Wiring water heater to run both heating elements simultaneously

[dpilot83]

I have been looking for 30 to 50 gal electric water heaters I could purchase that would allow me to run both heating elements simultaneously. I have also been looking for electric water heaters that I can order with higher wattage heating elements than what appears to be the standard of 4,500 watts.

It appears they can be ordered from some MFG's but no one that I've been able to find carries them or is even willing to order them from the mfg.

Does anyone know where I can order them like that? If not, could I just buy non-simultaneous water heaters and wire them for simultaneous operation myself?

To prevent the top thermostat from being overloaded by the current of simultaneous operation I would:

- Remove the wiring between the top thermostat and the bottom thermostat
- Add a second totally separate 30 amp circuit to feed the second thermostat

If I could do this I wouldn't mind running two water heaters that are maybe 40 or 50 gal water heaters to meet my needs. But if I can't do something like this I feel I would need at least three 30 gal water heaters and possibly even a fourth 30 gal water heater to get the capacity I'd like to have for our large family and 3+ simultaneous showers or baths.

While I'm talking about multiple water heaters, what's the consensus on water heaters being plumbed in series vs having them plumbed in parallel? In a way I feel like being plumbed in series would be beneficial because if only one person takes a shower/bath, it's likely that only the first water heater in the series would end up turning on.

On the other hand, I wonder if I plumbed them in parallel, perhaps it would be more likely to have all four of the heating elements contributing to warming water sooner during times that lots of hot water is needed?

 

[WorthFlorida]

You're looking for a commercial grade WH like Lochinvar water heaters. Expensive and usually only sold to licensed plumbers or contractor.

For standard water heaters, 240v you can buy 5500 elements without issues at Home Depot or Amazon.

A better way is use a thermostatic mixing valve like one made by CashAcme, Tank Booster™ PRO Thermostatic Mixing Valve. I've installed a few and they work great.

You set the WH temperature to 140 degrees and the mixing valve brings the temperature down to a safe 120 degrees. The WH is then equivalent to a 86-90 gallon unit.

 

[Sponsor]

 

[Sedin26]

If you look through the Bradford White site you’ll see that quite a few of the residential electric water heaters can be ordered with big elements and pre-wired for simultaneous operation. You can also set it up yourself, as you mentioned, though it’s nice to have it ready to go from the factory. The manuals detail how it’s done if you get a standard one and want to change the operation mode.

You’ll never get this at a box store but I’ve found that a couple of the local plumbing distributors will sell to the public. I’m not a plumber so I head in at a quieter time and they’re happy to order whatever I want.

 

[Fitter30]

5k element is 21 amps @240vac. Thermostat and limit rated @ 30 amps. Could wire a 60 amp contactor limit controlled to feed power to both elements or two 30 amp. By making wiring changes any rating will voided and the warranty. Gettin
Piping two heaters reverse return /first in last out.

If you look through the Bradford White site you’ll see that quite a few of the residential electric water heaters can be ordered with big elements and pre-wired for simultaneous operation. You can also set it up yourself, as you mentioned, though it’s nice to have it ready to go from the factory. The manuals detail how it’s done if you get a standard one and want to change the operation mode.

You’ll never get this at a box store but I’ve found that a couple of the local plumbing distributors will sell to the public. I’m not a plumber so I head in at a quieter time and they’re happy to order whatever I want.

 

[Sedin26]

5k element is 21 amps @240vac. Thermostat and limit rated @ 30 amps. Could wire a 60 amp contactor limit controlled to feed power to both elements or two 30 amp. By making wiring changes any rating will voided and the warranty. Gettin
Piping two heaters reverse return /first in last out.

Why not just order the water heater in the specific configuration that’s needed? Supply two 30 amp circuits and the appropriate wiring and it’s good to go. Perhaps add a thermostatic mixing valve as well for additional headroom.

I’m not sure why changing a standard heater to simultaneous operation would void the warranty, as the manual specifically states that it is rated to operate in both ways and explains how to wire it for your particular instance, as needed.

Simultaneous operation seems to be done so rarely, and I guess I understand why, but it works very well if done with a supported water heater and set up properly.

 

[Fitter30]

Just because a manufacturer would build a two element separate power doesn't mean you can modify something like that the manufacturer would do. Any certifications and warranty. would be lost. Your first post stated just put power to the lower thermostat. Nothing about a safety high limit that's why my post 4 adds that protection.

 

[Sedin26]

Just because a manufacturer would build a two element separate power doesn't mean you can modify something like that the manufacturer would do. Any certifications and warranty. would be lost. Your first post stated just put power to the lower thermostat. Nothing about a safety high limit that's why my post 4 adds that protection.

Not sure if I can put a link here or not - I'll try it - https://s3.amazonaws.com/bradfordwh..._upright_m2_archived_servicemanual_47104a.pdf

It's feasible I am mis-reading something but I've seen it done the way I'm describing (by plumbers) and it seems to be one of the options they describe here.

 

[Jeff H Young]

Not sure if I can put a link here or not - I'll try it - https://s3.amazonaws.com/bradfordwh..._upright_m2_archived_servicemanual_47104a.pdf

It's feasible I am mis-reading something but I've seen it done the way I'm describing (by plumbers) and it seems to be one of the options they describe here.

Good Points it might sound crazy in the USA and common in other countries to wire that way . nothing wrong with contacting B/W or your building and safety department

 

[Sedin26]

Good Points it might sound crazy in the USA and common in other countries to wire that way . nothing wrong with contacting B/W or your building and safety department

That brings up a good point. I know that some jurisdictions (power companies) require notice before setting up water heaters this way (due to the higher power usage). Probably most don’t but it’s a consideration.
If I were doing it I’d get a permit.

 

[Jeff H Young]

That brings up a good point. I know that some jurisdictions (power companies) require notice before setting up water heaters this way (due to the higher power usage). Probably most don’t but it’s a consideration.
If I were doing it I’d get a permit.

Im talking safety and codes things like plumbing codes or electrical codes arent worldwide one code for everyone

 

[Fitter30]

Not sure if I can put a link here or not - I'll try it - https://s3.amazonaws.com/bradfordwh..._upright_m2_archived_servicemanual_47104a.pdf

It's feasible I am mis-reading something but I've seen it done the way I'm describing (by plumbers) and it seems to be one of the options they describe here.

Not sure if I can put a link here or not - I'll try it - https://s3.amazonaws.com/bradfordwh..._upright_m2_archived_servicemanual_47104a.pdf

It's feasible I am mis-reading something but I've seen it done the way I'm describing (by plumbers) and it seems to be one of the options they describe here.

Using two top thermostats for each element.