Amtrol Boilermate leaking water from pressure relief valve

[Brad Anesi]

Amtrol indirect is 30 years old, attached to a relatively new (3 years old) propane-fired boiler. Just yesterday I noticed that a small amount of water was being expelled from the pressure-relief valve on top; it seems to happen just after the boiler shuts off when hot water has been called for. FWIW, to my surprise, the water being spit out was room temperature, not hot. I've experienced this two times now, so it seems to be a repeating problem.

A little more to the back-story... The day prior I noticed I wasn't getting hot water for my shower. I've replaced all the Honeywell zone valves in the past few years EXCEPT this one, so no surprise this one now seemed to be failing. The motor case for the valve was warm to the touch - like perhaps it was continually trying to work. I rapped in it a bit with a hammer and seemed to get it un-stuck and got a batch of hot water made.

I certainly need to replace the valve and I will do that first. Just wondering if there could be any relation between this issue and the tank spouting off. Or do I really have two separate failures going on here?

 

[Reach4]

You know this, but I looked it up your indirect-fired water heater. https://www.amtrol.com/product/boilermate-indirect-fired-water-heaters/

I think that you are saying that the pressure relief valve is on the potable hot-water of the indirect water heater. You should have a thermal expansion tank, and I expect the one you have has failed. So you take a hot shower, and stop using water. Cold water has come it to replace the hot water used. It gets heated, and expands. When the expansion causes the water pressure to get to about 150 PSI, the T&P relief valve leaks water.

Alternatively, you never had a thermal expansion tank, but the water department did some work on your water meter, and added a check valve in the process. If you don't get piped-in city water, and get your water from your own well, say so.

I suggest that you get a garden hose thread water pressure gauge. Widely available, and not expensive. Take a shower, and stop using water (don't flush the toilet, for example). Go look at the gauge. Expect the pressure to be rising until the T&P valve leaks water to relieve the pressure.

 

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[Brad Anesi]

Thanks for the reply. I'm on well water here.

To the best of my knowledge there is only one expansion tank, and that is over by the boiler. Although perhaps the Amtrol Indirect has an expansion tank built in?

Where would I attach the water pressure gauge? To the indirect tank fitting at the bottom?

 

[Reach4]

OK, if the expansion tank is over at the boiler, then maybe the pressure relief valve is for the heating water rather than for the heated water. But maybe not... maybe you could do an experiment or check literature.

It is not unheard of to have a check valve between your well pressure tank and your heated water, it is not common. If there is no check valve in that path, any expansion of the heated water could expand into the pressure tank, so a thermal expansion tank would not be needed for the heated water.

 

[Brad Anesi]

For reference, here's a pic of the tank. Not mine, just found one on-line. But you can see the pressure fitting up top with the pipe that must have been cut off when taken out of service. At least I sure HOPE it was cut off, and not run that way!https://offerup.com/item/detail/330344799

 

[Fitter30]

Here's a install manual they call for a ex tank cold inlet page 4. Look at your boiler water pressure 30 year old cold also be compromised. When replacing the zone valve it would be a good idea to flush the amtrol coil blowing or draining the line added some boiler treatment to the boiler. Replace the 150lb relief valve ,flush the tank after watching a gauge for a day or two on the city water side. If the zone valve failed open the dhw would only be as hot as the boiler water and if it was 150°f you would know it after turning on the dhw. Burn the he!! out of u without a mixing valve.

BoilerMate® - Amtrol

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www.amtrol.com

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[Brad Anesi]

Thanks for the reply. I may have confused things a bit by calling the relief valve a pressure valve. It's the relief valve at the top of the tank that is expelling a bit of water just after the boiler shuts off.

There is an expansion tank plumbed into the system which should be applicable for all zones, including the DHW tank (the 7th zone).

 

[Fitter30]

Ex tank on boiler side doesn't do anything on the dhw side. A t&p valve on top of the amtrol tank is a safety devise and shouldn't be leaking. A gauge on the hot water side will tell u if it's a system problem or bad t&p valve.

 

[Jeff H Young]

looks like a typical Tand p off a water heater , they are pretty common to go bad

 

[Taylorjm]

looks like a typical Tand p off a water heater , they are pretty common to go bad

They are. I have one as well and it's just a t&p valve. I'd replace that first before going crazy and adding other things when it's obviously worked fine for 30 years.

 

[Taylorjm]

I'm not there to check the label on the top of mine, but as long as you get one that's the same temp and pressure settings, just replace that first. It worked for 30 years I wouldn't go through all the expansion tank advice. Obviously if the zone valve needs replacing that's something different and yes, if the zone valve isn't working correctly it can cause excess pressure and temperature because anytime the boiler fires up, it will send heated water to the boilermate. Now this time of year, if it's like mine, the only time the boiler will fire is for the water heater, so even if the zone valve is stuck open, it shouldn't cause excess pressure or temperature, but that should be addressed first, but as Jeff mentioned, the t&p valve on any water heater are known to leak and go bad, so if you got 30 years out of it, I'd replace that first. I tried attaching an image and it's not allowing me for some reason.

 

[Reach4]

I would first monitor the water pressure. If hits about 150 PSI and water comes out of the relief valve, that is normal operation for a temperature and pressure (T&P) relief valve.

 

[Taylorjm]

One other thing to check on. The bottom of my boilermate has a dial for the temperature of the heated water. That sensor will turn the zone valve on or off and will trigger the boiler to fire up. If that sensor is having an issue, it could be heating the water too much. You can check that by simply running the hot water at a faucet and check the temperature of it. When mine is in the normal range, it's actually hotter than I would like. I think it was in the 130* range, so I have to set it a little lower than normal.

 

[Jeff H Young]

150 psi or 210 degrees if its opening at significantly lower figures simply replace valve if those numbers are anywhere close youve got issues to adress example you dont want 100 psi or 160 degrees which are way lower than the t and p should open and you would want to adress both a bad t and p and the other excess

 

[Brad Anesi]

Thanks for all the good input. I will report back.

BTW, the warning on the top of the Amtrol indirect indicates NOT to release pressure via the valve at the bottom of the tank. I presume I should release it via the valve near the zone valve, yes?

 

[Jeff H Young]

there is some controversy but releasing pressure at the Tand p is one way and some people and most manufactures recomend testing it . of cource opening a hot faucet releases pressure. it seems like a partial question what are you attemting to accomplish?