[ILPlumber]

We have a small 120v WH at the shop sitting on a mezzanine above the offices. It has a vacuum relief valve as required by code.

Yesterday the city had an outage to change a fire hydrant. My little WH drained dry toasting the element. When they came back up to pressure I had a lot of air. It had been letting air in the whole time the pressure was down.

I had never really thought about this. So I thought I would through it out there. I spose I'll cut a soft seated swing check in the cold feed to prevent this from happening again.

 

[Plumberman]

Ought to do the trick

 

[MACPLUMB777]

Vacuum Relief Valve

YOUR PROBLEM IS YOU HAVE A SMALL TANK
THAT THE COLD WATER FEEDS FROM THE BOTTOM WHICH ALLOWS IT TO DRAIN,

SINCE THIS IS NOT A DAY TO DAY TYPE OF PROBLEM I WOULD JUST BE SURE THE POWER IS OFF AT THE BREAKER WHEN EVER THE CITY SHUTS OFF YOUR WATER AGAIN :thumbsup:

OR INSTALL A CHECK VALVE AT THE COLD WATER FEED AND THEN A SMALL EXPANSION
TANK TO PROTECT THE WATER HEATER :thumbup:

 

[Pipemaster]

Can a fatman get an amen on the expansion tank at the cold side and maybe a circuit breaker reset when the water comes back on the check valve

how about a viagra pez dispenser :thumbup: