Burnham boiler over 30 psi causing relief valve to pop

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  #1  
Old 01-15-21, 02:23 PM
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Burnham boiler over 30 psi causing relief valve to pop

I know I have seen this problem before in many forums, I still cant find an answer to my situation. I noticed my boiler was leaking out of the relief valve a few weeks ago. I replaced the gauge because it was stuck at 12. Now after heat runs for both zones(upstairs and downstairs) the pressure creeps up past 30 psi. The temp is set at 180. I took the expansion tank off and checked the pressure, it is 12 psi. I replaced the auto refill/pressure regulator and also replaced the upstairs zone circulator pump as well as the relief valve. I also bled every baseboard after refilling the boiler. After all of that it still is creeping passed 30 psi. Is the boiler on the way out? Something I am missing?
 

Last edited by artie253; 01-15-21 at 02:44 PM.
  #2  
Old 01-15-21, 03:19 PM
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When you took the expansion tank off, was it empty of water (easy to determine by its weight and lack of sloshing sound when you shake it). The expansion tank is supposed to keep the boiler pressure from getting too high since the hot pressure is always higher than the cold pressure..

If you shut off the autofeed fresh water inlet, does the pressure stop rising so high and also the relief valve stop tripping after a few boiler on and off cycles?
 
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Old 01-15-21, 03:44 PM
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Yes the tank was empty. I'm going to try to shut the refill valve.
 
  #4  
Old 01-16-21, 07:43 AM
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Do you have a domestic hot water coil in your boiler? A leak in that coil could allow domestic water at a higher pressure into the boiler causing its pressure to go above 30 pounds and trigger the relief valve. If you shut off the feed to the coil and the pressure in the boiler does not rise you will have identified the source of the problem. (Obviously you will not have any domestic hot water available during that test.)
 
  #5  
Old 01-16-21, 12:18 PM
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A,
Although both good suggestions and could be possible causes under different circumstances in my opinion neither one of these suggestions is your problemand the reason I say this is.

If you do have a coil and it was leaking into the boiler the coil would act as a leaking faucet and would constantly add water to the system and the relief valve would constantly leak if the boiler was hot or cold and the same would happen if the feed valve leaked by.

You stated that the relief valve only leaked when the boiler water was heated which means that when the water expands when heated it has no place or not enough room to go. You said your tank extrol reads 12 psi when isolated so it seems to be working.

My question is what are your emitters made of. Are you heating up regular finned baseboard and do you have any cast iron rads or cast iron baseboard in the system.
If you have any cast iron rads in your system you need a minimum of an extrol #60 tank instead of the #30 that you most likely have. Simply put, your expansion tank, although working may not be large enough for your needs.

This is just my opinion with the info provided. Hope this helps a little.
 
  #6  
Old 01-16-21, 01:44 PM
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Is it possible the water adding procedure did not work properly? Just throwing that out – I never had to add water and I don’t know think I know how to do it properly myself.
 
  #7  
Old 01-16-21, 02:34 PM
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Z,
It depends what kind of feed valve you have as to how you would add water to raise the pressure. One has a manual lever you lift up, another one has a lever that goes side to side, another has an adjusting screw on top but they all do the same thing. If you leave your manual cold water valve on before the feed valve if the boiler pressure dropped below what the feed valve was set for, usually about 12 psi from the factory then it would automatically feed water to the system by itself.

If you manually close the valve before the feed valve and for some reason lost pressure you would have to open that valve and the feed valve should pressurize the boiler automaticlly but somtimes some sediment get in there and you have to use the fast fill or bypass lever to bring the pressure back up.

Another time you would use the bypass is when bleeding the system to raise the pressure to remove the air. If you have never had to use it you are very lucky because that means that you are running trouble free.

Happy New Year.
 
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Old 01-16-21, 02:36 PM
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Good explanation. Happy New Year!!!!!
 
  #9  
Old 01-16-21, 08:42 PM
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I have a separate water heater for hot water.....not sure if this is related but I just noticed a taco 219 sweat flo check valve...the arrow is pointing in the direction of the boiler and not the zone....is this backwards?
 
  #10  
Old 01-17-21, 07:45 AM
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Do not raise water pressure when venting

Air scoops facilitate separation of air by doubling diameter of flow passage to slower pressure of flow. No magic, just simple physics.

Unfortunately some believe otherwise and say to raise pressure when venting to remove air.

Increasing water pressure reduces air separation and creates new issues.

Here is a detailed explanation of air venting:

https://www.youtube.com/watch?v=CrAUeDaCZVQ

https://www.supplyhouse.com/sh/control/search/~SEARCH_STRING=1"%20air%20scoops?searchText=1"+air+scoops
 

Last edited by doughess; 01-17-21 at 08:07 AM.
  #11  
Old 01-17-21, 09:20 AM
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If the flo check is on the return piping, it should point toward the boiler. It would be unusual to see that configuration but it's possible.
 
