I'd like to thank Tom for his answer to my first question, and ask one more. If I turn my hot (gas) water heater to "pilot" will it be on the lowest setting or do I have to turn the temp. knob down as well... also will it be OK if I have turned the water off at the Main?

I would shut down the water main... then set the temperature dial (gas valve) to VACATION setting (see pic. hopefully you can read it... words on dial are hot (left), warm (middle) and vacation (bottom right)). The dial should say vacation right on the front... leave pilot button alone. If your gas valve does not look like this one, then just set to lowest setting on dial (will say pilot)... that should do it for you.

Someone may say that you need to open lines, etc... but you don't... just shut off water main, and then reduce dial to vacation setting or lowest possible setting

Be sure to note the exact position (could mark with marker) of the big red dial before moving it so you can set it back to exactly that spot when you get home.

If this helped, please RATE THIS ANSWER. Thank you.

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Originally Posted by massplumber2008

I would shut down the water main...then set the temperature dial (gas valve) to VACATION setting (see pic., hopefully you can read it). The dial should say vacation right on the front...leave pilot button alone. If your gas valve does not look like this one, then just set to lowest setting on dial...that should do it for you.

Someone may say that you need to open lines, etc...but you don't...just shut off water main, and then reduce dial to vacation setting or just keep pilot dial set where it is.

Be sure to note the exact position (could mark with marker) of the big red dial before moving it so you can set it back to exactly that spot when you get home.

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Mass Plumber: I do NOT have a "vacation" setting - I have off, on and pilot. I have marked where I always have the temp. set.

Perfect then... you did perfect. Just set to pilot then. You could have just turned the temp. dial to lowest setting... but what you did is fine, too Good for you... You should be all set 'till you get home... Enjoy your vacation.. and be sure... NO FLOODS when you come home! Take care!

Yep you got it straight, shut down the main and move your dial to pilot only. You could move it to off but that may allow humidity to build up and rust parts of your heat exchanger so in most climates pilot is better. If you happen to live in Saudi Arabia then off is fine.

Massplumber:

There is a reason why I would recommend leaving one hot water valve open, even if it's a little bit. If you just turn off the hot or cold water, the water in the hotwater tank will start to expand as it cools. It can't go against the main, so it goes against the pressure relief valve.

I'd rather not have that valve start to leak.

Hence, my recommendation is to open a hot water tap, so that if the water in the tank expands, it has somewhere potentially non-destructive to go assuming no cold water expansion tank in the system.

Just so I remember; I open the laundry sink; close the cold water to the hot water heater and go to pilot. The cold water main is at the other end of the house, but that line isn't usually turned off.

So, Massplumber, care to adopt my view?

Nope.. sorry Ron.

Hot water expands as it is heated not when it cools unless we are talking below 4 degrees celsius and then yes, water will expand again to solid state (ice). Water is the only liquid that does that. BUT we are not talking about near freezing temps.. we are talking about a water heater with a pilot lit under it (I won't even go into open vs closed systems).

Further, now think about this... the water in the water heater is used to expanding to accommodate really hot water... you know, water heated from street supply temp (45 to 70 degrees) to 120F degrees or so... and it can sit for days/weeks without any pipe opening... or temperature and pressure relief valve going off. And that is under rather extreme conditions.. yes? Do you really think that the pilot flame will create expansion compared to that?

People do need to open and drain lines if winterizing, in fact, they need to blow the lines down if winterizing so they can be sure pipes are winterized.

That all being said, I have noticed people online here telling people to shut off heaters and open pipes... I have not said anything... tried to mind my own... but since YOU asked... Do you care to adopt MY view now... ;)?

Let me know. Talk soon.

Ignore my signature... just added that... can't seem to get rid of it


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the water in the hotwater tank will start to expand as it cools. It can't go against the main, so it goes against the pressure relief valve.

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This statement would be true if only KISS had the word "heat" instead of cool. This is exactly what happens when you have a checkvalve or backflow preventer installed on your water service.

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I have noticed people online here telling people to shut off heaters and open pipes... I have not said anything...

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Well, I'd have said something if I would have caught it. Guess I'm going to hafta start checking the answers a little better. Regards, Tom

Well, I did some more research. It appears that water behaves in a peculiar way. It both expands and contracts with increasing temperature. The transition point is about 4 deg. C. So, when a water heater heats, the water expands, when it cools and it's near freezing it expands.

Therefore, mp and speedball are correct: You don't have to open the hot water tap when you go on vacation.

Thanks for the eye opener. I learned something today.

PS:
Links:
http://www.wvdhhr.org/phs/water/Thermal_Expansion.pdf
Why Does Water Expand When It Cools?

So, if I am going on vacation for 1 week. I set WH to vaction or pilot depending on the type, but do I really have to shut off the water for 1 week? I do have a neighbor with house access and he will be checking things.

If only going on vacation and not winterizing the place then there is no need to shut the water supply off... just makes sense to set to a vacation settting to stop from heating the water!

We recommend shutting the water main if it is possible... just in case something goes wrong with pipe,connector, or the water heater, but if you have a neighbor that may not work for you.


Mark

Mark nailed it down, I would recommend to leave one hot water valve open in the house, Thanks.

John

I have a Kenmore gas hot water heater. From reading all these questions is it safe to assume that when I go on vacation I can turn off my water and just turn my hot water heater to the vacation setting?
I don't want to risk pipes breaking or leaks, hence turning off my water. Also don't want to spend money to heat the water in my hot water heater when I am not home.
Seems fairly simple to turn off water and turn setting on heater to vac. Does it matter whether I turn off the water before or after I change the setting on the hot water heater?

Thanks for your help. I am a new homeowner and am trying to avoid causing myself complications while I am away.

Hi mrstan and welcome to The Plumbing Page at AMHD.com.

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do I really have to shut off the water for 1 week?

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Shutting off your water when you go on vacation is the cheapest insurance you will ever buy. If you spring a leak it could cost you thousands before your neighbor could get in and check it. Set your water heater on vacation and turn the water off at the house. Have a great vacation! Tom

Hi - is 6 weeks too long to leave a gas water heater on "pilot"? (I intend to shut off the main and open a hot water tap and not drain the tank.) Thanks...

Water heater can stay on "Pilot" indefinitely. Yes turn off water at main but no need to open hot water tap.

The previous answers do not make sense to me. You are saying turing to "vacation" or "pilot" are the same thing? On my water heater they are two distinct dials. One controls water temperature, the other gas. So just turning one down is sufficient for turning off a water heater for an extended period?

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Originally Posted by mrstan64

So, if I am going on vacation for 1 week. I set WH to vaction or pilot depending on the type, but do I really have to shut off the water for 1 week? I do have a neighbor with house access and he will be checking things.

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No you don't have to shut the water off. But,it is a lot easier to turn water off than mop it up. Could run for 24 hrs.

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Originally Posted by chal08

The previous answers do not make sense to me. You are saying turing to "vacation" or "pilot" are the same thing? On my water heater they are two distinct dials. One controls water temperature, the other gas. So just turning one down is sufficient for turning off a water heater for an extended period?

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You can turn to pilot or vacation. Depending how cold it may get and how well insulated the tank is may make little difference.

I guess a question I have is if you have a 40 gallon tank and turn it to vacation and also turn off the water main and be gone for a 5 month period is this a safe thing to do? I mean being in vacation mode the water heater will still try to heat the water to some degree and being the main will be off and not be able to replenish the water supply is this going to hurt the water heater? I guess I just don't know how long 40 gallons of water will last with the limited heating cycle and burn someing up. Any help with this?