temperature relief valve is dripping water

Reply

  #1  
Old 04-12-10, 12:00 PM
Member
Thread Starter
Join Date: Nov 2007
Location: IL, USA
Posts: 42
Received 0 Votes on 0 Posts
temperature relief valve is dripping water

Hello,

I have a 2006 State Select gas water heater. 2 weeks ago, I noticed water stained on the floor where the TRP valve/drain pipe is. As it turns out the TRP valve/draining pipe would occasionally drip a little bit of water after it heats up the water. Is this normal? Do I need to replace the trp valve or some other parts of the water heater?

Someone suggested that I test the TRP valve by pulling the lever up (thus releasing some water) and closing it back. Would this fix the dripping?

I'd appreciate any of your ideas/suggestions. Thanks.
 
Sponsored Links
  #2  
Old 04-12-10, 12:32 PM
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
You can try lifting the manual operator for a few seconds. Maybe that might flush crud out of the valve. If that doesn't help, replace the valve with one of the same rating.

No, it is not "normal" for the T&P valve to leak.

Are you hooked up to a municipal water supply? If so and there is no check valve or backflow preventer, you shouldn't need an expansion tank. If you have a well, and the air tank becomes waterlogged, it's possible that your water system could become over-pressurized due to thermal expansion. It such a situation occurred, you should notice short-cycling of the well pump.
 
  #3  
Old 04-12-10, 12:32 PM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,107
Received 0 Votes on 0 Posts
It may fix the drip if there is some sort of grit or contamination on the seat of the valve. If its never lifted or you never test it..then grit or debris is unlikely.

Its possible the valve has "weakened" enough that the normal heating (and subsequent expansion) of water in the tank is causing the drip of water. Replacement of the valve might stop it...but a better solution would be an expansion tank on the hot water line. Of course that's assuming you don't have one now. If you do..check to make sure its not water logged.
 
  #4  
Old 04-12-10, 07:40 PM
Member
Thread Starter
Join Date: Nov 2007
Location: IL, USA
Posts: 42
Received 0 Votes on 0 Posts
Thanks for replying. No, I've never tested the valve before. Yes, I'm hooked up to a municipal water supply and I don't see an expansion tank connected to my water heater. I guess I'll have to definitely replace the valve. Thanks again.
 
  #5  
Old 04-13-10, 07:31 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 1 Vote on 1 Post
Before replacing the valve, why not throw a pressure gauge on there and see if there is a REASON the valve is lifting? Would you want to go to the trouble of replacing the valve and finding the new one does the same thing? Happens all the time...

Lowes, HD, have gauges that screw onto a hose outlet and will record the pressure. About $10 or so, well worth the cheap diagnostic price. Look for them in the lawn sprinkler section, it's a gauge with a hose fitting on it. Screw it on to the fitting and leave it for a day or two. If you find the pressure has peaked out at 125 or 150 PSI, then you know the valve is lifting from the pressure.

Also, being a T AND P valve, it's always possible that the thermostat on the heater has gone outta whack and the water is getting way too hot... have you noticed any difference in the temperature?
 
  #6  
Old 04-13-10, 11:45 AM
Member
Thread Starter
Join Date: Nov 2007
Location: IL, USA
Posts: 42
Received 0 Votes on 0 Posts
Thanks NJ Trooper. I'll buy a pressure gauge and test it. Pardon my ignorance but just to make sure I understand things correctly, if the pressure peaked out at 125 or 150 psi then I should definitely replace the relief valve, is that right? About the temperature, I noticed 2 weeks ago that it was set at 145 degrees so I lowered it then to just 120 degrees. Even when I lowered the temperature setting (& the hot water that comes out is not as hot as it used to be), the draining pipe would still occasionally leak.

Thanks again. I appreciate the help.
 
  #7  
Old 04-13-10, 01:21 PM
rbeck's Avatar
Member
Join Date: Jul 2007
Location: Pennsylvania
Posts: 2,449
Received 1 Vote on 1 Post
just for your info if you add an expansion tank it goes on the cold inlet not the hot outlet pipe. A new relief valve may help but the tank should be added also.
 
  #8  
Old 04-13-10, 02:06 PM
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
Originally Posted by canon2 View Post
Pardon my ignorance but just to make sure I understand things correctly, if the pressure peaked out at 125 or 150 psi then I should definitely replace the relief valve, is that right?
No, a typcial T&P valve is set to relieve at 150 psi (or 210 deg F). If your pressure is anywhere near 150 psi, the dripping valve may be performing as intended.

