Whirpool 50g gas heater thermal expansion problems

Discussion in 'Water Heater Forum, Tanks' started by Agent Black Jack, Jul 27, 2020.

  1. Agent Black Jack

    Agent Black Jack New Member

    Joined:
    Oct 8, 2013
    Location:
    Las Vegas
    Whirpool 50 gallon gas water heater (N50t91-403) : 8 years old
    Normal household psi: 50 psi
    Water expansion tank: 2 gallon

    1.) Couple weeks ago, noticed high psi 100+. I figured the thermal expansion tank failed, so I replaced it. Didn't solve issue. Plus, the original te tank looked good.
    2.) The honeywell thermostat is new. Blinks normally. Although I have to turn the dial down to near vac setting otherwise water climbs above 120+ degrees.
    3. Looking through the peep glass, I notice a low baby flame is on. Every time I randomly inspect, it's on.
    4.) Cold water feels warm now.
    5.) I do flush it annually, but still look gunky in there.

    What could be the problem? Thanks.
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I think that is perfectly normal. A 4 gallon tank would rise less. But if you keep the peak pressure under 130, that is fine. There is somebody who thinks otherwise. He is overly extrapolating his reference IMO, but neither of us is a pro.

    Set the air precharge to about 52 psi. This allows for the pressure rise in city water that normally happens in the night. So you would ideally set the precharge to the normal peak from the city, but who wants to stay up and monitor for that?
    Sounds like a pilot light. However I would think that a WH with an electronic control that blinks would not have a pilot light. Edit: http://www.whirlpoolwaterheaters.com/support/N50T91-403 says your WH has a pilot. One less thing to worry about.

    Can't blame the WH for that. Does the piping go through the attic?

    Does the water that comes out look gunky? How do you flush?
     
    Last edited: Jul 27, 2020
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  4. Agent Black Jack

    Agent Black Jack New Member

    Joined:
    Oct 8, 2013
    Location:
    Las Vegas
    It's never happened before, at least not this severe. This is why I noticed something was wrong when I start using the faucets inside and water gushed out forcefully. Then, I check again a few hours later and noticed the psi is high again.

    The precharge is set to 51, according to my air gauge. I've always done this and never encountered this issue before.

    You're right, it does have a pilot.

    House has copper plumbing and didn't notice any in the attic. Cold water did get considerably warm when this all started happening. Or, it could be purely coincidental considering it's summer time and hot. I figure it's worth mentioning.

    Yes, lots of mineral deposits. Some of it looks like a soft gelatin like substance. Mainly crusty minerals. I flush it by opening the hot water faucet, close the cold water to the heater and opening the drain valve. Then, when it's almost empty I open the cold water valve to heater, back and forth closing and opening trying to let the pressure water squirt inside. I don't know if this is efficient or not, but I see gunk come out whenever I drain. Also, I replaced the stock drain valve a few years back with a ball valve to let big mineral chunks through. I have a snake camera that mechanics use and looking inside, I still see sediment in there. Does it have to be completely free of sediment inside?
     
  5. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Do you have a PRV (pressure reducing valve) for your city water? If you turn the WH to vacation mode, the WH will not make the pressure rise. If the pressure then rises, it is not the WH. A PRV would explain a pressure rise without the WH.

    Do you check that with the water pressure zero?

    You could try turning off the water into the WH, and see if the cold water becomes no longer warm.

    I think that is from the aluminum in your anode. Do you replace your anode ever? Do you get an H2S ("sulfur") smell in your hot water?
     
    Last edited: Jul 27, 2020
  6. phog

    phog Active Member

    Joined:
    Jul 29, 2017
    Location:
    Rochester NY
    If you have a main service valve & fixtures that all seal up 100% against pressure, you could turn the main service off for a couple hours. Observe how high the pressure gets. Whatever pressure you see with the mains off is due to the water heater. Anything in excess of that is coming from the service main & you could have a PRV that needs rebuild/replacement.
     
  7. Agent Black Jack

    Agent Black Jack New Member

    Joined:
    Oct 8, 2013
    Location:
    Las Vegas
    I do have a PRV. It's set to 50 psi. PRV is 1.5 years old.

    Yes. What I did was turn the cold valve off and let the pressure out of the water heater tank before I check the Thermal tank. Plus, when I removed the old one from the system, the bladder was still 51 psi.

    I will try it.

    I have replaced anodes in the past. However, with this water heater, I never changed it. No sulfur smell.
     
  8. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Good chance that PRV needs re-building or replacing. If the pressure rises with the the WH set to vacation or pilot and you don't use water, that would indicate the PRV leaks pressure through.
     
    Jeff H Young likes this.
  9. Jeff H Young

    Jeff H Young In the Trades

    Joined:
    Feb 27, 2020
    Location:
    92346
    replaced mine 2 years ago rebuilt it few mothes ago. pressure creeps up slowly
     
  10. Agent Black Jack

    Agent Black Jack New Member

    Joined:
    Oct 8, 2013
    Location:
    Las Vegas
    Yes, turned out it was my prv. Can't believe it failed so soon. 1.5 years old is too soon. I'm going through these valves like every 2-3 years. This sucks.

    Side note, hot water temp coming out of faucet is 120 degrees after running for a few minutes. Should be good right?
     
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    What is your incoming water pressure? Most PRV's have a maximum differential pressure drop across them. If your supply pressure is quite high, you might need two of them in series to drop the pressure stepwise, keeping each within their limits. That's unusual, but possible.
     
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