Replacing a pressure relief valve

Old 09-25-18, 09:27 PM
Thread Starter
Join Date: Aug 2016
Location: USA
Posts: 30
Upvotes: 0
Received 0 Upvotes on 0 Posts
Replacing a pressure relief valve

Older furnace needs to have its pressure relief valve replaced.

The existing valve is rated for 550,000 BTU/Hr but all the ones I have found online seem to cap at 510,000. I assume since the furnace output 90,000 BTU/Hr that the ones rated 510k are fine?

Is there a preferred brand I should look for based on quality?

Lastly, the expansion tank looks original so its gotta be 40 or so years old. Is it wise to replace that as well while we're at it.

Attached Images  
Old 09-25-18, 09:45 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 66,020
Received 4,156 Upvotes on 3,732 Posts
Thread moved to the boiler forum. A furnace is hot air.
Old 09-26-18, 06:16 AM
Join Date: Oct 2008
Location: USA
Posts: 2,606
Received 28 Upvotes on 27 Posts
Anything over the boiler input rating will be OK. It's 112,500 Btu/hr, not 90,000. The most common brand is Watts, but I wouldn't worry too much.

Is it a bladder-type expansion tank or a conventional, horizontal tank? A bladder-type tank looks like a propane cylinder for a BBQ grill. A conventional tank will last indefinitely, a bladder tank will eventually fail and will require checking and replenishing the air periodically. There is a sticky on this forum that tells how.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: