water running when nothing is on

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by crazebstrd, Sep 5, 2008.

  1. crazebstrd

    crazebstrd New Member

    Messages:
    13
    I had new water heater installed last month along with a 2 gallon thermal expansion tank which something I didn't have before. The plumber said that the tank was required by code. Ever since the installation I've noticed that the water continues to run slowly at the meter sometimes for several minutes after the water is turned of at the fixture. Longer after heavy usage. This is something that wasn't happening before. I contacted the plumber, State water heater company and the water company none of them offered any helpful answers. I just replaced the the water pressure reducer valve because I had a leak at the pressure relief valve on the water heater. This stopped the leak but I still have the water continue to run at the meter after water usage. The only way I can get it to stop is if i shut off the valve above the expansion tank and water heater. Then, the water shuts off right away but as soon I open that valve the water continues to run. The expansion tank is a Wellsaver LPT-2 2 gallon tank and it is installed right above the water heater right after the shutoff valve. Can anybody tell what is going on here and is this something I should be concerned with? I can't find much information on the tank. Do they require regular maintenance? Is there anyway to check if it working properly?

    thanks
  2. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,382
    Location:
    Yakima WA
    That is a strange one! I can't answer why the water continues to run after everything is off, but I can answer a bit about the expansion tank question. Let me start with a question. Did you use a pressure gauge and match the pressure regulator valve pressure to the expansion tank? They should be equal. And, just so we are using the same language to describe things, what you are calling the pressure reducer is usually referred to as a pressure regulator or PRV, and what you are calling the pressure relief valve is usually called the temperature/pressure valve or just T/P. You are correctly describing their functions, but there could be some confusion. The expansion tank is installed between the PRV and the water heater in the cold water supply. The tank has a rubber bladder that, just like everything else will fail. You will know it failed when the T/P valve trips and leaks water. There isn't much maintenance to do, just periodically check the pressure. It should stay where you have it, so if it changes, that may be a sign it is beginning to fail. Wish I could give some assistance on the other problem, but probably some of the pros that hang around the forum will chime in.
  3. crazebstrd

    crazebstrd New Member

    Messages:
    13
    expanstion tank

    Thank you for your prompt reply. I'm fairly certain that the plumber did not check the pressure in the tank or the water pressure to see if they matched. I don't own a water pressure guage so I can't check that. I just had new prv installed and it is factory preset to 50psi. Do I check the tank with a regular tire guage to see if it matches 50psi? Thanks in advance.
  4. crazebstrd

    crazebstrd New Member

    Messages:
    13
    expansion tank

    Just checked expansion tank pressure. I is at 54psi so I'm guessing that's fairly close to the factory preset 50psi on the PRV.
  5. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    It sounds like as the flow of the water reduces so does the pressure going through the pressure reducing valve. It will reduce untill it reaches the pressure setting of the valve. I am going to guess that the water is flowing through your PRV at a much slower rate when it is close to its pressure setting than when the pressure differences are greater as they are while you are using water.

    It does eventualy stop...yes?

    It is how your PRV is operating at low flow.
  6. crazebstrd

    crazebstrd New Member

    Messages:
    13
    expansion tank

    Yes, it stops. How do I charge the tank to the correct pressure? Do I need to take somewhere to get it done or can I just use bicycle pump?
  7. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    Why do you want to change the tank pressure...it has nothing to do with what I just explained. Your PRV s the valve installed near where the water enters the house.

    It controls the pressure on the house side of it.
  8. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    The pressure on the tank bladder will read its set point or the water pressure as long as the system is under pressure.
  9. crazebstrd

    crazebstrd New Member

    Messages:
    13
    expansion tank

    I was told by State water heater that the air pressure in the tank should match the pressure coming into the house. I checked it and it is below the 50psi preset on the PRV.
  10. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    You need a pressure gauge to check the water pressure setting first. While the pressure setting should be 50 from the factory I have found that they are many times way off.

    You also don't know what the plumber may have done.

    Tanks are preset at 40 PSI. You need to call the plumber back and have him charge / check the tank if it is off.

