Heating with domestic water 1

[carlosgw]

Is there a unit heater that can be used to heat using domestic hot water. Does the coil need to comply with ANSI/NSF61?
It would be to heat an apartment building stairway. The building does not have a heating hot water system but it does have a central domstic hot water system.
I can not use electric heat.
Any other ideas?

 

[TBP]

Check the plumbing codes in your jurisdiction. Many areas do not allow space heating and potable water to be part of the same system.

 

[ChrisConley]

What about a gas-fired unit heater? Or are you talking about a forceflow?

You could use the recirculation system as a source of heat for one unit heater (just extending the length of the system).

Any reason you can't use electric?

 

[PEDARRIN2]

The International Plumbing Code allows it.

You just have to have provisions to limit the hot water to the plumbing fixtures to a maximum 140 deg F and you must maintain the potability of the system, i.e. no chemicals and must not be a closed system.

 

[TBP]

It's been a while since I was involved with things like this, but I seem to recall at least some domestic water heater manufacturers specifically stating that their units were not designed for space heating applications, and that doing so would void the warranty.

 

[willard3]

It's a bad idea to use a domestic water heater to heat a building, don't do it.

 

[RossABQ]

I had never heard of this concept until a friend in Virginia (mild climate) told me his new house had it. The water heaters (I think it had two 70-gallon units) were specified for the duty. I believe it is a baseboard system.

 

[carlosgw]

You guys are all over the place.
All this is is running the hot water recirc. through a cabinet unit heater coil in the stairwell. The unit heater manufacturer certifies that their coil complies with NSF 61.
The problem I see is that I would not want to ever stop the flow (and stagnate the water) so the water would run through the coils in the summer also.
The point is moot as the city building code offciial here will not allow it.

 

[ChrisConley]

Our apologies for not answering your question correctly.

 

[willard3]

The code official has better judgement than you do.