Buffer tank necessary?

Kevin O. Pulver

It's about 1500 square feet in a basement with ICF walls and 2" of ridgid foam underslab. Very little heat loss. I am just hooking it up for them. I have never used a water furnace/geothermal for a heat source. They said it would provide 120 water which is plenty for in slab, but I haven't determined how many GPM it will do at that temp. That temp sounds optimistic from what I've heard of them.
I posted earlier about using a hot water heater to bump up the temp if necessary and to act as a buffer tank. The burning question is, in your experience will I need the buffertank/backup heat with the geo? Sorry I don't have the exact numbers for you. Thanks in advance.Kevin

Craig Bergman

With Geo

we always use a buffer tank. We have never hooked up the electric elliments yet. If it's 4 ton or smaller we use a 30 gallon. For a 5 or 6 ton we use a 50 gallon and we pipe it as follows...

Remove the bottom elliment and pipe that INTO the Geo with the proper cicrulator. The Geo OUT goes into the center "pop-off" hole with a 30lb pop-off. the Hot out tap goes to the radiant system with the proper circulator. Remove the dip tube, cut off about a third and drill extra holes in it for the radiant return.

When piped this way the Geo unit can be set up to keep the buffer tank at design temp, no higher than 120*, and the radiant will draw whatever the buffer will give it.

I doubt 120* water would be your set point far an ICF basement slab....Maybe around 105*?? (Just a guess)

Bergy

Craig Bergman

With Geo

we always use a buffer tank. We have never hooked up the electric elements yet. If it's 4 ton or smaller we use a 30 gallon. For a 5 or 6 ton we use a 50 gallon and we pipe it as follows...

Remove the bottom element and pipe that INTO the Geo with the proper cicrulator. The Geo OUT goes into the center "pop-off" hole with a 30lb pop-off. the Hot OUT tap goes to the radiant system with the proper circulator. Remove the dip tube, cut off about a third and drill extra holes in it for the radiant return.

When piped this way the Geo unit can be set up to keep the buffer tank at design temp, no higher than 120*, and the radiant will draw whatever the buffer will give it.

I doubt 120* water would be your set point far an ICF basement slab....Maybe around 105*?? (Just a guess)

Bergy

Kevin O. Pulver

Thanks Bergy

Yes, 120 is too hot I'm sure. That's what the max supply apability is supposed to be, but I wouldn't want to bet on it. I appreciate your help. Kevin