Radiant floor from water heater

**wayne soper** · 06-16-2009, 01:57 PM

Interesting system, Water heater is heating the floor of the mud room and one rear second floor bedroom.
Everything looked Kosher to me but I haven't seen this application before for floor radiant.
Any thoughts and have any of you dealt with this before.

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Ted Menelly · 06-16-2009, 02:05 PM

I have seen it before but I never liked the idea. As I understand it the water obviously recirculates back into the water heater. What if they water lies stagnant in those lines for a very long period of time. Does bacteria grow in a closed system like that. I was always curios about what ramifications there might be. Probably none but just a thought.

Also, I don't thing I am seeing that entire vent at the angle the picture shows but if I am, what's up with that. Does it go anywhere. I guess the damper is on the tilted down end and the flue to the exterior is on the other side, or not. Just another curiosity.

**Rick Cantrell** · 06-16-2009, 05:03 PM

"As I understand it the water obviously recirculates back into the water heater."

Seeing as I am in middle Georgia and have never seen one (radiant heat) and most likely never will. I could be way off, but, I think that tank has a heat exchanger in it. Keeps the radiant heat water separate from the drinking water, or at least thats what I think.

**Jerry Peck** · 06-16-2009, 05:27 PM

There is a separate loop in the water heater which allows for the radiant system's heating water to NOT mix with the potable water.

When doing this, you are only allowed to do so with water heaters designed and intended for the purpose.

I see a lot of smoked up paint down by the burner access - from flame roll out?

**Billy Stephens** · 06-16-2009, 05:39 PM

Purpose of the Expansion Tank on the Hot Side ?
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**Jerry Peck** · 06-16-2009, 05:41 PM

Thermal expansion of the potable water.

What it is always installed for.

**Billy Stephens** · 06-16-2009, 05:46 PM

Originally Posted by Jerry Peck

Thermal expansion of the potable water.

What it is always installed for.

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Not if it's made by Watt's.
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Ron Bibler · 06-16-2009, 05:56 PM

This is what the flooring would look like under an Infrared camera.

Best

Ron

**Rick Cantrell** · 06-16-2009, 05:57 PM

"Not if it's made by Watt's."

Use only with potable water system. Do not operate in a
setting with freezing temperatures or where the temperature
can exceed 200°F and do not exceed the maximum working pressure specified for this Product in the Manual. Mount vertically only.

However that does bring up a question. Radiant heat, being a closed system, does need an expansion tank. But the water in the radient heat system is not Potable water.

**Billy Stephens** · 06-16-2009, 06:05 PM

Originally Posted by Billy Stephens

.
Not if it's made by Watt's.
.

Originally Posted by Rick Cantrell

"Not if it's made by Watt's."

Use only with potable water system. Do not operate in a
setting with freezing temperatures or where the temperature
can exceed 200°F and do not exceed the maximum working pressure specified for this Product in the Manual. Mount vertically only.

However that does bring up a question. Radiant heat, being a closed system, does need an expansion tank. But the water in the radient heat system is not Potable water.

.
Watts Shows expansion tank installed supply side as well.
File correct Watts Installation Instructions.
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**Jerry Peck** · 06-16-2009, 06:14 PM

Originally Posted by Billy Stephens

.
Not if it's made by Watt's.
.

Got it, I did not catch the "on the Hot Side" ... my mind was already at "on the potable water side" ... shame on me.

**Billy Stephens** · 06-16-2009, 06:32 PM

Originally Posted by Jerry Peck

Got it, I did not catch the "on the Hot Side" ... my mind was already at "on the potable water side" ... shame on me.

.
Mr Peck,

Maybe one of them Plumbing Guys can enlighten us as to the ins & outs of this added Equipment.

.
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**wayne soper** · 06-16-2009, 09:08 PM

Flue is good, Barometric damper stuck. No good. Closed system. backflow preventer installed. Expansion tank should be on the hot side for this as that's where the expansion is occurring. Domestic side of water heater does not require the expansion tank here( Ct) unless water pressure is too high and in most areas here it's not.
Still an odd ball.
Recommended installer service.
And, the house is heated with 2 furnaces. 13-15 yrs
Recommended conversion to hydro at time of furnace implosion
Thanks for the input

Ken Corwin · 06-17-2009, 06:49 AM

I have seen these systems. There is flat plate heat exchanger being utilized to protect the potable water from the hydronic system. On a call for heat one of the circulation pumps is energized passing water through the flat plate and heating the infloor tubing. There is an expansion tank and relief valve. These systems do work if sized correctly but they still are utilizing an inefficient appliance whether it's this oil fired water heater or a standard gas water heater, either way the appliance must be listed of use for both potable and hot water heating.

**Jim Robinson** · 06-17-2009, 01:39 PM

There are a number of this type around here. They are not necessarily lower efficiency. AO Smith makes a 96% efficiency dual use water heater, as do some others. The system can also work really well with a solar collector and storage tank.