But, you would then need to figure out why the pressure is so high. The pressure of municipal water systems is typically around 60 psi. Unless there is a check valve in the city water supply, it seems unlikely that your water pressure, hot or cold, would be higher than the city's pressure.

An expansion tank may be required in your jurisdiction, but many locations do not. A expansion tank could prevent overpressurizing the system if somebody mistakenly valves out the water supply to the water heater without turning off the gas.
 
  #9  
Old 04-13-10, 05:20 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 1 Vote on 1 Post
I seem to recall that we learnt recently that most of the newer water meters have check valves built in... and if there is a check valve anywhere between the heater and the city water supply, you need the expansion tank. It's the heating of the water that will cause it to expand enough to raise the pressure in the system above the city supply.
 
  #10  
Old 04-14-10, 11:04 AM
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
Originally Posted by NJ Trooper View Post
I seem to recall that we learnt recently that most of the newer water meters have check valves built in...
You got me worried, so I called Badger Meters - who supply most of the water meters around my area. None of their water meters have built-in check valves.

If anybody has a water meter from another manufacturer, you could call them or the water utility to verify whether or not the meter has a built-in check valve.

Without a check valve, I don't think an expansion tank is necessary, although it might be nice in the event that the water heater is valved out without turning off the fuel supply.

Well water supplies would be a horse of a different color. I think they usually have a foot valve at the bottom of the well casing.
 
  #11  
Old 04-14-10, 03:15 PM
Member
Join Date: Jul 2009
Location: Toronto
Posts: 1,174
Received 0 Votes on 0 Posts
One thing you can do if you need to but a check valve in the cold, is to drill a very small hole in the blade (paddle)of the valve. This will allow the pressure to bleed back to the street at a reasonable rate, while stopping flow and heat migration.
That will last one h*ll of a lot longer than todays expansion tanks do.
 
  #12  
Old 04-14-10, 03:21 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 1 Vote on 1 Post
Thanks for checking that Mike! In addition to the meter itself, some homes where high city pressure exists may also have a pressure reducing valve on the water line into the home... and I'm pretty sure that all of these have check valves.

Still, tank or no tank, this heater reportedly only developed this problem 2 weeks ago after working well for 4 years...

And yes, this is a water heater post in the boiler forum, but we're bored, so I decided to leave it for now.

Even further off topic, I would say that all private wells have a foot valve of some sort.
 
  #13  
Old 04-14-10, 04:22 PM
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
Originally Posted by NJ Trooper View Post
some homes where high city pressure exists may also have a pressure reducing valve on the water line into the home... and I'm pretty sure that all of these have check valves.
For cities with elevated water tanks and no big hills (like where I live), the main pressure (psi) ought to be the height of the tank(s) (ft) divided by two. My water pressure generally runs at 60 psi, so the storage tank must be about 120 ft high? I don't know for sure, but assume that cities with elevated storage tanks out here on the prairie don't have pressure reducers at the house.

Naturally, I have a pressure gauge permanently mounted on my city water supply. Interestingly, the pressure bounces around about +/- 5 psi, probably because of the pressure drop in the mains (we are about 0.5 mile from the nearest elevated storage tank). Our water pressure typically runs at 60 psi, but just now at 6:00 pm on Wednesday, it was clear down to 55 psi. Probably people coming home from work, showering, flushing toilets? I need to check it on a workday around 7:00 am, but I'm not usually up quite that early

If in the future there is a major fire in town, I intend to monitor the water pressure - just as a curiosity. I could also do it when the water department flushes their water lines through fire hydrants.
 
  #14  
Old 04-14-10, 07:10 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 1 Vote on 1 Post
Interesting... never have thought much about elevated tanks as there aren't all that many around here in NJ... there are a few though.

Still, there must be pumping stations, and the tanks are simply 'reserves', much as a private well tank would function... something has to pump the water up into the tank, right?

But yeah, the calculation of pressure is close enough for gummint work... and if the pumping stations did deliver more pressure, the elevated tanks would overflow, right?
 
  #15  
Old 04-14-10, 08:01 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,482
Received 25 Votes on 19 Posts
I live in hilly country so most of our water tanks are built on the ground but they may be quite high. Some of them even have observation areas for the general public to look over the city. These tanks are often called standpipes by the water authority and they may have a ground level reservoir next to them. These reservoirs were originally not covered but after 9/11 the possible terrorist threat was such to have them lidded.

