primary control; I've also on occasion found improper control settings or a low limit control on an aquastat that could be benefit from being disabled when no tankless coil is installed.

See BOILER OPERATING PROBLEMS - chances are the burner needs cleanign, service, repair, a new nozzle, air bleeding etc. - without more details we won't know exactly what's wrong; even a loose wire can cause the trouble you cite.

Glenn

Is this gas or oil? If gas I suspect maybe a bad thermocouple;

Watch out: If oil heat is used, don't keep pushing the re-start or you may get an puffback explosion.

See BLEVE EXPLOSIONS

(Dec 29, 2015) Anonymous said:
This is a gas flame.

Mod

(Dec 29, 2015) (mod) said:
Try cleaning, adjusting the location of the sensor tip (in the flame) or just replace the thermocouple.

WATCH OUT a mistake can cause burns or a fatal gas explosion.

Hot water boiler blowing steam FAQs

2006 burnham hot water boiler model 206NCL TE 12 basement too hot, steam coming out of boiler

I have a 2006 burnham hot water boiler model 206NCL TE 12 . The problem I have is that it makes the basement like a sauna, I don't see any signs of a leak but you feel the steam coming out just under the electric damper.

It fogs up the basement windows in no time.

I don't hear any thing that sounds like water hitting the flame. Could this be that the boiler has a slight crack in it or is there an adjustment to make? (Nov 15, 2015) Dennis

Reply:

Dannis

If steam is coming out of your hot water boiler then there is definitely a leak that needs to be found and fixed - ask your service tech for help; it may be necessary to remove all of the external jackets to see the leak, but she'll probably also take a quick look first in the combustion chamber. If you're lucky it's repairable.

Watch out: this situation is unsafe.

Our hot water boiler blows steam!

When my boiler has been running for while (~30 minutes) to heat up on a cold morning it suddenly will blow steam and dirty water out of the bottom spigot.

It seems like too much pressure is building up when it is asked to work for a long time? My boiler has 3 release valves. Can these be blocked and cause the pressure to build up? Other thought? Thanks (Nov 18, 2015) Jimmy said:

Reply:

Jimmy

Watch out: "the bottom spigot" ? if you mean the boiler drain this sounds horrible - as if the boiler has run out of water and is about to be destroyed or blow up. Shut if off if you see this, and call for repair.

If there is some obscure leak high on the boiler that runs down inside of a jacket and comes out around the boiler drain that may be a different issue.

A TP valve can certainly become blocked, especially if it has been dripping or leaking over time.

See RELIEF VALVE LEAKS

That case would be extremely dangerous, risking a BLEVE explosion -

see BLEVE EXPLOSIONS to read details.

Oil fired boiler turns on but no hot water leaves the boiler - and steam is coming out of the pressure-temperature relief valve

I have a warmflow bluebird oil fire boiler, where the boiler is firing but no hot water is exiting the boiler, and there is steam coming from the overflow pipe. Does this imply a problem with the internal pump ? - Jason 5/22/12

Reply: shut off the unsafe boiler immediately and call an expert

Jason

Watch out: I would SHUT OFF THE BOILER IMMEDIATELY

and call for a service technician. If the boiler is low on water it could be damaged or worse, unsafe.

Boiler Control FAQs

Neighbor "jump starts boiler" with blown fuse and causes its destruction - lucky it didn't explode!

Dan, got another one for you. After getting the spill switch (etc.) installed and the boiler cleaned, it ran for a week and quit. before my guy could get there, she had a neighbor who is an "engineer" look at it.

He found a burnt fuse, removed it and "jump started" it without replacing.

Now my tenant owes me a furnace, because the safety to keep the boiler from cracking was not in place, and it did. She was lucky it didn't explode, I am told!

Anyway, the quote to replace is for a 237,500 BTU furnace.

This seems ridiculously excessive, and I think they are trying to take advantage of an out-of-state landlord (and, of course, my tenant's insurance and future gas bills).

