Bob wrote:
On Feb 14, 1:04 pm, "George" wrote:
On Feb 14, 12:08 pm, "Bob" wrote:
Ok, I have a cabin in the country. Because the propane WH is
getting close to being old, when I'm not going to be there for a
week or so I turn the water inlet valve off and the thermostat to
pilot. That way if it leaks, the water spilled will be limited to
40 gallons.
Anyway, when I turn the water valve back on after a week or two,
there is a good amount of air in the tank and hot water lines.
There is no water around the heater. There is no indication of
rust on the tank burner or tank bottom. I crawled under the cabin
and there is no water spotting on the subfloor, nor water on the
vapor barrior.
So I'm puzzled. Where is this air in the tank coming from? I'm
talking about air/water spewing for up to a minute. First thought
was a leak and second thought was volume contraction due to
cooling. But that much???
Bob
Cooling water heaters suck
It's probably "sucking air" when it's off.
For a demonstration try this fun experiment, get an empty gallon
plastic milk jug and put a 1/4 cup of water in it, now stick it in
the microwave (with the lid OFF) just long enough to get the water
good and hot, now take it out and screw the lid on and let it cool
off (you can set it in the fridge if you want fast results)....see
what happens to the jug??
Cool huh?
When your water heater cools it does the same thing...only it is
stronger than a plastic jug.
George
Ok, I can buy that. But with the faucets closed, where's the air
coming from, the pressure relief valve backflow? And where is the
water that is replaced by air going?
I would guess either the
PR valve or the air could be coming from the
water. Water does absorb air. How much air depends on the temperature and
pressure. Have you not noticed that sometimes when you fill a glass with
water (during the winter) it is milky looking. That is air that was in the
water. The time of year and the change in temperature of the water may be
forcing dissolved gasses.
--
Joseph Meehan
Dia 's Muire duit