Do I need to turn off hot water heater tank?

[Hiluxsurf]

Hi

I have a large gas water heater/tank - and need to do a very quick (5-10m) repair on a hot water line on the top floor of the house.

The water heater does not appear to have a shut off valve on the hot water out of the tank, only on the cold water into the tank.

If I turn off the cold water into the tank, and run a downstairs hot water faucet to reduce pressure
a) will that stop the hot water running totally upstairs? (or will there be enough residual pressure that it still flows)
b) will it cause any damage to the water heater? and/or do I need to turn off the burner?

(Obviously would rather avoid draining the tank if I can)

Thanks
C

 

[Reach4]

IMO, you don't need to turn off your gas water heater, but you could move the control to "vacation" if you have such a setting. That just maintains the pilot.

You will want to drain some water from a faucet lower than the pipes you are working on so the pipes you are working on empty out Open the faucet where you are working to admit air. And drain a couple gallons of water from the low faucet.

So a)yes it should, if your plumbing does not have a crossover.
b) no, but you might want to turn the temperature down or to vacation if you have that.

I am not a pro.

 

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[Fitter30]

Shut off valve on hot side is not normally piped just the cold.

 

[John Gayewski]

Shut the cold water side off so no cold water enters the heater. This will make it less likley to set the thermostat off. Then open a faucet on the lower level to relieve the pressure. Vacation mode for extended periods of time.

 

[Hiluxsurf]

Thanks all - no vacation setting but I can move to 'Pilot' mode - will that have the same effect?

 

[Reach4]

I don't think so, but am not sure. I am thinking that pilot mode may extinguish the pilot unless you are holding a button down the whole time. I would just turn the temperature down. If this work would extend a long time, I would try pilot, but be prepared to re-light the pilot.