Will a hot water heater reverse output?

[Chicago]

Have a 50 gal water heater in the basement. Wanted to make some plumbing adjustments prior to the water heater but there is no shut off valve besides the main inlet.

Main inlet > water heater > rest of house

If I cut the cold water pipe just before the water heater will hot water flow out? Or will gravity keep the hot water down?

I am able to drain the upstairs water as there is a sink in the basement if that would relieve water pressure from pushing down.

 

[LLigetfa]

If after relieving all the pressure, all taps are left closed, there is no opportunity for water to siphon out of the tank. If you want a little insurance, you could have a sharkbite cap at the ready.

 

[Sponsor]

 

[Sylvan]

Shut the main valve then drain the HW line and leave the faucet open (hot side)

Reason being if you shut the valve and someone decides to use a faucet you will get by pass through the faucet

Also while your working on the water heater installing a new shut off for example do not forget to install a 37" loop on the cold water to prevent stratification of hot going into the CW line

 

[Chicago]

Thanks! I’ll try it next weekend and let you know how it goes. Waiting for the fittings to arrive in the mail.