    Hack plumbers will many times just install the tank without setting the pressure to match the house pressure...I like my tanks to be 1-2#s lower than the house pressure.
    Last edited: Sep 6, 2008
  11. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,382
    Location:
    Yakima WA
    Never guess or assume what the pressure is in anything. A basic gauge can be purchased in any hardware store or plumbing supply for under $15. If, and I stress IF, the pressure in the expansion tank needs to be increased, Watts advises a bicycle pump. The actual volume of air needed is quite small so it would be easy to rupture the tank's bladder using an air compressor.
  12. crazebstrd

    crazebstrd New Member

    Messages:
    13
    expansion tank

    You were right about hack plumbers. He just put the tank in without checking the the water pressure coming into the house or the pressure in the tank. You would think a master plumber who installs water heaters for a living would have taken the time to do this. Anyway, I've pretty much had it with this guy after calling him back for one thing or another since the tank was installed so I decided to do it myself. I went to Home Depot and and picked up a water pressure guage for 10 bucks and a hand pump for 9 bucks. I checked the pressure at the hose bib and it was off the 50psi preset on the PRV so I tweaked it a little until it was at 50psi. Then, I shut down the water and drained the water heater a little to relieve the pressure. I removed the expansion tank which was installed directly above the water heater blower control box which I'm not to happy about. In his defense there wasn't much of an option this was the only exposed pipe in the finished basement. But, he could have angled it out away from the blower. I guess I will have to get some kind of angled adapter to remedy that situation if possible. Luckily the pump I bought was pretty sturdy, a Husky, so I was able to pump the tank up to 50psi. (this was not easy, it took some pretty hard pumping to get it up to that pressure....imagine pumping up a truck tire with bicycle pump and you'll get an idea what I mean) Anyhow, I put the tank back onto the cold water inlet to the water heater which has the tank in a horizontal orientation, hopefully this it ok positioning. I turned the water and water heater back on and voilla, no more running water after water is turned off.

    Thanks for all your posts and if you can think of anything else to add or ask, please do.
  13. crazebstrd

    crazebstrd New Member

    Messages:
    13
    expansion tank

    Since the tank is installed horizontally, do I need to support it to take pressure off the fitting? If so, how is this accomplished. I received no instructions with the tanks since it was installed by the plumbing contractor and can't seem to find any information about them online. The tank is a Wellsaver LET-2, 2 gallon expansion tank, The water heater is a State Select 40 gallon gas powervent model. Any info would be greatly appreciated. Thanks again.
  14. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States
    Water Heater

    Go Pick Up Some Plumbers Tape And Drywall Screws Take 2 Wraps
    Around Tank And Anchor With Screws To Over Head Beams Or Anything Above That Will Support Weight Because You Are Right
    If That Bladder Fails The Tank Will Fill With Water And Break At The Fitting
  15. crazebstrd

    crazebstrd New Member

    Messages:
    13
    Thanks for replying, Mac. I'll give that a shot.
  16. Winslow

    Winslow Plumber

    Messages:
    450
    Location:
    Hawaii

    You need to verify system presure with a gauge on a hose bibb. Don't assume it is 50 lbs based on a stated preset rating. The PRV adjusts pressure relative to the incoming pressure, therefore any preset pressure rating would be relative to incoming pressure. For instance it may be preset for 50 lbs based on incoming pressure of 80 lbs. If incoming pressure is actually 100 lbs then it would reduce it to 70 lbs.
  17. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Ummm not quite...
    It functions as a regulator and the pressure would be at the set point unless the supplied pressure is lower than the set point.
  18. crazebstrd

    crazebstrd New Member

    Messages:
    13
    Redwood, from everything I've read I'd have to agree with you on that.
  19. hltibbs

    hltibbs New Member

    Messages:
    1
    Location:
    Ohio
    Low water outlet after installing LET-2 expansion tank

    I just installed a LET-2 on a 50 gal electric heater yesterday and now the tenants are complaining of very low water output at the faucets. The inlet and tank pressure are within a few pounds of each other (50 +/-).

    What would cause this low hot water output and how do I fix it?
  20. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    It could be a number of things.
    The valve you shut the water off with may have broken and not opened all the way back up.

    Or the aerators on the faucet may have plugged with debris dislodged while you were working on the system.
Similar Threads: water running
Forum Title Date
Plumbing Forum, Professional & DIY Advice Cold water line running hot Apr 2, 2014
Plumbing Forum, Professional & DIY Advice Running 3/4" pex to water heater in 2X4 wall Mar 25, 2014
Plumbing Forum, Professional & DIY Advice Where does the water come from? Water keeps running in laundry room. Pls help! Dec 28, 2013
Plumbing Forum, Professional & DIY Advice Running out of hot water with a 60G tank Dec 8, 2013
Plumbing Forum, Professional & DIY Advice Hot water release valve running 24/7 Nov 6, 2013

Share This Page