The tanks are filled by pumps that work either singly or in multiple according to the water demand. Most of the pumps are variable speed and in the "olden days" they used a magnetic coupling between the motor and the pump to vary the speed. Today they use direct drive pumps with a variable frequency drive on the motor. The goal is to keep the tank at a more-or-less constant level, about 90% of capacity, during normal usage.

While about 60 psi is a "normal" pressure for city water supply to homes I personally know of areas in Seattle that have city water pressure exceeding 100 psi. There are also areas where the pressure is about 30 psi or less. I don't know about other areas but in Seattle it is fairly easy to guess at the nominal water pressure by looking at the fire hydrants. Those with a red top have 30 psi or less, those with a yellow top are between 30 and 60 psi and those with a green top are in excess of 60 psi.

In the city of Renton (a bit south of Seattle) they get about half of their water from wells (Seattle is all from mountain watersheds) and there are places in Renton that have water mains operating at more than 200 psi. Of course they have pressure reducing valves periodically placed to feed the lower-pressure neighborhood distribution mains at closer to 55psi.

Where I used to live, approximately 10 miles north of Seattle, the water pressure would vary quite a bit, from a low of about 40 psi to a high of about 70 or 80 psi over a 24 hour period when the city was doing maintenance on its single water tower or pump station. Back then I had a recording pressure gauge (chart recorder) and it was quite interesting to see the variation and the time it occurred.

Where I now live (about 10 miles northeast of Seattle) I have a simple water pressure gauge with a highest reading hand that I leave connected at all times. The nominal pressure is about 55 psi but the highest reading hand has occasionally gone to over 70 psi. A few years ago the city replaced the water meters with ones that could communicate with a handheld data logger to eliminate the mistakes made when manually reading and recording the meter reading. I'm pretty sure these meters have a built-in check valve and the only reason I don't absolutely need an expansion tank on my water heater is because I rarely go for more than maybe three hours without using some water (even if it is only the icemaker in the refrigerator) and also because I installed huge air chambers when I replaced my bathroom shower valves and installed a laundry tub.

The study of municipal water systems can be fascinating.
 
  #16  
Old 04-16-10, 06:48 AM
Member
Thread Starter
Join Date: Nov 2007
Location: IL, USA
Posts: 42
Received 0 Votes on 0 Posts
I apologize for posting this on the wrong forum. I didn't realize that there's a separate forum for water heater.

I bought and screwed the pressure gauge onto the water hose draining pipe of the water heater. It's reading 70psi. I lifted the relief valve lever and flushed out some water. I closed it back but somehow it's leaking even more now. Is it safe to assume that the relief valve is the problem since the pressure is only 70 psi.

Thanks a lot for all your inputs. I appreciate it.
 
  #17  
Old 04-16-10, 07:27 AM
Member
Join Date: Sep 2009
Location: U.S. Midwest
Posts: 1,340
Received 0 Votes on 0 Posts
Originally Posted by canon2 View Post
Is it safe to assume that the relief valve is the problem since the pressure is only 70 psi.
I would just go ahead and replace the T&P valve. The Btu/hr rating of the new valve should be at least as high as the original valve.
 
  #18  
Old 04-16-10, 07:46 AM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 1 Vote on 1 Post
Leave the gauge on for a few days and see what the peak pressure is, but yeah, I tend to agree with Mike... sounds like it might be a problem with the valve.
 
  #19  
Old 04-17-10, 06:52 PM
Member
Thread Starter
Join Date: Nov 2007
Location: IL, USA
Posts: 42
Received 0 Votes on 0 Posts
I replaced the relief valve yesterday. However, I noticed this afternoon that there was a little drip of water on the floor. I got me a new pressure gauge (I guess the first one was faulty) and tested the outside spigot. The reading is close to 80 psi. I'll test the water heater again later on.

Thanks for all the help.
 
  #20  
Old 04-17-10, 07:30 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 1 Vote on 1 Post
I don't think a 10 PSI fluctuation is out of the ordinary... but still, the relief valve is probably set to 150 PSI. Leave the gauge on for a few days and let it read the peak pressure. It might be going high overnight, or when the burner kicks on and heats the water.

Did you take the water temperature? remember that valve is a combination temperature and pressure part.
 
  #21  
Old 04-21-10, 08:29 PM
Member
Thread Starter
Join Date: Nov 2007
Location: IL, USA
Posts: 42
Received 0 Votes on 0 Posts
So far the pressure gauge reading of the water heater is 80 psi and the highest/peaked reading is 90 psi. I haven't taken the water temperature yet. I'll do it next.
 
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
 
Ask a Question
Question Title:
Description:
Your question will be posted in: