trickling pressure relief due to 120lbs in-home?


  #1  
Old 01-26-08, 10:54 PM
G
Member
Thread Starter
Join Date: Jan 2008
Location: herriman utah
Posts: 7
Upvotes: 0
Received 0 Upvotes on 0 Posts
trickling pressure relief due to 120lbs in-home?

i'm in serious need of advice:
all of this started with the water heater-it split down the back and started leaking like crazy and had to be replaced. that was done a week or so ago and shortly afterward the thermal relief began to trickle. (forgive me-this is the ball valve that has a tube sticking out of it-i'm an electrician and am not sure what all of the terminology is exactly-expansion valve? thermal relief valve? 125psi thermal expansion relief valve?)

so i replaced the expansion valve. that was not the problem-it kept trickling. so i hooked a guage to a bib and found that the pressure went through the roof after a faucet was closed. somewhere around 120lb. i guessed that the regulator(i've heard it referred to as a prv?) was bad-so i replaced it. i tested for leaks and things were good so i turned it back on. it worked like a champ-i set it at 60 and called it good. it looked good for a while...til i realized the expansion valve was trickling yet again. the bib guage was at 140! i know i set the prv correctly-i adjusted it, turned on a faucet, adjusted it again and it held at 60.

i'm ready to snap.

any input would be great. i'm running out of things i can replace
 
  #2  
Old 01-27-08, 04:48 AM
J
Member
Join Date: Oct 2006
Location: Wilmington
Posts: 3,994
Upvotes: 0
Received 0 Upvotes on 0 Posts
Most T&P(temp/pressure relief valve), are rated at 210deg/150lbs, but they often trickle before reaching that point. If you have stabilized the pressure at 60lb, it should work, and an expansion tank is normally not necessary. But the pressure spiking when a valve is shut off could be a faulty antihammer system. The simplest anti hammer is a piece of verticle pipe where the water line enters the house, usually 2-3' long with a cap on it. That is supposed to be full of air and acts as a cushion. They often become waterlogged(air dissolves into the water), and must be drained or opened to get that air cushion back. There are types of antihammer gadgets that work better longer, but this is what most homes will have.
 
  #3  
Old 01-27-08, 07:40 AM
G
Member
Thread Starter
Join Date: Jan 2008
Location: herriman utah
Posts: 7
Upvotes: 0
Received 0 Upvotes on 0 Posts
this is the first time i've heard mention of an "anti-hammer" is this just like a dead end of pipe(it wouldn't be in line, right?) where it enters my house? and what if i don't have one?


is the t&p on the water heater itself? the one that is trickling is about a foot before the water heater on the incoming line , on the shutoff for the water heater.
 
  #4  
Old 01-27-08, 12:30 PM
5
Member
Join Date: Nov 2004
Location: CA
Posts: 1,913
Upvotes: 0
Received 0 Upvotes on 0 Posts
This has nothing to do with hammer. The T/P valve is on the water heater itself, either on the top, or near the top on the side. It has a toggle test lever on it. And usually a pipe connected to it leads either straight down near the floor, or out through a wall.

Assuming your new Pressure Regulator is OK, newer water heaters are susceptible to pressure build up as the burner is running. The pressure regulator valve may bypass this to the street, but only when house pressure exceeds street pressure. Most WH manufacturers today recommend an expansion tank for this reason. Some municipalities require it.

Massachusetts and some other states require vacuum breaker on the cold inlet pipe. That may be the device you describe as leaking. It just needs to be replaced. If you could post a picture, or read the label on it, that would help us.
 
  #5  
Old 01-27-08, 12:37 PM
L
Member
Join Date: Mar 2000
Location: Arlington, WA
Posts: 8,670
Upvotes: 0
Received 1 Upvote on 1 Post
gonzo499,

Forget about the antihammer devices for now. You need to figure out and fix the pressure problem. Thee's no way it should be creeping back up once the PRV is properly set.

The PRV should be the very first thing in the line past the water meter, with the possible exception of a tee for landscape watering. The hose bibb is on the cold water line, so you should be able to shut the water to the WH off (although you shouldn't have to), put the guage on the bibb and read the pressure by opening the bibb with all other faucets and bibbs in the house shut off. If that pressure is over 60 lbs., adjust the PRV down. Open a bibb or faucet for about 30 seconds and let the water run. Shut that off and recheck the pressure on the guage. You might have to do that a few times to get it down to the range of 45 to 60 lbs., but once you have it there, it should stay.