The house is in the Scranton, PA area, is 2,000 sqf, 2-story, basic insulation (mortar and slat walls, asbestos siding, and appropriate level of insulation for the region in the unheated attic). I am reading anywhere from 50000 BTU to 90000 BTU (lower than my thought of 110000 BTU, actually),

but nowhere can I find anyone saying a two-story residential should have what they are trying to put in there. Is there something I am missing here? (Jan 15, 2016) Steve

Reply:

Wow Steve. Ignorant tenant and idiot Engineer. Good news: nobody died - a possible result of a cracked heat exchanger. Lord protect us from such.

Steve said:

Yeah, that is what I am thinking. Thankfully we require renter's liability insurance.

I did think of one other factor that might affect the BTUs called for - 10' ceilings in the downstairs. But 237,500 still seems overly excessive, isn't it? I don't mind replacing it with what is appropriate, but I don't want folks to have $1000/month heating bills!

Boiler trips circuit breaker - intermittent failure of boiler to turn on

I have a 3 year old Peerless WV-DV boiler, 1 zone (thermostat), 2 circulator pumps, no valves, serviced annually.

This year when turning thermostat up the boiler refused to come on. The 20 amp circuit breaker had tripped. It wouldn't reset, kept tripping immediately. I turned the power switch off at the boiler, reset the breaker, turned the power back on at boiler, turned thermostat up and boiler came on normally.

I then, over the course of an hour, turned thermostat up and down, each time boiler shut off and came back on normally.

Then is got warm here for a few days, didn't use. When it got cold again, same problem, I had to turn off power at boiler, reset breaker, turn power back on at boiler, then boiler works.

I also replaced the breaker in case that was a problem. So what is the issue here? Any help would be appreciated. - Scott Moberg 10/14/11

Reply:

Scott:

It sounds as if there is either a wiring short circuit at a boiler control or at an electric motor (perhaps on the burner) that was seized.

A seized motor can draw high amps and trip the breaker.

You can sometimes get the motor running again by repeated attempts or by adding an electric motor hard start capacitor, but on an oil burner I'd expect it's time to replace the motor.

So we need some onsite diagnosis to find out just which component is causing the overcurrent - though as you can infer, my first bet is a failed motor.

Why did the circuit breaker for my heating system trip off?

One site said that I should call a heating or electrical contractor. Another, that I'd probably have to buy a new system.

Then, there's this one, but the one that finally helped me in an instant was the one that said this: If the thermostat runs from the house's electrical system, check on the circuit breakers.

One of them might have tripped and cut off the power the thermostat. Reset the breaker. THAT DID IT. I NOW HAVE MY HEATING SYSTEM WORKING AGAIN. Now I only have to wonder if I should be worrying about why the circuit breaker tripped. On 2017-11-20 by Warren Jones

by (mod) - look for an electric motor that is seizing or a jammed

Warren,

I would look for an electric motor that is seizing or a jammed coupling or blower fan or a seized fuel unit any of those would easily cause a humming sound from the motor that might sound like it was the Transformer.

Replacement for a Honeywell R8182 D1189 Aquastat?

Can a R8182D1189 be replaced with a moremordern aquastat? (Feb 15, 2016) tayl874@aol.com

Reply:

Yes.

For example, Honeywell usually recommends their AQUASTAT L7224U UNIVERSAL - an example of a universal replacement aquastat.

Where to get aquastat replacement parts

can I get parts for a Aquastat l8148e ? (Dec 9, 2016) randy

Reply:

Randy

Check with your local plumbing and heater supplier. A few sell parts such as a replaceable relay.

But for most people, replacing individual parts in an aquastat control isn't practical nor cost effective.

Usually a service technician installs a whole new control. Beware that modifying a control could make it unsafe.

Try a universal control replacement. See AQUASTAT L7224U UNIVERSAL

What are the correct boiler temperature settings?

What should the temperature be at the boiler mine only reaches 100 then shuts off house is cold (Feb 15, 2016) Mike

Reply:

Mike, normal home heating boiler temperatures run usually between 180 and 200 F at the HIGH limit.

