Boiler help - pressure release constantly triggers; no heat

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dfree86

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Hi all - total novice here so bear with me.

I have a 3-zone system with a gas boiler and hot water heater. Have lived in the house for 3 years and each winter have had this problem.

Basically, I'm having to bleed the system using bleed valves regularly and what seems to be happening is some issue surrounding the pressure regulator/feed valve. Here's what happens:

1) Before turning on for winter: bleed from the bleed valve on top floor to get out all air out and make sure there's water all the way up the house.

2) Turn system on and runs well for a few weeks.

3) After a few weeks I notice weak or no heat and check to see that the pressure release valve has been triggering because of built up pressure/air over time.

4) Turn system off completely to let air/water settle.

5) Slowly turn the thread on top of pressure valve to let in water very gradually, wait 30 mins, check bleed valve at top of system to see if enough water has been added to push the air out the top.

6) Repeat. 1/2 turn, 30 mins, check bleed valve, 1/2 turn, 30 mins, check bleed valve. I do this until I get water at the top of the system.

The problem, as I see it, is I'm adding new, raw water all the time and the pressure is SO sensitive that once I get it high enough to get heat to the top of the house - that proves too much pressure over time. Have recently replaced the expansion tank and pressure release valve, so it shouldn't be those.

My plumber father-in-law says it's just a matter of patience and playing with that pressure valve ever so slowly until it's just right. Don't fill the system too fast and don't over-pressurize it. If I'm triggering the pressure release, even after 3-4 weeks of good heat, that means I did something wrong.

What gives here? Am I doomed to play with this thread on the pressure gauge/automatic feeder every winter for the rest of my life. help!
 

voletl

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What is the pressure at the boiler what does it say on the gauge normal pressure should be 12 PSI anything over 30 your relief valve is going to pop
 

dfree86

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What is the pressure at the boiler what does it say on the gauge normal pressure should be 12 PSI anything over 30 your relief valve is going to pop
system has been off for an hour and it's sitting at 10-12

it must be spiking, blowing water out the pressure release, and then not-refeeding? hence no or weak heat?
 

Jeff Handy

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Maybe the circulation pump is going out intermittently, and the water in the boiler is overheating?

If it even has a pump.

Just throwing out an idea.
 

dfree86

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Maybe the circulation pump is going out intermittently, and the water in the boiler is overheating?

If it even has a pump.

Just throwing out an idea.
Pump is about the only thing we haven't replaced, so could be. Appreciate the input.
 

Jeff Handy

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I am not an hvac pro or plumber, and have changed several pumps, pretty easy, just get the same specs and exact physical connections and spacing as the old pump.

Amazon and many sites sell them pretty cheap.

If it turns out you don’t need a new pump now, you will eventually, and now you have it!

Eventually the bearings start getting noisy, then they overheat or die.

Make sure it comes with gaskets, although I had to cut my own gaskets out of high temp red gasket sheets due to weird connections each time.
 

voletl

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My suggestion before you replace anything else is if you're having complications with your water feed replace that
 

fixitron

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It could be a failed expansion tank. Close the valve in the line that feeds water to the boiler. Drain some water from the boiler system until the pressure reads zero (if you can trust the gauge on the boiler). Then use a tire gauge to measure the air pressure on the expansion tank. It should be about 12 psi. If it is much lower then put air in to bring the pressure to 12 psi. If there is water in the air side, replace the expansion tank.
 

Diehard

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In addition to checking out your expansion tank, what have your pressure gauge readings been?

You mention, "checking to see that the pressure release valve has been triggering" and "it must be spiking, blowing water out the pressure release".
Have you seen the pressure release valve release water?
Did you look at your gauge pressure when this happens?
Have you ever seen your pressure gauge above 20 to 25 psi?

So far, a faulty pressure relief valve or PRV(pressure regulating valve) has not been ruled out.

And by the way, failure of a circulator pump does not cause boiler to over heat.
 
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dfree86

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It could be a failed expansion tank. Close the valve in the line that feeds water to the boiler. Drain some water from the boiler system until the pressure reads zero (if you can trust the gauge on the boiler). Then use a tire gauge to measure the air pressure on the expansion tank. It should be about 12 psi. If it is much lower then put air in to bring the pressure to 12 psi. If there is water in the air side, replace the expansion tank.
We just replaced the expansion tank last winter in an effort to correct the same problem. I can't imagine it's gone in a year and replacing the tank (with a brand new, presumably correctly pressurized one) didn't solve the problem. I had also initially thought expansion tank but it seems unlikely
 

dfree86

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In addition to checking out your expansion tank, what have your pressure gauge readings been?

