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+-- Thread: On demand water heater for in floor radiant heat? (/showthread.php?tid=7367436)
On demand water heater for in floor radiant heat? - goaliedad - 01-30-2022
I have our house ready to add a heat source for in floor radiant heat. There is an on demand water heater available for $400
Will it work??
RE: On demand water heater for in floor radiant heat? - EightFingers - 01-30-2022
Better spring for something more around $1000 or so. Also keep in mind those need yearly maintenance.
Usually involves taking it offline and pumping vinegar through it to clean out calcium deposits in the heat exchanger. Get the “optional” hose connector kit for the maintenance.
RE: On demand water heater for in floor radiant heat? - aquaticjim - 01-30-2022
(01-30-2022, 06:38 PM)goaliedad Wrote: I have our house ready to add a heat source for in floor radiant heat. There is an on demand water heater available for $400There is a reason the radiant heating boilers are more expensive. With a once through On-Demand water heater, the incoming water temperature is pretty low and constant. With a closed loop system, you have variable pressures and temperatures to deal with. Also, with a closed loop, you treat the water in the loops so it will not corrode or scale.
Will it work??
RE: On demand water heater for in floor radiant heat? - JosephP - 01-30-2022
(01-30-2022, 08:20 PM)EightFingers Wrote: Better spring for something more around $1000 or so. Also keep in mind those need yearly maintenance.
Usually involves taking it offline and pumping vinegar through it to clean out calcium deposits in the heat exchanger. Get the “optional” hose connector kit for the maintenance.
Price is irrelevant...BTUs matter. Not completely irrelevant, but sounds like he is buying it on Facebook. So maybe it is a $1000 unit...
PS: make sure you can hook it up. I looked at tankless, and would have needed to upgrade our gas line and figure out how to vent it. That would have cost significantly more than the heater.
RE: On demand water heater for in floor radiant heat? - blackhat - 01-31-2022
The cynic in me always asks why so cheap. What’s wrong with it? Does it require a special venting material? Is it certified for use as a space heating appliance? Is it close to matching the BTU load from the floor? God forbid you want to get hot water from it as well.
Can a tankless water heater be used to heat a floor? Sometimes maybe.
RE: On demand water heater for in floor radiant heat? - goaliedad - 01-31-2022
Thanks for the input. It is An LP unit 199k btu from what I can tell. The guy says he upgraded because it is LP only and natural gas was run in his area
RE: On demand water heater for in floor radiant heat? - jteneyck - 02-01-2022
(01-31-2022, 07:43 AM)goaliedad Wrote: Thanks for the input. It is An LP unit 199k btu from what I can tell. The guy says he upgraded because it is LP only and natural gas was run in his area
I think a key issue is whether the unit is the modulating type or just runs flat out all the time. You need pretty low temperature for underfloor heat, like 130F. If the heater can run that low, great. If not, you will need some sort of tempering valve arrangement and maybe a holding tank.
John
RE: On demand water heater for in floor radiant heat? - EightFingers - 02-01-2022
Mine puts out 120 deg continuous.