Water – energizing both elements of electric hot water heater

hot-watersolarwater-heater

I'm considering using an electric hot water heater (EHWH) with upper and lower heating elements as an electric diversion load. This EHWH would be for pre-heating the water bound for the standard HWH.

Often the total watt rating of the EHWH is larger of the two elements – instead of the sum. Is it allowed (*) to energize both heating elements at the same time?

  • 'allowed' means – general technical limitation of the EHWH – not necessary code related. Also I'm also interested relevant code limitations and their reasons.

** Might also be relevant to post in a different forum?

Best Answer

Although different heater manufacturers have and could still do different things, they rarely would configure the heaters to operate both elements at the same time because amperage draw doubles, wire gauge size increases, fuse size increases and little is gained in heat recovery.

Pic below illustrates operation of elements on standard dual-element heaters with non-simultaneous operation.

enter image description here Pic courtesy of A.O. Smith Co.

Is it allowed (*) to energize both heating elements at the same time?

NO, unless the heater was originally designed for that. You can never modify equipment (especially a boiler) without manufacturer's permission.

Related Topic