Dual Element Water Heaters

[jerm]

We have natural gas for our cold water heater, but assuming I had one of these dual element electric water heaters, what would be wrong with rewiring the thing to kick both of them on at the same time, given I give it a properly sized breaker and wire? Wouldn't I get faster hot water then? Just thinkin. Ignoring listings, don't go there, too obvious. any other reason not to.

I really want one of those natural gas instant whole house tankless models. I'd put it on a APC 1500 UPS for power outages. (even with the natural gas models they need a little 120v for the igniter and electronics)

 

[iwire]

but assuming I had one of these dual element electric water heaters, what would be wrong with rewiring the thing to kick both of them on at the same time, given I give it a properly sized breaker and wire? Wouldn't I get faster hot water then?

Seen it done, well except for the proper conductor size.

A couple of brothers re-wired the water heater to run both elements at the same time. When the 30 amp cartridge fuses blew they wrapped them with Tin foil. The next thing that went was the internal components and wiring of the heater.

It was no coincidence we were there making electrical repairs after an electrical fire in another section of the home.

Just thinkin. Ignoring listings, don't go there, too obvious. any other reason not to.

The unknown.

Safety.

If you really want that best to buy a commercial unit designed for that, some commercial units I have installed have had 9 elements all capable of running at the same time.

We have natural gas for our cold water heater,

As far as this 'cold water / hot water heater thing.

I don't know about the rest of you but I have a hot water heater, I don't usually wait for the water to be cold before I heat it.

 

[LarryFine]

The next thing that went was the internal components and wiring of the heater.

That's correct. Every residential water heater I've wired used #12 internally. That wire will never carry 9KW (37.5a @ 240v) safely.

To run both elements, the best way would be to rewire the heater to have two independent circuits, and give it two separate feeds.

 

[dhducati]

while on the topic of water heaters, does anyone know of one that works on a 20a 12/2 240 circuit? They all seem to be 18 to 19 amps and with continuous load it needs a 30 amp breaker.

You can get water heater elements with different ratings. Using a couple of 3500W elements would allow a 20A 240V circuit (< 15A continuous).

 

[dhducati]

Sure. All the old water heaters were served with #12, since they weren't "quick recovery". You can still get one (with a full sized tank) that only needs a #12 feed but you have to go to a plumbing supply house. Obviously, the shorties often are lower wattage too.

My house has two 30gal shorties (because of limited space), which the plumber paralleled (water-wise, they have separate 30A circuits feeding them). Both came standard with two 4500W elements.

 

[Cow]

We have natural gas for our cold water heater, but assuming I had one of these dual element electric water heaters, what would be wrong with rewiring the thing to kick both of them on at the same time, given I give it a properly sized breaker and wire? Wouldn't I get faster hot water then? Just thinkin. Ignoring listings, don't go there, too obvious. any other reason not to.

One of our guys has done that before, it was a pain fishing the wires down the side of the tank. They had two 40-50 gallon WH in series running on 208 volt, but it still wasn't enough hot water. The customers were to cheap to buy a properly sized gas unit.:roll: So we decided to try running a second circuit to one of them. I'm sure it violated several listings/code articles but they were happy with the increased hot water capacity.

 

[Rampage_Rick]

Balderdash I say!

Hot water heater = NO
Cold water heater = NO
Instant water heater = :grin:

I'm especially partial to the ones with a remote keypad next to the shower. Punch in 108? and crank the shower dial to H. Why pay to heat the water to 120? and then mix in some cold? Yes I'm a shower fiend. I have a bathtub in my house that hasn't been used since I moved in 8 years ago.

We're actually working on an automatic drain/fill system for hottubs. 1 Instant water heater and 1 PLC for every 4 tubs. Person presses fill button next to tub, tub fills in 10-15 minutes, toss in a packaged pre-measured sanitizer (chlorine, etc) ready to go. Splish spash, tub's a bit low? Press fill again. Everyone's done, hit drain button. Tub drains automatically. System can also be operated remotely (Modicon M340 has a built-in webserver)