How tight to screw in the T&P Relief Valve?

Reply

  #1  
Old 07-15-13, 03:40 PM
Member
Thread Starter
Join Date: Oct 2002
Location: USA
Posts: 26
How tight to screw in the T&P Relief Valve?

I recently tested my T&P relief valve and after I released the lever it kept dripping for several hours, so I decided to replace it. I got a Cash Acme from Home Depot. When I screwed it in when it got tight the outlet was not pointing straight down. I tried tightening further but was scared it would be too tight and possibly damage the threads in the water heater. So instead I backed it off a bit so that the outlet is pointing down. It doesn't leak at the screw-in point but it is slightly loose and will rotate back and forth.

My question is -- should I leave it as is since it doesn't leak, is there any downside to that? Or should I put a wrench and some muscle on it to give it 1 more turn? How do I tell if I am over-tightening it and could it crack something?
 
Sponsored Links
  #2  
Old 07-15-13, 06:59 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,400
You can put quite a bit of pressure on the wrench when turning in pipe fittings. Unless you are a professional wrestler I doubt that you will overtighten the valve.
 
  #3  
Old 07-15-13, 07:02 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 17,677
The main issue is why was the relief valve leaking???? Often faulty expansion tank or PRV valve... Very rarely the relief valve from my experience....
 
  #4  
Old 07-15-13, 07:52 PM
Banned. Rule And/Or Policy Violation
Join Date: Apr 2013
Location: USA
Posts: 4,297
You did use pipe dope on the threads, right?
 
  #5  
Old 07-15-13, 08:33 PM
Member
Thread Starter
Join Date: Oct 2002
Location: USA
Posts: 26
Thanks everyone for the quick replies.

@joecaption1: The new valve came with some white stuff already on it -- either pipe dope or teflon tape. In any case I added about 3 turns of teflon tape before screwing it in.

@lawrosa: I don't have an expansion tank. The old PRV was not leaking until I tested it, then it kept dripping, so it probably wasn't seating right. I've checked the pressure, it's 50 psi and the temperature is normal.

The new PRV is NOT leaking, I just want to know if I should tighten it further. Seems like it'll be OK to do so, but the question still is -- do I need to do it, any harm in just leaving it as is -- slightly loose?
 
  #6  
Old 07-15-13, 08:45 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 17,677
Loose??? Put an 18" on it and turn it once more...

PRV I am talking about one for the main... But is psi is 50 you OK i guess...

 
  #7  
Old 07-15-13, 09:02 PM
Banned. Rule And/Or Policy Violation
Join Date: Apr 2013
Location: USA
Posts: 4,297
Just tighten it up.
Very common problem to have a pressure relief valve leak when you check it by flipping up the tab.
No it's not ok to leave it loose.
 
  #8  
Old 07-16-13, 01:48 PM
Member
Thread Starter
Join Date: Oct 2002
Location: USA
Posts: 26
Thanks everyone. I will tighten it up, but just wondering, what would be the problem if left loose?
 
  #9  
Old 07-16-13, 04:30 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,400
Problem? It will eventually leak. Did you re-connect the drain piping?
 
  #10  
Old 07-17-13, 07:18 AM
Member
Thread Starter
Join Date: Oct 2002
Location: USA
Posts: 26
Yes, I did. Thanks again for the advice.
 
  #11  
Old 07-18-13, 02:11 PM
Member
Thread Starter
Join Date: Oct 2002
Location: USA
Posts: 26
OK, I was able turn it 1 more turn without too much trouble and it feels fairly tight. However, I'm still wondering, how do I know if it's tight enough? Do I keep turning until it just won't go any more and then back it off until the outlet points down? Or if it feels fairly tight and nothing is leaking then I'm done?
 
  #12  
Old 07-18-13, 10:49 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,400
How long was the handle on the wrench? Most likely your ARE done but please let us know about the wrench you used.
 
  #13  
Old 07-19-13, 06:09 AM
Member
Thread Starter
Join Date: Oct 2002
Location: USA
Posts: 26
I used my biggest wrench which is 14 inches. If need more force I usually put a pipe on the handle to get extra leverage, but didn't do that this time.
 
  #14  
Old 07-19-13, 11:37 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,400
A 14 inch wrench is fine.
 
  #15  
Old 07-19-13, 01:15 PM
Member
Thread Starter
Join Date: Oct 2002
Location: USA
Posts: 26
Thanks for the quick reply. I take it you mean I'm done, no need to tighten further?
 
  #16  
Old 07-19-13, 01:22 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,400
You're finished with that job, time to move to the next one.
 
  #17  
Old 07-19-13, 01:36 PM
Member
Thread Starter
Join Date: Oct 2002
Location: USA
Posts: 26
Great, thanks for all your help!
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes