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Davidlee64's avatar
Davidlee64
Explorer
Sep 29, 2018

What would cause air in water heater / lines?

Suburban SW6DE. Seems to work as it should. Serviced, new anode, electric element.
If I leave it turned off, run water, all is well. Turn on to have hot water, I get air through any faucet in spurts. Then eventually air is exhausted, and water flow is normal. After use, heater is turned off to save propane. When I anticipate need for hot water, I turn heater on 15 minutes prior to use. I get air from faucets again. This happens every time. At one point, I just left heater on, and got air every time I used hot water after 24 hours or so of non-use.
Does anyone have any ideas as to what may be causing this?
Thanks
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Sep 30, 2018
    It isn't steam.that would require 3 control/safety features to fail
    The normal temp t-stat/130*F, the high temp t-stat/170*F which has to be manually reset and the T&P Relief Valve/210*F--150#
    Then water heater would continue to heat and BLOW UP

    Trapped air...doubtful

    Build up of gas due to microbic action and the magnesium anode rod....ding, ding, ding
  • dougrainer's avatar
    dougrainer
    Nomad
    Sep 29, 2018
    Air pockets in the tank are usually a design problem of Atwood water heaters. Not Suburban's. Have you tried popping the outside pressure relief valve and see if it spits air also? I would open the Pop off valve and allow it the flow for about 30 seconds and then close it. Doug
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Sep 29, 2018
    I agree with the steam issue.

    Also are you on tanked water or city water.. Water pump could be sucking air.

    Frankly I can not think of anything that fits your symptoms 100%. usually I get air in the line only after a Drain and re-fill.
  • Dusty_R's avatar
    Dusty_R
    Explorer
    Sep 29, 2018
    2oldman wrote:
    wildtoad wrote:
    So how hot is the water coming out of the heater?
    x2. It is extremely hot?


    Could be steam, thermostat not turning off soon enough.
  • 2oldman's avatar
    2oldman
    Explorer II
    Sep 29, 2018
    wildtoad wrote:
    So how hot is the water coming out of the heater?
    x2. It is extremely hot?
  • wildtoad's avatar
    wildtoad
    Explorer II
    Sep 29, 2018
    So how hot is the water coming out of the heater? Use a meat thermometer or other to test the actual water temp coming out the closest faucet.
  • CloudDriver's avatar
    CloudDriver
    Explorer
    Sep 29, 2018
    A possible explanation is related to the fact that air dissolves in water. Dissolved oxygen is water is what makes it possible for fish to breathe. As water is heated the solubility of the air becomes less and the air comes out of solution and creates air bubbles. As the hot water is used new cold water with dissolved air enters the heater becoming a source for more air bubbles.
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Sep 29, 2018
    Usually, that is hydrogen buildup, but that's awfully fast for that to happen. Did it just start when you replaced the anode? If so, and if you go through anodes fast, you might try the aluminum anode.

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