Why would my pressure relief drip leg leak a little?

melo

I’ve gotten notification throughout the night that the boiler room leak sensor was going off at my parents. I get there and it looks like the relief valve leg was leaking a little bit. I checked the pressure gauge and it seemed fine.

I know it’s not standard but our boiler is set up to a little higher pressure than I’d like. But anyways I saw that the pressure gauge showed it got to close to 5 psi then turned off automatically.

So I don’t think it got close to 15 psi when the relief valve would technically open up.

Any ideas? Should I replace the relief valve?

Long Beach Ed

First, make sure the leak is from the valve and not from the boiler.

If it is the valve, check that the pressuretrol pigtail is not clogged. Then test the pressuretrol and make sure it will cycle the boiler properly. Then consider that the pressuretrol valve may not be not seating correctly and is leaking. If it's leaking it should be replaced.

melo

I watched the pressuretrol and it's not leaking from the pressuretrol.

I watched as the pressure gauge climbed up to about 5 PSI then the boiler shut off before starting back on when the pressure decreased. I had replaced the pigtail about 2 months ago and made sure there wasn't any clog inside.

Is there any easy way to check the pressuretrol other then just watching the boiler?

As for the valve, which has the drip leg leaking a little. Is it possible that the valve went bad? I plan to replace the valve to see what happens.

PDTech

I had a T&P valve leaking intermittently. I gave it a sharp rap with a hammer, and it has not leaked for several years now. (I assume it was not fully seated)

Long Beach Ed

The valve is likely installed improperly and should be installed in a "vertical upright position". Otherwise mung (technical term) can settle on the seat or clog the flow causing its failure. You can check the valve maker's literature.

A PDTech said, you can try reseating the valve by playing with the handle and flushing debris from the seat.

Most manufacturers require the valve to be tested every two months by opening the lever and flushing for five seconds to clear accumulated debris from the seat and assure it's not blocked.

It's not uncommon for improperly installed valves to leak and require replacement. Use a properly sized valve. Never plug the discharge line.

AdmiralYoda

1. Why are you operating at such a high pressure? I see no reason or benefit of running so high.
2. The pressure relief valve is not installed correctly. It is installed horizontally and should be installed vertically. I'll bet some rust/debris has made it its way into the valve and it isn't sealing properly.

melo

https://forum.heatinghelp.com/discussion/comment/1846384#Comment_1846384

Because my boiler is oversized and short cycles, only way to keep it from turning on and off every minute. This makes it do it every 5 minutes or so until the temp is fulfilled. :(

What fitting would I need to be able to have the relief valve vertical then an offset to run the "drip" pipe?

Jamie Hall

The boiler being oversized is no excuse for operating a boiler at excess pressure. All that does is make the added fuel use and expense worse — as well as damaging all the vents and traps.

Crank it down where it belongs.

AdmiralYoda

Echoing what @Jamie Hall said. The cost of fuel forcing the boiler to operate at higher pressures far outweighs the annoyance of the boiler short cycling. Add to that the cost of damaged vents, traps, etc.

My boiler is oversized and short cycles as well but I still use a vaporstat that cuts it out at 16oz (1psi). Hearing the boiler cut out and short cycle annoys me but it is better than sending money up the chimney.

And to fix your safety release valve all you will need is a short nipple and a 90 degree elbow. It should look like the picture below. This is my boiler and I went through the same exact thing as you.

Hap_Hazzard

Why do you think they call it a "drip" leg? 😂

But, seriously, you're supposed to replace those things every now and then, leaks or no, and it's supposed to be mounted upright. (I always save the most recent ones if they're not leaking, just in case the new one fails.) You're also supposed to test them now and then. If they don't close completely, they need to be changed.

EdTheHeaterMan

I could not read the details on that relief valve, but it reminds me of a Temperature Pressure relief valve for a water heater. Steam is hot enough to cause a temperature element to open slightly during a run cycle. Check that the pressure setting for that valve is 15 PSI.

As far as short cycling is concerned, you can add a Time Delay to the gas valve circuit that will prevent the burner from operating until the 5 or 10 minute adjustable delay is satisfied. The boiler will then be able to operate at a much lower pressure and use less fuel. Higher pressure = more energy used.

Here is one other post about this idea

https://forum.heatinghelp.com/discussion/comment/1829103#Comment_1829103

and this one

https://forum.heatinghelp.com/discussion/comment/1842061#Comment_1842061

Bur not everyone agrees, so you choose. higher gas bill with higher pressure, short cycling with lower pressure, or lower pressure with time delay.

I hope this helps.

techforlife

Is this an oil fired boiler or gas? If oil fired, just lower the firing rate.