no temperature difference

Mr. Breeze

Just fired a radiant system; stapled up with transfer plates
Source is a electric water tank; 9 gang manifold, 7 loops 300', 2 about 140'; 1/2" PEX. R-foil under about 1/2 of system, the balance exposed to heated, unfinished basement. System is heating floor but I have no temperatue drop from supply to return. 115 to 120 degrees in / 113 to 118 back out. ????? Installed a 26-64 Grundfos pump in place of 15-42 because I knew I was at the max for the 15-42. No difference. I have 2, 6000 watt elements wired simultaneously on 40 gallon tank. Again, I am on the edge with the heat loss of my living space so I need to make sure I am getting all the heat out of this tank I can before looking into addition BTU's. Any tips or advice appreciated. floor surface is 50% carpet, 50% tile. I have valves on each loop and have tried restricting flow with no luck.

frank s

Did you

Did you leave an air space between the insulation and the tube/plates, if not there's your first problem, and or drop the water temp

Mike T., Swampeast MO

System heating floor...

Sounds OK.

Transfer plates? "flashing type" or extrusions?

What is the floor surface temperature?

What was the outside temperature at the time?

Is the floor surface temperature what you planned for?

If the floor temp is what you planned and the outside temperature is well above design the radiative heat loss is controlling the delta-t. Just as it should be.

Dan Peel

Tank rating

I do hope this is a home build and not a job you charged people for. I'm going to guess the rating plate on the water heater says "upper element 3000w, lower element 3000w, max. 3000w". Twinning the elements is a disaster waiting. Higher inlet temps and lower flow rates will give you higher Dt. Dan

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