You mention, "checking to see that the pressure release valve has been triggering" and "it must be spiking, blowing water out the pressure release".
Have you seen the pressure release valve release water?
Did you look at your gauge pressure when this happens?
Have you ever seen your pressure gauge above 20 to 25 psi?

So far, a faulty pressure relief valve or PRV(pressure regulating valve) has not been ruled out.

And by the way, failure of a circulator pump does not cause boiler to over heat.
I haven't seen the pressure release valve release water in real time, only seen the puddle of water when I go to the boiler room. This valve was also replaced last year and is thus brand new. I've never seen the gauge go up to 20-25 PSI with my own eyes, only seen the aftermath (puddle of water) and inferred that it must have blown. Whenever I look at the gauge it seems to be sitting in the sweet spot at 10-12 PSI.

I've attached a pic of my pressure regulator/automatic feeder. That thread with the pin in it is what I've been turning down 1/2 turn at a time whenever the heat goes off and I have to refill the system. (Turn off system for an hour, take the pin out, screw down the thread, wait 30 mins to see if it gets water to top bleed valve of system, repeat).

The problem has gotta be air, hasn't it? The reason my heat isn't working or is weak is because of air in the system. Presumably there is some air coming in with the raw water I'm feeding each time. And when I do the above process there is always air at the top of the system that needs to be bled out. Why would it keep happening?
 

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TomFOhio

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Since your boiler pressure is sitting at 10 - 12 lbs I would turn it back on and just make a point to stay and watch the
gauge. If your prv keeps adding water that will put air in the system. You have to get the problem fixed first and then
bleed out the zones to get the air out. If you get up past 20 lbs I would recommend you to replace that pressure reducing
valve.
 

Diehard

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Agree with Tom above.

What was happening to the pressure gauge while you were increasing the pressure setting?
 

dfree86

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Agree with Tom above.

What was happening to the pressure gauge while you were increasing the pressure setting?
I increased it every 20-30 minutes and the pressure on the gauge didn't move. Stayed at 10-12 PSI.
 

dfree86

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Hmmm...one would think that either the pressure gauge is lying or the PRV wasn't doing much.
Some way or another we're getting air in the system OR it's not being eliminated. Maybe the scoop is bad. Maybe there are pockets of air throughout the system (which is weirdly piped, my plumber-in-law tells me). After I filled it with water to the top last night, we had no water up at the top there just this afternoon. So air is getting in and/or not fully leaving when I bleed from the top.

Right now we're looking at installing a Spiro (?) valve to unequivocally eliminate air from the system. I'm not familiar with them, but plumber-in-law tells me it should do the trick of at least insuring the air gets released. Do you think that will work?

May also be the pressure gauge is bad. I could try putting a camera on it to see when it blows.
 

Diehard

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Although I don't believe that's the root of your problem here's some info for ya.

There are a number of automatic air eliminators. Spirotherm Air Eliminators I believe is the one mentioned to you.

Here's a video of it.
 
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Diehard

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I was going to suggest a hose end pressure gauge to allow you to check you pressure. But thinking about it and looking around, I don't think they have a hose end gauge that would be of much use because their range is typically too great to be reading down around 10 to 12 lbs.
I really don't understand how you can feel comfortable changing and/or checking your pressure when you gauge doesn't move.
 

dfree86

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I was going to suggest a hose end pressure gauge to allow you to check you pressure. But thinking about it and looking around, I don't think they have a hose end gauge that would be of much use because their range is typically too great to be reading down around 10 to 12 lbs.
I really don't understand how you can feel comfortable changing and/or checking your pressure when you gauge doesn't move.
You mean from a safety perspective?

Most of today I had a decent sized puddle of water on floor. I assumed release was blowing periodically.

Tonight as I was re-pressurizing the system (screwing down the thread on the pressure regulator) I noticed that the pipe on the release valve was dripping every 5-10 secs, creating the puddle. The pressure release is rated for 30psi and the gauge on boiler was showing 10 psi the entire time it was dripping and while I had the puddle.

Also the pressure regulator is new, went in last winter.

Problem with the gauge?
 
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