35+ PSI boiler pressure. Have gone through the usual checks.

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Old 05-29-13, 03:35 PM
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35+ PSI boiler pressure. Have gone through the usual checks.

Hey Guys,

I have a Burnham boiler with a Weil McClain indirect WH tank attached to it. I've noticed recently that water has been leaking from the PRV of the boiler and have seen PSI at around 35 at the high point. I've gone through the usual steps:
1) I turned of the boiler and let the pressure hit 0. I read the expansion tank pressure and it was good, at around 12.
2) I reduced the pressure to around 10 and shut off the cold water main to the auto feed valve. Pressure slowly rose over the next few hours
3) I reduced the pressure to around 10 and shut off the cold water main to the indirect tank as well as to autofeed valve. Pressure slowly rose over the next few hours.
4) Aquastat is set at 183. I have though seen it reach 220.

Any idea what is wrong?

Thanks,

Russ
 
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Old 05-29-13, 04:30 PM
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I've gone through the usual steps
There are other things to check: http://www.doityourself.com/forum/bo...sion-tank.html

Chances are your expansion tank is water logged, and lost its air charge. The important question is why?

If your pressure gauge says 35 psig, then either the gauge or the relief valve is wrong. The relief valve should lift at 30 psig.
 
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Old 05-29-13, 04:41 PM
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I have done that. See item 1,
 
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Old 05-29-13, 06:28 PM
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I would say then if the exp tank is good and you eliminated the fill valve..( What type of shut off?)

Then I would say there is a leak in the coil of the indirect. Even though you turned off the water feed to the indirect the heated water is still bulding pressure from expansion... ( I hope that sound right...)

Try doing that and opening a faucet and see what happens.
 
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Old 05-29-13, 06:37 PM
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Well, regardless of whether or not the gauge is accurate, the fact remains that the pressure is slowly climbing... so let's focus on that for now.

My guess based on what you've said so far is that the shutoff on the water feed to the boiler is leaking, AND your pressure reducing valve isn't reducing.

It is less possible that there is a leak in the heat exchanger in the indirect, AND that shutoff valve is leaking as well.

What type of shutoff valves are they?


Unfortunately, you are going to have to 'gamble' a little bit with this one. So start with the safest bet which at this point based on what I've heard so far seems to be the pressure reducing valve and the feed water shutoff valve.

Start there... replace them.

Make sure you FLUSH! and I mean FLUSH! the water line before you install the new reducing valve. Jury rig a hose to the pipe and blow that line out full force to remove any 'crud' in the line... particularly if you are on well water and/or the pipe from the main water line to the boiler is on the long side.
 
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Old 05-29-13, 06:44 PM
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It is still possible that in addition to everything else, you still have a bad expansion tank in spite of the fact that you seem to have 12 PSI in the tank.

We can talk about this part more later...
 
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Old 05-29-13, 07:23 PM
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I also have an additional shut off valve after the PRV. Wouldn't both of them being closed rule this out?
 
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Old 05-29-13, 07:36 PM
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What type of valves? Gate, stop, ball?
 
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Old 05-29-13, 07:43 PM
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They are Ball valves

Also does the boiler have to be below 100 to properly test expansion tank?
 
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Old 05-29-13, 08:36 PM
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Also does the boiler have to be below 100 to properly test expansion tank?



No.. Just all pressure relieved from the boiler. Be careful when refilling a hot boiler though.... You can crack the heat exchanger.

You get any water out the schrader valve? Does the exp tank seem heavy and full of water? Tapping it makes a tinging empty sound?
 
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Old 05-29-13, 09:01 PM
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Nothing coming out of the schraeder valve. Tank does seem empty.

I checked the pressure again a few hours ago when the boiler was about 170 degrees. I relieved pressure in the boiler to 0 and checked the expansion tank which read 9 psi. I went down again just now and the boiler is about 120 degrees and the boiler pressure gauge is reading 15 psi. Is this normal? Should it repressurize when the boiler off?
 
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Old 05-29-13, 09:09 PM
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I went down again just now and the boiler is about 120 degrees and the boiler pressure gauge is reading 15 psi. Is this normal? Should it repressurize when the boiler off?
No...

Water feed to boiler is off?

Is the indirect water feed off? Turn it off and open a hot faucet. Does the psi in the boiler go down?

Take some pics well lit and from different angles. That will help possibly. We will be able to see valves that may be better to isolate things.
 
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Old 05-29-13, 09:34 PM
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Water feed to the boiler is off. I went down again and saw the pressure was again slightly elevated. I drained some water and it was not hot. Here are some pictures of where I drained from and how it connects to the water heater:

If you can't read it, it's a Taco circulator 007-F5
 
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Old 05-29-13, 09:56 PM
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Here are pics of the whole system. Let me know if more or different angles would be appropriate:
 
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