replacing thermostat/gas valve on water heater

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by vtlandlord, Jul 10, 2007.

  1. vtlandlord

    vtlandlord New Member

    Messages:
    5
    My water heater in the basement took a bath due to spring rains. The pilot wouldn't remain lit even after replacing the thormocouple so I had the whole thermostat/gas valve (propane) changed. It fired right up. But I would like to know something more.

    The old unit Unitrol had a larg red knob on top with a green cap on top with a screwdriver slot and it says main gas pressure, by which I assume that the amount of gas going to the main burner could be adjusted. The new control a bradford white doesn't have that feature. The diagram that came with it shows a "gas port" on the bottom of the unit. I looked and its something to be opened aparprently with a star screw driver. Is this a main gas pressure adjustment as on the unitrol? or is this just a place to attach a pressure gauge?

    thanks
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    When you say it had a bath.....
    Most water heater manufacturers specifiy that if a WH is submerged up to the level of the gas valve, it must be REPLACED. It is considered beyond repair. Too many "ifs"
  3. dubldare

    dubldare Plumber/Gasfitter

    Messages:
    286
    Location:
    MN/ND
    That port is for connecting a manometer to check manifold gas pressure.


    Ditto to what jimbo said.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,263
    Location:
    Cave Creek, Arizona
    valve

    If everything else is working correctly then the pressure adjustment does not do anything. It is there in case the gas company's pressure increases. It does not increase the burner size it is to keep it at the proper size. Newer heaters, yours must have been ancient, have a non adjustable regulator.
  5. vtlandlord

    vtlandlord New Member

    Messages:
    5
    Thanks everyone - these comments were very helpful.

    No it's not that old - well - I guess 8 years. Don't know what I was thinking of or whether I was thinking at all. Considering the price of the valve and installation and the age of the heater I should have just thrown a new heater in. Such is life.

    For future reference - physically as far as the location of everything on the new valve as opposed to the old everything is the same. And the identification on both indicated that the main burner pressure was 10 ". So would they be considered the same as far as btu output?

    And from above - is the pressure setting in the valve essentially a protection against the supply getting higher than that? After the gas goes through the propane company's regulator is the standard pressure 10" ? (and I assume the meaning of the pressure designation is that pressure would support a column of water 10" high?)

    I find this subject very interesting. Is there a standard textbook (not too deep) anyone can recommend pertaining to such gas applications?

    Thanks again.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,263
    Location:
    Cave Creek, Arizona
    pressure

    The secondary regulator on the LP system often is set for 13" and if your heater is labled like mine it calls for a minimum of 11" in the system so the heater's valve can reduce it to 10".
  7. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,397
    Location:
    Yakima WA
    For what it's worth. After Hurricane Katrina subsided and people began rebuilding, there were numerous warning that gas appliances that had been submerged, they were unrepairable and would have to be replaced. People were warned not to buy used appliances that might have come from the area. I have no expertise in this, but I'd point out that a malfunctioning gas water heater can be a bit more serious than just leaking. I know you don't want to buy a new heater at this time, but I would strongly urge you to consider it, especially with the age of the present unit being past normal life span. At the very least, discuss the potential danger with the gas company.
  8. GrumpyPlumber

    GrumpyPlumber Licensed Grump

    Messages:
    1,404
    Location:
    Licensed Grump

    A struggling family unable to afford a plumber...sure I could see the consternation, I've done water heaters at a discount. (it has paid back in droves with referral and repeat buz)
    A real estate owner, responsible for the safety of his tennants...which they pay for.
    I thinth I wilth bith my thongue.
  9. vtlandlord

    vtlandlord New Member

    Messages:
    5
    What what I understand from above the standard pressure after coming through the propane company's regulator is 13"?

    Also for an upstairs apaprtment, is the mass of the propae insignificant enough to not cause a significant pressure drop going up to the second floor?

    But getting back to the w.h. if the problem was that the thermostat/gas valve took a bath and that is completely replaced with a new one - even though economically I should have gone with an entire new system - what could be wrong with having the whole valve replaced? That's the heart of the whole system isn't it?

    Again, any textbook treatment of the subject that anyone can recommend? It would be nice to have sitting on the shelf.

    Also: if the pressure for the main flame is rated 10" on both the old and new units, does that mean that the BTU output is going to be the same, or no?

    Thanks to all who commented.
  10. Cbrigh2175

    Cbrigh2175 New Member

    Messages:
    1
    Can my Husband install our new gas water heater

    My Husband is wanting to install our new Gas 30 gallon water heater. Where does he get a soulder ? To soulder the gas. And This old Water heater is like 13 yrs old- How hard will it be to get it out of the bathroom closet? They tell me they are so heavy becuz of all the sediment - over the last 13 yrs, so we might need a dolly. Should i be worried? Will water gush out all over the floor? How do we pervent that. Set the old water heater in a Big trash bag ? How do you keep the hot water from burning you ? I know we hook up a water hose to it - and let it run outside . Can you give me any advice? Do you buy a 30 gal Bradford White Heater, or a Sears kenmore Roto Swirl one? And ----Is a 40 gal better than a 30 gal. ? Thank you
Similar Threads: replacing thermostat/gas
Forum Title Date
Plumbing Forum, Professional & DIY Advice Replacing a cartridge for an older Moen Monticello faucet Dec 10, 2014
Plumbing Forum, Professional & DIY Advice Replacing copper with PEX Oct 28, 2014
Plumbing Forum, Professional & DIY Advice Tricks to replacing tub overflow? Oct 28, 2014
Plumbing Forum, Professional & DIY Advice Removing a 3" Stack vent - Replacing with 4 - 1 1/2" vents????? Oct 17, 2014
Plumbing Forum, Professional & DIY Advice Replacing under sink, sweated, water shutoff Oct 7, 2014

Share This Page