Leaking valve

Reply

  #1  
Old 12-23-20, 12:50 PM
2
Member
Thread Starter
Join Date: Jan 2014
Location: USA near Boston, MA
Posts: 1,115
Received 82 Votes on 69 Posts
Leaking valve

A valve (made in China) for underfloor heating that was installed 8 years ago just started leaking enough to create a small puddle below the boiler. Have routed it to a bucket and collect about 1 gallon per day.


Water dripping from valve.

Apparent source of the leak at the top of the valve.

The input side is threaded onto steel pipe that tees off of a supply manifold. There is no shutoff valve between the boiler and the manifold so I will have to shut off all zones to isolate the manifold and slightly drain the boiler to remove it. The output side is threaded onto steel that goes to copper that I can cut for removal.

Since we are well into the heating season, I would like to postpone this repair until next spring. I can continue to empty the bucket and will deal with any air introduced into the system by the makeup water as needed. The makeup water valve is usually closed but I have opened it for now.

Looking at the source of the leak, i think I can loosen the bonnet and install additional or new gasket material. If that solves the problem then I will not have to replace the valve (with a ball valve.)

Would it be possible to not remove the bonnet completely but loosen it enough to insert some graphite string or sealant into the joint?

Any ideas about a temporary fix to stop the leak until a more appropriate time to fix or replace?

I already tried to tighten up the bonnet but it is as tight as it will go.

I'm not sure if it is related to the leak but when I discovered it the boiler pressure was low (makeup valve closed), there was some very slight water residue in buckets under both the boiler safety valve and the input water safety valve. I relieved pressure in the air tank (bladder style) and drained it. The tank air pressure was lower than I usually keep it so I repressurized it.
 
  #2  
Old 12-23-20, 01:38 PM
B
Member
Join Date: Oct 2015
Location: Ct.,USA
Posts: 1,982
Received 107 Votes on 94 Posts
Did you have the stem fully open when you attempted to tighten the bonnet? Did you use a box wrench on the bonnet hex?
 
  #3  
Old 12-23-20, 01:46 PM
2
Member
Thread Starter
Join Date: Jan 2014
Location: USA near Boston, MA
Posts: 1,115
Received 82 Votes on 69 Posts
Did you have the stem fully open when you attempted to tighten the bonnet?
Yes.

Did you use a box wrench on the bonnet hex?
Adjustable wrench snugged up tight.

The bonnet was as tight as it could be. No movement at all.

I did not try to back it off and tighten again. I hesitate to do that now in heating season in case I make it worse or the valve body disintegrates.
 
  #4  
Old 12-23-20, 06:27 PM
D
Member
Join Date: Apr 2014
Location: us
Posts: 1,065
Received 47 Votes on 45 Posts
A temporary quick fix might be to wrap it with band of rubber or soft gasket material and tighten worm gear hose clamp around it. And maybe first coat area with some kind of sealer.
 
2john02458 voted this post useful.
  #5  
Old 12-23-20, 07:21 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,489
Received 1,422 Votes on 1,315 Posts
Interesting place to leak. Looks like a nylon washer which usually don't go bad which leaves a casting issue. Have seen a lot of casting issues with Asian plumbing fittings.

I like your thinking on the graphite bonnet packing. That's something I certainly would try.
Might need a wrap or so on either side of the nylon washer. Tighten gently so as to not force it out.
Make sure the system is cool before trying it and shut off the water fill.

Graphite bonnet packing
 
2john02458 voted this post useful.
  #6  
Old 12-23-20, 08:53 PM
D
Member
Join Date: Apr 2014
Location: us
Posts: 1,065
Received 47 Votes on 45 Posts
DH for 60 years has been going to China and knows how things work there.

2John valve is "Bu-hao” in Mandarin Chinese means “no good”.

Valve body is probably low grade and porous. Gasket is whatever. Joint is likely now corroded.

2John should just try quick fix and have a Merry Christmas. “gung chi fa choi”
 
2john02458 voted this post useful.
  #7  
Old 12-26-20, 11:35 AM
2
Member
Thread Starter
Join Date: Jan 2014
Location: USA near Boston, MA
Posts: 1,115
Received 82 Votes on 69 Posts
Temporary fix

A small strip of roofing membrane that has a sticky rubber-like sealant that expands when it gets hot, a strip of soft rubber gasket, and a hose clamp.





Still dry after 24 hours.

Thanks to DH for the suggestion.
 
 

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