Radiant return cold...

[Dylanlord381]

Our family recently moved into our home. We have a westinghouse combination hot water boiler. Radiant slab on the first floor, cast iron radiators on the second floor. The slab doesnt seem to be getting warm except along on edge, the water temp is set at 180 and the return lines feel less than room temp. On top of that when the first floor is calling for heat the hot water is also pumped 9nto the second floor zone. So I cant get the first floor above 64 and its 78 up stairs. Its 15f outside and I'm running space heaters to keep my wife from killing me bc it's too cold. I let the boiler run for 2 days straight when we moved in. It ran for about 3 weeks at 50-55 before we moved in and seemed ok. The slab is 34×32 with 3 1/2" loops but I dont know how long the loops are. What the hell is wrong with this system!?!

 

[peakbagger]

Is this a new house?. Who designed the system and was it installed to the design? Is this a slab on grade or is it lightweight concrete with a basement below?. What sort of insulation is under the slab and on the perimeter? What sort of floor finishes on top of the slab?

Are there any strainers or filters on the loops?. If the pumps are not matched to the required pressure drop of the tubing system you can put all the heat you want into the tubing and it will never make it to the end of the loop. The pump may have been matched originally but extra pressure drop in the system can cause the pump to run off its curve.