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Old 10-05-16, 07:59 PM   #581
buffalobillpatrick
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Join Date: Mar 2014
Location: Florissant, Colorado
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Good concern Randen
I probably have twice as much pex per square foot as what u used (6" OC)
The state of Colorado rural counties inspector (Andy Clark) inspected it before insulation & Sheetrock.
He was impressed & said that it was "over radiated & probably wouldn't need over 140*F water to heat it" I think 170*F AWT will probably be needed at design temp.

It is getting down in the teens at night there now & it's doing fine.

The system is of my own design that I call "Buffer Centric"

There is a large Rheem ST120 DHW / buffer tank, it serves both functions.
The temperature of the tank is controlled by an ODR Tekmar 256, it ranges from 140* +- 15* when its above 60* outside, up to 170* +- 15* when its -20* outside.

In between the boiler & the tank is a GEA Flat 30 plate 5" x 12" heat exchanger.

When the Tekmar 256 tells the boiler to fire, 2 pumps come on, one on each side of the heat exchanger. Heat moves from the boiler into the tank.

During this the System pump (Grundfos Alpha) can be on or off depending on if any Ecobee3 thermostat is calling for heat.

Buffer tank mode:
If the system calls for heat after after the tank is up to the required temperature
& the boiler is off, heat will be pulled out of the tank and flow in the opposite direction through the heat exchanger to the system.

I had a system like this in my house for the last 3 years & now one is in my Sons new house.

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