  #12  
Old 01-17-21, 11:45 AM
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A,
When you say hot water tank is it a stand alone tank with its own fuel source or is it an aquabooster which is attached to a tankless coil for more hot water storage or is it an Indirect HW tank which is a stand alone tank which has its own fresh cold water source but is heated by the boiler water and acts as a seperate zone off the boiler which means that it has its own pump or zone valve to let boiler water circulate into the tank to heat the domestic hot water.

Since you mentioned a Flocheck I'm guessing you have an Indirect HWH with its own pump. The Flocheck is a directional valve which means it only allows the water to go in 1 direction unless put in the manual position so if you are getting hot water and everything is working it is going in the right direction.

If you still have doubts pics would be helpful to see exactly what you have.

Hope this helps a little.
 
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Old 01-22-21, 07:25 PM
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The expansion tank is only 2 years old, and I checked it by taking it off and checking pressure...right at 12 psi. I replaced the auto refill/pressure regulator(it is also set at 12 psi) , replaced the pressure gauge on the boiler, replaced the pressure relief valve. Flushed out all of the water, let it cool....refilled and bled both zones of air. When I shut the valve at the refill, it seems to hold around 20 psi but after a day , I can start hearing water rushing through the baseboards like it is low on water....could it be steaming off , then refilling? .... I'm obviously trying to avoid a huge bill ... probably have to finally call someone.
 
  #14  
Old 01-23-21, 08:10 AM
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Artie253 “...refilled and bled both zones of air” is no assurance or guarantee of venting.

Draining systems should be avoided. Refilling just brings in new air to vent.

Best way to end venting issues is installing at high points of zones Watts auto vents $8.29 and forget about manual venting.

For $100 put12 Watts on 8 zone system. Haven't manually vented in years.

For more info read Submittal Sheet:

https://www.supplyhouse.com/Watts-05...Vent-3679000-p
 
  #15  
Old 01-23-21, 09:30 AM
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Is your pressure holding at +/- 20 psi? if so, I suspect outgasing:
Anytime cold fresh water is added to a system air or other gasses are dissolved in the water. As the water is heated, those gasses come out of solutiion. It is not uncommon at all to hear "air" after flushing & refilling a cold system. This is especially true with clorinated water or that going thru a water conditioner.
 
  #16  
Old 01-23-21, 12:21 PM
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A,
First off unless you have a monoflo system high vents will not help you and can cause more harm than good. Next, usually if you hear water flowing in your pipes it is a sign of air still in the system.

Although you bled your system it depends how you bled it if all the air is removed and not brought in with fresh waterif not bleeding properly.

In order to bleed correctly you should bleed under high pressure which is 25-28 psi. This is so when you are done no fresh water enters your system, keeping any fresh water and air from entering.

This is my way of bleeding, contrary to another posters advise. I too have 8 zones and have not had air problems since I installed it in 1985 and have NO high vents in the system but I do still have that 100.00 every time I look in my pocket and less parts to replace.
 
  #17  
Old 01-23-21, 03:04 PM
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Auto-Air-Vents release air from where they are placed, regardless of system type.

Increasing air pressure reduces air separetion and can create new issues. Basic theory of air scoopes is increasing area of passage to improve separation.

After venting the space emptied of air is usually filled by opening feed valve to bring in fresh air laden water.

What other posters have not explained is, after “correct venting” what fills that empty space. Maybe hot air?

With auto-air-vents, DH does not have to move furniture and 12 radiator covers to vent. In old age that is well worth a $100. Over 30 plus years, a real bargain.
 
  #18  
Old 01-23-21, 04:08 PM
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"What other posters have not explained is, after “correct venting” what fills that empty space. Maybe hot air?"

If bleeding is done properly there is NO EMPTY SPACE TO FILL. This is apparently where conflicting views surface. I think I finally see what some posters fail to comprehend.
 
  #19  
Old 01-23-21, 06:18 PM
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If bleeding is done properly there is NO EMPTY SPACE TO FILL.
DH finally gets it. Like flushing toilets … afterward you do not have to fill tank. Duh..Duh

But just to be sure, DH periodically checks to see that if auto-air-vents creates space, that water feed regulator fills it and keeps pressure at 12 Psig.

That may not be others "correct" or "proper" way.

DH is not needlessly stressing his 60 year old boiler system with 28 PSIG pressure hoping to vent air at boiler level.

Am old school … air bubbles rise in water.

 
  #20  
Old 01-30-21, 08:03 PM
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I also tried closing the ball valve to the auto fill. When I do that , the pressure seems to stay below 20 psi but water drips from the backflow preventer.
 
 

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