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

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mdgolfguy

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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. 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? Did I properly isolate the indirect tank and is my conclusion on that point valid?

Thanks,

Russ
 
You may have two problems. It could be a bad auto feed. I realize your turning of the valve for the feed should eliminate the pressure from rising but the valve may not be holding.

John
 
my set up is like this: cold water main, shut off valve, backflow preventer, auto feed, shut off valve, expansion tank. If both shut off valves are closed wouldn't that rule a faulty shut off valve out?
 
If you're turning a valve off between the boiler and the expansion boiler pressure will rise when the water is heated. You cannot isolate the expansion tank from the boiler.

John
 
If the expansion tank is undersized it can still hit high pressures when the system is up to temperature. What happens to the pressure when you turn off the boiler-fill valves and the cold feed to the indirect?

You may still have pressure on the indirect from mixer valves elsewhere on the system- open a hot water tap somewhere on the system after turning off it's cold feed, just to rule that out.
 
johnjh2o1 said:
If you're turning a valve off between the boiler and the expansion boiler pressure will rise when the water is heated. You cannot isolate the expansion tank from the boiler.

John
Click to expand...

The valve is before the expansion tank

DSCN0840 - Copy.JPG
 
Dana said:
If the expansion tank is undersized it can still hit high pressures when the system is up to temperature. What happens to the pressure when you turn off the boiler-fill valves and the cold feed to the indirect?

You may still have pressure on the indirect from mixer valves elsewhere on the system- open a hot water tap somewhere on the system after turning off it's cold feed, just to rule that out.
Click to expand...

Expansion tank was fine for a few years.

When the auto feed valve and and the cold feed to the indirect are both closed, the pressure still rises.
 
Some things like shower valves and many single handle faucets can allow backflow, and bypass the water feed to the indirect by feeding into the hot water outlet. So, you may have to turn the water to the house off if you don't have a valve on the outlet of the indirect.
 
jadnashua said:
Some things like shower valves and many single handle faucets can allow backflow, and bypass the water feed to the indirect by feeding into the hot water outlet. So, you may have to turn the water to the house off if you don't have a valve on the outlet of the indirect.
Click to expand...

I have a valve on the hot water line that feeds out of the indirect.
 
Also, I did flush my water heater fairly recently. Not sure if that means anything.
 
With the auto feed off are only two things it can be. The expansion tank is bad or there's a leak in the indirect coil.

Shut off the water feed to the indirect and the auto feed to the boiler. Drop the pressure in the indirect tank to below 12 lbs. fire up the boiler. If the pressure doesn't climb, the indirect coil has a hole in it.

If the pressure still climbs, your expansion tank is bad.
 
Last edited:
Tom Sawyer said:
With the auto feed off are only two things it can be. The expansion tank is bad or there's a leak in the indirect coil.

Shut off the water feed to the indirect and the auto feed to the boiler. Drop the pressure in the indirect tank to below 12 lbs. fire up the boiler. If the pressure doesn't climb, the indirect coil has a hole in it.

If the pressure still climbs, your expansion tank is bad.
Click to expand...

Can I assume you mean, "Firing Up The Boiler" by turning the stat on the Indirect Up to call for Hot Water?
Sounds like I should be performing this test as well.
https://terrylove.com/forums/showth...-Boiler-Pressure-to-increase-pop-of-t-P/page2
 
Fire the boiler up. It makes no difference what calls the burner. There is no tester made that will pinpoint the leak. The boiler already has a pressure gauge on it.
 
Replace the indirect. The pressure won't go much higher in the boiler because you have a very small leak in the indirect coil and the relief valve is leaking it off.
 
Thanks Guys,
New Indirect Installed. Smaller Unit with same volume, Much more efficient. Boiler pressure remaining at 12PSI. Now to completely empty old one to get to supplier for refund.
Again thank you all for your help!
 
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i am a plumber by trade and inventor of the ALL PURPOSE PRESSURE TESTERS & KITS LOUIS GIORDANO
 
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