water heater drain

[anon125]

last year we moved into a 5 year old house.
the insurance people say if we go away for a month we have to drain the gas water heater.
we looked at the drain valve and there is a hole in the floor under it.
handy we thought - till we realised it just emptied into the crawl space!
we store stuff in there - the gas furnace keeps it dry.
In the crawl space under the water heater is a big black pipe - draining from the sinks etc we assume.
can we have the water heater drain into that black pipe?
it is several inches diameter.
tipe, alerts, and warnings appreciated.
trap? backflow valve?
thanks all

[hj]

If you just shut off the water to the house there is no way the heater could "rupture" and cause damage. If it were to develop a hole at the bottom, the air lock would prevent the water from draining out, and if it were to leak at the top, there would only be a small amount of water available to leak. Draining the water from the heater is more damaging to it, then leaving it full of water.

[anon125]

If you just shut off the water to the house there is no way the heater could "rupture" and cause damage. If it were to develop a hole at the bottom, the air lock would prevent the water from draining out, and if it were to leak at the top, there would only be a small amount of water available to leak. Draining the water from the heater is more damaging to it, then leaving it full of water.

thanks
thats what we told the insurer!
rules are rules we were told -
(even when they don't make sense!)
anyone could turn the water on again from the outside

[Ian Gills]

Hang on HJ. I have always been wary of shutting off the water to my gas water heater in case there is a leak (even from a faucet) that causes it to empty with the gas left on.

Shouldn't you turn off the gas to the WH too or am I just being paranoid?

[hj]

I have never seen a water heater start to leak and then drain itself when the system is shut off. I suppose it could happen. As far as the gas, if they are going to be gone that long, unless they are leaving the heat on, maybe they should turn the meter off so their's is not one of those houses that mysteriously explode due to a gas leak. In any case, there is no reason to leave it burning without anyone using hot water, so it should be turned to "pilot" or "vacation".