Relief Valve Leak

Jimbo_5

Started cleaning my basement a bit. A few hours later I noticed about a cup full of water spillage on the floor. Never had this before, so I started looking around. Then I notice the pressure on the boiler approaching 30 psi. Never anywhere this high before.
I opened a drain valve a little to release the pressure to 20#. When the boiler shut off the pressure began to climb again. I released a bit more. Started rising again. I checked the makeup water, 12 psi. As I sat there waiting for the boiler to fire again I noticed the gauge slowly rising again, and several times I'd let out a little pressure bringing it back to 12# and it slowly crept up to 14#.
When the boiler fired it was alright till the temp got up to 140 degs the psi started climbing past 25#, so I let out some pressure. This continued several times.
The boiler is a Triangle Tube Prestige 110, installed in 2008, along with a new expansion tank. The tank sounds hollow on the lower 1/3 but it is cold all over. I hit the schrader pin and air came out. Got me twisted!
Any help will be greatly appreciated.

STEVEusaPA

Time to call a pro.

nicholas bonham-carter

Valve off the makeup water, and observe the pressure for awhile.
Is your boiler also making hot water? Try turning off the water feed to the tank as well. One of these sources is the likely culprit.—NBC

Jimbo_5

Thank you. I valved off the makeup water at 12 psi. Slowly it crept back up to 14 psi, so I opened a drain valve for a split second letting out about a cup of water going back to 12. Again it slowly crept up, and again I vented it. When she fired again, it rose to around 20 psi for a bit but as the temp went up so did the pressure all the way to 30 psi.
The indirect HW tank seems to be functioning fine pushing 194 deg water thru the tank. The boiler gauge remained at 12. Though I don't know if the boiler gauge is connected to that internal loop. The gauge on the heating loop, right where the spirovent connects the makeup water and expansion tank only fluttered a bit but didn't rise more than a half-pound then returned to 12 psi (it's only a 0-30 gauge).
I will valve off the indirect tank to see if that helps. Over night I left a bucket under the pressure relief valve at the makeup water, where it has been leaking from. Makeup water was off. I found less than a quart of water in the bucket and the gauge reading 14 psi. It is maddening...... Thanks again!

nicholas bonham-carter

There could be a pinhole leak in the tubing inside the indirect, which allows the water to leak from the cold side into the boiler water, because the street water is at higher pressure.—NBC

EBEBRATT-Ed

@Jimbo_5

It's one of 3 things.

Bad expansion tank

MU water leaking ito boiler ..bad PRV

Or leaking coil in the indirect

Valve off the make up water for 1/a day and see what happens

If that doent work open the make up and valve off the indirect

If it's neither one of those it's the expansion tank

Jimbo_5

Thanks guys. After testing several possibilities, it turned out to be a bad expansion tank. It sounded hollow, it let out air when depressing the schrader pin. Live and learn. Thanks again.

EdTheHeaterMan

The expansion tank is supposed to let out air when you depress the Schrader valve. But you are not supposed to let the air out by depressing the Shrader valve. The proper way to test an expansion tank is to use a tire pressure gauge on the Schrader valve when the boiler pressure is reduced below the expansion tank pressure. By letting out the air, you have reduced the capacity of the expansion tank (if it is still good)

The most likely cause of the pressure increase is a pinhole in the DHW tank on the coil that separates the potable (higher pressure) water from the boiler water (lower pressure

Second most likely reason is the fill valve is defective, or set too high and the isolation (manual operated) valve is no closing fully.

Jimbo_5

Thanks, Ed. I called Amtrol and they advised tapping the side of the tank and quickly depressing the schrader to see if water came out. When I removed the tank from it's awkward position and tested its pressure--it had none, nor would it hold any when pumped. Just to be sure, tomorrow I will replace the PRV setup and the ancient globe valve with a ball valve. Thanks for offering your help.

EBEBRATT-Ed

Expansion tank failure is by far the most common reason for relief valves to open. Not saying there arn't other reasons