Do I need to rethink?

All the discussion about Mass Heat's system has me concerned with my install. Have most of the parts and was going to dig the trench. Butttttt! Real quick, heat loss calc via online calculator comes to approx 40-45kbtu for infloor basement and WAHX, DHW will add but EWD factored for it. Would ask him, but he isn't using the site any longer and hasn't answered email. EKO 40, 850 gallons pressurized storage in pole barn, with 60 gallon buffer tank in house. 260 foot roundtrip to barn. Figured 70kbtu total load with DWH so 7gpm for flow at a delta of 20. Warmest water sent back to storage would be 140 degrees due to buffer reusing water over and over down to 140. Was going to use Rehau 1 1/4 just to make sure, but after reading an old thread about how we always seem to overkill I decided on the 1" that EWD said is all I needed. So if my Delta is at least 40 degrees, and I use 1" Rehau (Thermopex), and have 7 gpm I should be good. Right?

Brandon

what will you be using for a pump?

Have 15-58FC's on infloor and several extra's, so thats what I was gonna use. Thought they would easily move enough water.

Brandon

Siegenthaler's Hydronic Simulator software says using 260 ft. of 1" PEX alone with a Grundfos15-58 on speed 3 will flow 6.53 GPM.

DaveBP, what happens to that calc if Armaton goes with 1 1/4" PEX?

6 and a half gallons is not much....... only if you can maintain that 40 degree delta. Bigger pipe and a smaller circulator or the circ turned on 1 or 2 instead of 3.

TS