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Open Roads Forum  >  Tech Issues

 > What happens if Water Heater is on & water tank goes empty?

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mezerr

London Ontario

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Posted: 06/07/12 07:06pm Link  |  Print  |  Notify Moderator

People says never to light the water heater with an empty tank, as you'll burn something out. So what if i'm having a shower, and the fresh water tank goes empty, thus emptying the hot water tank, eventually. I guess I then have to run out to the hot water heater, and quickly turn it off? Or does it sense there's no more water, and auto shut off?

And also, if it's on electric heat, and you notice there is no more hot water, or cold water (empty tank), what if you forget to turn the electric heater off?

I guess you've just gotta always be on the ball with the water heater? No Mistakes! ?

BobsYourUncle

Surrey, BC Canada

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Posted: 06/07/12 07:10pm Link  |  Print  |  Notify Moderator

You will lose pressure before the HWT goes empty.

The pump pulls from the fresh water tank. If it runs out, you will be in the shower with a sputtering shower head. There will be no more pressure pushing the water out of the HWT.

By the time you turn it off, towel off, dress and wander out to shut the thing off, (assuming you don't have a DSI unit with the switch inside) you will still have plenty of water in the HWT and it will cause no ill effects.

However, it is true that you should never light the thing with the tank empty.


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Polishnurse

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Posted: 06/07/12 07:11pm Link  |  Print  |  Notify Moderator

Water is drawn off the top of tank, so you should you run out of water, your hot water heater remains full. To drain or empty the tank you must remove the drain plug on the bottom.
What burns out is the heating element or the burner tube depending you your choice of fuels. Bill

old guy

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Posted: 06/07/12 07:13pm Link  |  Print  |  Notify Moderator

but to answer the question of a empty tank, you burn out the electric element and if the gas is going you will burn a hole in the bottom of the tank. Now this is only if the tank is void of water all together.

John Wayne

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Posted: 06/07/12 07:13pm Link  |  Print  |  Notify Moderator

It's just if you have an electric element in the water heater you don't want to turn it on if you don't have water in it. If you ran out of water there would still be some water in the water heater as it needs the cold in coming water to move the hot water out. So you couldn't pump it dry with the pump running.


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enblethen

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Posted: 06/07/12 07:16pm Link  |  Print  |  Notify Moderator

The pump will not pump water and should loose suction leaving water in the tank.
If operating on LP, a DSI unit has an ECO. The ECO will get hot and open and shut off. Some have a thermal fuse adjacent to the ECO and thermostat under some heat shrink.
An electric water heater if operated with no water will burn up the element. Some have a thermal cutout and may not destroy the element but don't bet on it.
Pilot light models will over heat with no water and can destroy the gas valve.
Any scenario could destroy the rig!


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mezerr

London Ontario

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Posted: 06/07/12 07:20pm Link  |  Print  |  Notify Moderator

Question answers! Thanks!!!!!!

jauguston

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Posted: 06/07/12 07:17pm Link  |  Print  |  Notify Moderator

Amazing! Mostly all right on correct answers. Good to see.

Jim


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beemerphile1

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Posted: 06/07/12 07:18pm Link  |  Print  |  Notify Moderator

You cannot run the water heater (WH) empty using the pump. The pump pushes water into the WH and water comes out. If water stops going in there will be no water come out and the WH will still be full.


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2oldman

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Posted: 06/07/12 07:39pm Link  |  Print  |  Notify Moderator

mezerr wrote:

what if i'm having a shower, and the fresh water tank goes empty, thus emptying the hot water tank, eventually.
That might be an awfully hot shower!

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