On Mon, 15 Dec 2008 12:54:06 -0700, termtests wrote:

We're going through a nasty cold spell right now (-13F/-25C to
-22F/-30C) and it's expected to last for quite a while yet. And my
coworker suggested that I turn the main water valve off in the house
before I leave in a couple of days for a vacation.

I will still have my furnace running when we leave for vacation, but I
plan on having it maintain a temperature of 60F/15C while we're away.

Is turning the main off still a good idea? Also, should the furnace
be set at a little higher temperature while we're away when taking the
outside temperature into account? Thanks for your time and courtesy.

If you're going to turn off the water, and open a basement faucet for
the water to drain, you shoould open an upper floor faucet for air to
enter the pipe. Both cold and hot water. (Someone here once
explained how hot water pipes burst before cold water pipes do. No
kidding. It made sesnse.)

This seems to imply draining the water heater, and i guess that
doesn't cost any money becuase the water would be cold in a few days
anyhow. When I went away for two months, not nearly as cold as your
weather, i had no water heater so it wasn't an issue. You should have
a pan and drain pipe for your water heater anyhow, so maybe don't
worry about that. If it's in the basement, how cold will it get
without heat. And if it freezes and cracks, it's about 600 dollars
maybe but the odds of this happening are 1 in 2000?, so that's only 33
cents worth of risk.

And if you're going to do all this, you might as well pour anti-freeze
in your traps. I think for me it took a half-gallon to do 3 toilets,
5 sinks, a shower and a bathtub. That's almost a cup in each, which
might be more than i needed. I was trying for a 50/50 mix with the
water. It was almost the last thing I did before I left, maybe saving
a cup of anti-freeze to use in the last toilet. Flush the toilets
before pouring in the antifreeze.

I hustled and this all took maybe 20 minutes (no time spent on water
heater), and when I got home I only had to close two faucets and turn
on the main valve. Oh, and I would have had to close turn on the
water heater, if it was full of water.