Boiler, Leaking pressure relief valve

[Reach4]

I just changed the pressure relief valve, and so far everything's looking good. Fingers crossed. It must have been the excess pressure in the ET for all this time that kept wrecking the pressure relief valves. Simple, in hindsight.

I think you might want to clarify that you are talking about your boiler system, rather than a relief valve for a water heater. Or maybe you are talking about the water heater?

 

[BobD777]

I think you might want to clarify that you are talking about your boiler system, rather than a relief valve for a water heater. Or maybe you are talking about the water heater?

Hey Reach-- I was indeed talking about the relief valve for my boiler system. As it turns out, I ended up changing the pressure relief valve, which had been leaking for a while. Thinking that was caused by an overcharged expansion tank. So far so good. Let's see how it performs over the next week.

 

[Sponsor]

 

[BobD777]

That's the first thing to check, sorry. I always carry spare T&P's on the van.
They release at 150 PSI
If they are dripping and the pressure to the home is like 120 and lower, it's gone bad. Typically if you don't touch them, they last as long as the water heater. In theory, you test them every so often. Doing so, it's a good idea to have a replacement on hand, because once you start check them, they can quit sealing.

I'm actually grateful for having to work through this problem, as it forced me to learn how all these components work together! I always had a cursory understanding of the system, but never really got the whole picture. But as much as I like to learn, I'm hopeful that this episode is done with! My boiler pressure is at 25psi, right now, so I'm keeping an eye on it.

Actually, I'm learning all this just as I'm about to install a hybrid hot water heater. After that, my entire boiler system will no longer be used--unless in the unlikely event that it's needed in its role as backup heater for our geothermal system. Better late than never

 

[BobD777]

Is the pressure in the boiler still at 20 lbs and relief leaking or did the pressure creep up. If it did lower pressure back down to 20 lbs and valve water regulator off . Keep a eye on the boiler pressure for 24 hours and if water pressure raises coil in water heater is compromise.

Fitter, looks like you called it. The pressure has been creeping up and the new pressure relief valve did open. I'm going to guess what you meant by "coil in water heater is compromised".

I'm thinking you were saying that if the coil is compromised, the higher pressure water from the water tank, is getting into a hole in the coil, and so slowly raising the boiler pressure. Sounds like a terminal condition.

Am I close?

Fortunately, if that is the case, I was already in the process of ordering a new hot water heater.

Thanks again--

 

[Reach4]

Fitter, looks like you called it. The pressure has been creeping up and the new pressure relief valve did open. I'm going to guess what you meant by "coil in water heater is compromised".

Have you closed off the incoming supply valve from the potable water to auto-fill? If not, the problem could be a leaky auto-fill valve. That is an alternative cause of pressure rise. Maybe that was previously addressed.

 

[BobD777]

Have you closed off the incoming supply valve from the potable water to auto-fill? If not, the problem could be a leaky auto-fill valve. That is an alternative cause of pressure rise. Maybe that was previously addressed.

So simple! Of course. That was discussed, but I never closed the valve to test it, since the pressure release valve was leaking up until yesterday when I changed it. I've now closed the valve and will keep an eye on it to see what it does going forward. Thanks!

 

[Sylvan]

On my van I used carry a TP valve a safety valve set 15 (stream) and a relief valves M and F threads set for for PSI as it is a good idea when testing these valves to always have a spare on hand plus the auto feeder and 9 D etc along with a B&G series 100 and extra couplers

 

[BobD777]

On my van I used carry a TP valve a safety valve set 15 (stream) and a relief valves M and F threads set for for PSI as it is a good idea when testing these valves to always have a spare on hand plus the auto feeder and 9 D etc along with a B&G series 100 and extra couplers

As a professional, it pays to be prepared. I'm on my third TP valve with this episode.

 

[BobD777]

Is the pressure in the boiler still at 20 lbs and relief leaking or did the pressure creep up. If it did lower pressure back down to 20 lbs and valve water regulator off . Keep a eye on the boiler pressure for 24 hours and if water pressure raises coil in water heater is compromise.

Well, on the suggestion of another poster, I turned the valve off that supplies water to the pressure reducing valve. Even with that, the pressure keeps slowly creeping up every day. So I'm now going with your wisdom on the water heater coil being compromised. The good news is that changing my HWH will feed two birds with one seed-- the coil leak and the incorrectly piped desuperheater.

Thanks again for your help-

 

[Sylvan]

Normally when a relief valve leaks I look at the tri indicator on the gauge

If the pressure is high I open the relief valve and wait to see it it sets itself

4 things cause a relief valve to leak

1- Bad relief valve (rare)

2- auto feeder set to high

3- expansion tank full or bladder lost some charge or undersized

4- Tankless coil as you found out

 

[BobD777]

Normally when a relief valve leaks I look at the tri indicator on the gauge

If the pressure is high I open the relief valve and wait to see it it sets itself

4 things cause a relief valve to leak

1- Bad relief valve (rare)

2- auto feeder set to high

3- expansion tank full or bladder lost some charge or undersized

4- Tankless coil as you found out

You're describing the course of my last week.