Noticed the pressure relief valve on my burner was leaking today. It doesn't start to leak until after the burner comes up to temp and shuts off. It looks like a pressure issue to me as the gauge reads 30psi at temp which I think is what the PRV is set to open at. The expansion tank was replaced about 5 years ago and is an extrol mode 30. The pressure when the burner is not running is down around 12 which from what I could gather from the Internet is normal. Do the expansion tanks go bad in 5 years or should I be looking for another issue?
SteveM
Had similar on my water heater a few years ago.
Made service call to my oil company.
They came and replaced the Calverton unit. Fine ever since.
Made service call to my oil company.
They came and replaced the Calverton unit. Fine ever since.
Bad expansion tank. The T&P starts to open before the rating fyi. Those valves should be exercised annually.
Try airing up the tank and see what happens. Air is absorbed by water, so if you get the same symptoms reappering in a few weeks, swap the tank.
At least, that's what I'd do.
At least, that's what I'd do.
There is an airbag in the expansion tank. If there is no air in the airbag, then it's no longer functioning as an expansion tank. It just becomes a tank.
And yes, I've had one fail at about the 6 year mark.
And yes, I've had one fail at about the 6 year mark.
First, to see if you expansion tank is full of air or water, you can thump it on the side.
The Extrol tank has a schrader tire inflation valve on it (under a screw on plastic cap). See if there is air pressure (like how you'd check your car tires). If water comes out of this, the bladder in the tank is definitely shot and you need a new expansion tank. There should be around 12-13PSI of air in the tank when the system is cold (on a typical system; YMMV). If there is no pressure in there in a cold system, but no water either, you can pump it back up with a bicycle pump, and perhaps the schrader valve is leaking air.
The Extrol tank has a schrader tire inflation valve on it (under a screw on plastic cap). See if there is air pressure (like how you'd check your car tires). If water comes out of this, the bladder in the tank is definitely shot and you need a new expansion tank. There should be around 12-13PSI of air in the tank when the system is cold (on a typical system; YMMV). If there is no pressure in there in a cold system, but no water either, you can pump it back up with a bicycle pump, and perhaps the schrader valve is leaking air.
If your gauge reads 30 psi when the burner shuts off, check your temp and check your water inlet pressure. If the shutoff temp was somehow raised the pressure will go up. If the inlet water pressure was raised the pressure will go up. Both conditions can cause the pressure to reach/exceed 30 psi and that will cause the valve to do its job and open slightly
Thanks for the suggestions, went to check the pressure on the expansion tank and all I got out of it was water so it looks like that is the culprit. I see there only about $40 at home depot so I will pick one up and replace it. Just have questions on replacing it now. From looking at this site http://www.completeplumbingsource.com/replace-a-heating-expansion-tank , it seems pretty easy but do I need to adjust the air pressure inside the new expansion tank or just leave it how it comes out of the box?
OK, gotcha. My apologies. Do not fill the tank.
I'm going to choke the guy who works on my gas burner.
I'm going to choke the guy who works on my gas burner.
I believe you match the expansion tank pressure for your hot water heater with the house pressure or just slightly lower.
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