I'm going away for a week and I wanted to put my gas HW heater in
"vacation mode". In the past I noticed that even if I turn down the T-
stat dial, it still comes on, although the water temp is lower than
the usual 140 deg. Am I better off just putting the gas valve to
"pilot" instead of "on", that way I know for sure it will stay off?
I always turn mine to pilot when away for an extended period. I also
shut off the main water supply valve to the house as a precaution.
Some people will argue that allowing the tank to cool down subjects it
to stress and will result in earlier failure, but I've never seen that
backed up by an actual data. Also, the temp swing from 130 down to
65 isn't that large compared to other temp changes with a lot of
equipment that doesnt' cause failure.
The tiny bit of heat from the pilot helps keep a small air
flow. Holds down humidity, so it doesn't rust out. Or, so
Same deal with furnaces. Pilot light models, leave the pilot
light on at all times.
I seriously doubt that this makes any difference. Turning off the pilot, even
for a week, and the water won't even get down to room temp. Even if it does, it
shouldn't be an issue. High efficiency water heaters and furnaces shut off the
pilot themselves, and they don't have a problem.
I suspect that the burning pilot could create more corrosion problems, as the
resulting moisture from the pilot condenses on the cooler metal it can't really
We have a vacation setting on ours and an electronic pilot. Ours in located
in the garage and the water is distributed through the attic. We live in
Vegas and went away for 4 days so I turned it to the vacation setting.. We
went came back, I forgot to turn it back up. We both showered and didn't
notice for three days, since there is so much heat in the garage and attic
during the summer here. But it's a dry heat <grin> 110 today.
I always turn it off--why run it---been doing it for years and have never
seen any adverse effect. Additionally, I also shut off the house inlet
water valve (even for an overnighter). Once OK, but twice shame on me---I
experienced a failure (toilet) when away on vacation a few years ago (opened
the front door and heard water running); 4 months and $25,000 later the
house was back to normal. Two bathrooms completely destroyed and while
things were being restored had to wash and shave in the kitchen sink, use
the toilet in a downstairs bathroom and shower in an upstairs bathroom for 4
months. What would you rather be---paranoid or sorry?
My father twice filled his finished basement with water while he was
away on vacation. The neighbors noticed the water pouring out of the
little windows near the basement ceiling. You'd think he would have
learned the first time.
What I do is turn the water heater down to the lowest setting and turn
the water off to the house even if I'm gone for a night. It only takes
me less than a minute.
So here is my theory...
Even if you have a pressure regulator on the cold water input to your
home, most of these have a back flow prevention....so if you use some
hot water, then stop using water, all the spigots are closed. Then
when the water heater comes on to re-heat the water, the pressure
builds and cannot back flow through the regulator so it just builds
and builds. And when you go away on vacation, the cycling on and off
of the heater with NO use of water allows the pressure to build more
then usual. So I always turn off the water heater when going away
for a while just to keep the pressure from being able to build.
The best answer is an expansion tank or pressure relief valve. I'm
surprised this pressure build does not cause more problems then it
Of the houses I have seen personally, probably less than 1 in 3 had
basement drains, unless you count the sump pit and pump. You can only
have floor drains if there is some place for water to go, and in much of
the country, the sewer exit is halfway up the basement wall.
Having said that, I think these people who turn WH and water supply off
for anything short of an extended trip, are deluding themselves. The
odds of a catastrophic failure while they are gone are so low, that the
additional wear on the valves probably cancels any benefit. Life is too
short, etc. Just keep the house in good condition, and don't worry about it.
Are you nuts?? You're worried about the wear and tear of some valves (mine
are all ball valves now and have never had to replace any of them) that
probably only get exercised several time a year at the most. Low odds or
not--how many catastrophic failures are you willing to put up with? Once is
enough for me.
BTW, how many faucet failures-kitchen, bathroom, etc.--have you experienced
and over what time frame between them? Based on your comment, perhaps you
ought to leave them on all the time instead of turning them on and off.
With respect to the following comment:
"What I do is turn the water heater down to the lowest setting and turn the
water off to the house even if I'm gone for a night. It only
takes me less than a minute"
Now that is a potential catastrophe in the making. If you have an expansion
tank, no problem. If you have a relief valve on your water heater (T&P
Valve), no problem (if it works per design intent)--just some water on the
floor. If there is no relief valve in the system (or it doesn't work
properly) then you have a scenario that can result in a failure of the
weakest link in your plumbing system----the water heater, a solder joint
washing machine hose etc--. Water is not incompressible. It expands as
it's temperature is increased--Example: Auto cooling system: every car today
has an overflow tank to catch the coolant that comes out of the radiator as
it is heated and expands. Almost all radiator caps are set to crack at 15
psi before they open. Without doing the math, increasing water temperature
from room temp to about 140+F can increase the pressure of a closed system
(no relief valve/expansion tank) to the 1000+ psi level. That's high enough
to start breaking things. If you're interested:
Delta P=BM*(Delta V)/V
Where: Delta P is the change in pressure
BM=Fluid Bulk Modules
Delta V=Change in fluid volume (expansion as it heats up, can be calculated
based on change of specific gravity vs temperature
V=Volume of fluid in the closed system
Granted, compressibility is not an everyday concern but it is an extremely
significant factor in servo systems and can be the difference between a
stable or unstable system.
My neighbor came back from a 4-week vacation with $34,500 damage due
to an ice-maker line leak. The damage included furniture, walls, the
ceiling below, etc. Now, he turns off the water main before
I have a well and electric water heater. I always turn the breakers off
when leaving overnight. This means I could get whatever is in the tank and
no more water. Moved in this house about 4 years ago.
The other house was fed by a comunity well and a gas water heater. It was
built around 1965. The water pipes started getting pin hole leaks about 10
years ago. I had the pipes replaced after patching them about 5 times over
a couple of years.
After moving and while trying to sell the house I left the water on. Came
in after being gone 2 days and found one of the hoses of the washing machine
had broken and was leaking very bad. Just lucky it was a house where the
washer was in the little room of a carport so there was no real damage done.
I then cut off the water and turned the water heater to pilot unless I was
at the house.
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