If it doesn't, and since the PRV is new, I would suspect that something in the house is plumbed wrong and is bypassing the PRV.

How old is the house? Are you the original owner?
 
  #6  
Old 01-27-08, 02:24 PM
G
Member
Thread Starter
Join Date: Jan 2008
Location: herriman utah
Posts: 7
Upvotes: 0
Received 0 Upvotes on 0 Posts
since there is no football on today and i've got nothing to do but monitor my water pressure i've noticed that it seems to only build after i've used a bit of hot water-which leads me to believe that 594tough was on the right track with the pressure building with the temp rising(i.e. thermal expansion?)

-the trickling valve i replaced first reads "water heater shutoff-thermal expansion" it seems ridiculous to me though that the only expansion relief i have is this valve that is set at 125lb-this seems too high for it to stay for any period of time. it has to be hard on the pex and stuff doesn't it?

-the plumber that replaced my water heater said that the expansion valve is what he installs now instead of expansion tanks-which brings me back to the 125lb issue


is an expansion tank going to be my answer? is there anything else i can do?

thanks to all of you-i really appreciate your input.
 
  #7  
Old 01-27-08, 06:31 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 16,321
Received 39 Upvotes on 31 Posts
In my opinion the relief valve to release excess pressure due to thermal expansion is a stupid fix as it wastes water and is far more subject to failure than is an expansion tank.

Install the proper expansion tank and remove the silly thermal expansion relief valve is what I would do.
 
  #8  
Old 01-27-08, 08:35 PM
L
Member
Join Date: Mar 2000
Location: Arlington, WA
Posts: 8,670
Upvotes: 0
Received 1 Upvote on 1 Post
gonzo499,

This is obviously an expansion problem, and my limited expertise in plumbing doesn't include that. I'm going to leave this one to the pros like furd and the rest of the plumbing contractors in here. I'll just keep tabs on the thread so I can learn something!!

Furd -- PM me -- just where in the northwet are you?? I called it home for almost 20 years, and still have lots of family north of Seattle. Get up there at least once a year.
 
  #9  
Old 01-29-08, 11:18 AM
Beachboy's Avatar
Member
Join Date: Nov 2006
Location: Northeast Kansas
Posts: 704
Upvotes: 0
Received 1 Upvote on 1 Post
I'm with furd -- the water heater pop off valve is not designed for continual duty as an expansion relief device. Besides, as you've noted, it pops at 125#, which is too high for residential use. Typically, 60# is the optimum residential water pressure. I'd definitely look into an expansion tank, as thermal expansion from your water heater cycling is causing the problem. The PRV is acting as a check valve, preventing the excess pressure from relieving into the city's water distribution system. Most municipal water customers are fed directly from main pressure, which is typically in the range of 40-60#, and any thermal expansion bleeds back into the distribution system. However, systems such as yours with the distribution system operating at a high pressure and requiring the use of a PRV at each customer's service, requires that an alternative method be used to compensate for thermal expansion from the water heater. At one time, Watts sold a toilet tank ballcock which included a small expansion valve that allowed excess pressure to bleed off into the toilet tank.
 
  #10  
Old 01-29-08, 06:35 PM
G
Member
Thread Starter
Join Date: Jan 2008
Location: herriman utah
Posts: 7
Upvotes: 0
Received 0 Upvotes on 0 Posts
new problem!
thanks again for all of the help, i picked up an expansion tank yesterday i'm going to put in soon.
i'm experiencing something new today though-my brand new water heater was no longer lit when i got home from work just now. i'm hoping the wind blew out the pilot through the flue-is that possible?
 
  #11  
Old 01-29-08, 09:29 PM
G
Member
Thread Starter
Join Date: Jan 2008
Location: herriman utah
Posts: 7
Upvotes: 0
Received 0 Upvotes on 0 Posts
when i relight: the pilot kicks on fine but the main burner begins pointing down and goes out after about 2 seconds

i have tried to light it repeatedly with the same results

i really need to shower and am ready to freak out.
...again
 
  #12  
Old 01-30-08, 01:15 PM
L
Member
Join Date: Mar 2000
Location: Arlington, WA
Posts: 8,670
Upvotes: 0
Received 1 Upvote on 1 Post
Replace the thermocoupler.
 
 

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