Please see BOILER PRESSURE & TEMPERATURE SETTINGS

Tellme how to turn the water off but keep the heating boiler on

I have a forced hot water system. If i shut the water off at the main, can the heating boiler system still run if I close the shutoff where it feeds into the system? 28 Jan 2015 Scott

Reply:

Scott, you can shut off all water and the boiler will run - presuming this is NOT a steam boiler - that is, it will run just fine AS LONG AS there are NO LEAKS in the entire system.

But

Watch out: A hot water boiler that has a small leak could be ultimately damaged if the burner fires while boiler water is low or lost completely - risking even an explosion and severe damage or injury. Some boilers include a low-water cutoff safety control to protect against this hazard.

But for this reason, while I might leave a hyronic (hot water) heating boiler ON with its water supply turned off, I'd be a bit nervous and I'\d want the system inspected very frequently. I'd be more confident if I knew the system well and was very confident that it had no history of leaks nor signs of likely leakage or other csauses of water loss.

If your boiler is a steam boiler it needs a regular water supply.

If your boiler is a hot water (hydronic) heating system and has a low water cutoff then you can run it with water turned off, risking loss of heat but at least protected from a boiler explosion (as long as the LWCO works).

Otherwise you can more safely keep heat on while turning other water in the building off by making sure that you do not turn off the boiler's water supply.

See details at WINTERIZE - HEAT ON PROCEDURE

Cast Iron Boiler & Radiator Push Nipple FAQs

Do I need to use a sealant on boiler section push nipples

(Mar 28, 2015) Anonymous said:
whe installing nipples back in water jacket do you need to use some kind of sealent on them

Reply: some boiler push nipples require gaskets.

Anon

It depends on the boiler brand, model, design. Some push nipples use gaskets. Tell us your boiler brand and model and we can help find the assembly instructions if you don't have them.

See BOILER LEAKS CORROSION STAINS where we discuss push nipple leaks at sectional cast iron boilers.  

Also see STEAM RADIATOR PIPING CONNECTIONS for radiator push nipple leaks

Radiator push nipple rubber seals leaking

We purchased 12 brand new cast iron radiators and after 5 years all the rubber seals were disintegrating with leaks and white in most all the joints.

We removed, replaced and reinstalled $$$. Now 5 years later all the joints are in worse condition than 5 years ago.

The house had 12 mismatched radiators that we replaced with no sign of leakage or white seal joints.

We just cannot replace seals every 5 years. No specialist in the area seems to know why but all are willing to remove and replace the seals. We have to know why this is happening when it did not happen with the old radiators.

Please advise or refer us to someone in the Indianapolis area that really does know about home boilers and cast iron radiators. Thank you, Linda Hunter Linda Hunter · Apr 6, 2022

Inspectapedia Com Moderator (mod) 

@Linda Hunter,

I agree that what you describe is intolerable and costly. Something is certainly wrong though as I see you realize we can't diagnose it by text.

Even standing on an un-even surface radiators comprised of multiple section bolted together and joined by push nipples don't leak that often and certainly not when new.

I suspect improper seals, or improper installation, such as un-even or improperly-tightened radiator section re-assembly.

I don't have a specific referral. I would talk with the service manager at several hot water (you say it's a boiler - hot water or steam?) radiator or heating companies, ask if they have plumbers/installers with experience with installing and repairing the push-nipple seals on cast iron radiators who might be willing to carefully disassemble one of your rads to diagnose why this problem has been happening and then to fix the trouble properly.

Post some photos of your radiators and closeups of the leak points and of the through bolt assemblies and we might see something on which to comment. (One photo per comment)

Boiler or Furnace Combustion Chamber Damage FAQs

Moved.

See the explanation of combustion chamber liners and reader Q&A about repairing combustion chamber liners now found

at OIL BURNER COMBUSTION CHAMBER LINER INSPECTION & REPAIR