Water Heater

Status
Not open for further replies.
R

RiponGuy

Member
Location
Wisconsin
Occupation
Maintenance
Boss wants a new water heater installed. I have 208v 3ph in the location he wants it. Am I stuck buying a more expensive industrial 208 3ph heater, or are there cheaper options. It needs to be at least 40 gallon, and the 3ph models are not cheap.
 
If you install a residential water heater in a commercial or industrial occupancy, you probably loose the warranty.
One of the issues would be the required recovery rate. A higher required recovery rate requires a higher input wattage or a larger water capacity.
If you choose to use a residential type, I believe you can get them with 208 volt elements so you still have the same wattage. If you use 240 volt elements on a 208 volt system, the wattage is only 75% of the nameplate. So the typical residential water heater with a 4500 watt element becomes a 3375 watt heater on 208 volts.
 
Last edited:
I agree with Don and want to add that their is also a possible listing issue if the water heater is listed for 240 and you install it at 208. Kind of silly as it will work fine but as Don stated 75% of the nameplate rating.

What size wire is available at the location? You may need a #10 at most
 
This is a new install. I just wanted to utilize to power source I had available at that location. I guess what I want to know is can I use the 3ph 208v that I have available on a single phase residential unit. There is about $1k difference in price from 1ph to 3 ph.
 
RiponGuy said:
This is a new install. I just wanted to utilize to power source I had available at that location. I guess what I want to know is can I use the 3ph 208v that I have available on a single phase residential unit. There is about $1k difference in price from 1ph to 3 ph.
Click to expand...
You need to determine what the demand will be for hot water. Why does he want a water heater?
Occasional hand washing you could get by with a 120v 5 gal unit, but they are almost the same price as a residential 40 gal electric.
 
ptonsparky said:
You need to determine what the demand will be for hot water. Why does he want a water heater?
Occasional hand washing you could get by with a 120v 5 gal unit, but they are almost the same price as a residential 40 gal electric.
Click to expand...
Didn’t think of asking for usage..
A commercial 10 gallon 208 is about $500
 
I just went through this. All the 1ph 208v water heaters were expensive commercial units. Ending up getting a 240v bradford white pretty cheap, with the intent of changing the elements. Interestingly the 240v water heater is rated for use at 208v (reduced wattage) so that covers the listing issue of using it at the lower voltage. Had to hang it in a crowded space above drop ceiling. That was not fun.
 
Heres a picture of the label on that water heater.
 

Attachments

  • 20201026_165840-1200.jpg
    20201026_165840-1200.jpg
    134.6 KB · Views: 19
@RiponGuy

Electrically your fine. Understand that the WH will have elements rated for 240 so a 208 you will get less output.

The only issue is some manufacturers will list their residential WH for residential use only. So there may be no warranty. But its done all the time
 
201026-1145 EDT

By operating at 208 instead of 240 you are short 600 W. Use a 208 to 240 autotransformer to boost the voltage. A 1 kVA will work. The autotransformer has to supply 18.8 A at 32 V.

.
 
RiponGuy said:
This is a new install. I just wanted to utilize to power source I had available at that location. I guess what I want to know is can I use the 3ph 208v that I have available on a single phase residential unit. There is about $1k difference in price from 1ph to 3 ph.
Click to expand...
Yes just use 2 phases of the three phase. This is done all the time. As has been said, if you are concerned about the lesser wattage, change the elements. As an alternative, usually the better 9 and 12 year units come with 5500 watt (@240) elements which would give you about 4200 @ 208. Done.
 
Status
Not open for further replies.
Top