Electric Water Heater Closed Loop System

[Tim Lauer]

In an industrial plant I want to use an electric water heater (208V, 3-phase, 4KW) to supply hot water in a closed loop piping system. Other words no faucets, hot water keeps circulating around and around to keep something from freezing. A guy in the plant says a electric water heater can not be used for this application. I've read NEC article 422 - Appliances and I don't see where it can't be used. Is there somewhere else I should be looking? This project is in MN btw.
Thanks,

 

[iwire]

As far as the NEC is concerned I would say 110.3(B) would be as close as you get.

However I have no doubt it is addressed directly in your local plumbing / mechanical code. Required expansion tanks etc.

 

[MEP_PM]

If there is a concern with using a potable water heater, you can buy an electric water heaters made for heating applications. http://lochinvar.com has several options in both categories.

 

[ActionDave]

In an industrial plant I want to use an electric water heater (208V, 3-phase, 4KW) to supply hot water in a closed loop piping system. Other words no faucets, hot water keeps circulating around and around to keep something from freezing. A guy in the plant says a electric water heater can not be used for this application. I've read NEC article 422 - Appliances and I don't see where it can't be used. Is there somewhere else I should be looking? This project is in MN btw.
Thanks,

You are using a water heater to heat water. There is no rule against that. I've seen water heaters used instead of boilers to heat rooms.

 

[iwire]

You are using a water heater to heat water. There is no rule against that.

I would not bet on it.

 

[ActionDave]

I would not bet on it.

So true.

 

[Netpog]

It's not just110.3(B) compliance, it's also a good idea. I spoke with the manufacturer of my on-demand water heater, and it was clear that only certain models are listed for closed loops. And that it would be unwise to violate the product's intended usage.

 

[ActionDave]

It's not just110.3(B) compliance, it's also a good idea. I spoke with the manufacturer of my on-demand water heater, and it was clear that only certain models are listed for closed loops. And that it would be unwise to violate the product's intended usage.

For an on demand heater I could see it, but for a regular storage tank water heater I can't see a reason not to do it other than some whacky, lawyer inspired bovine scatology.