The circulation pump for my garage radiant floor heat stopped running. So my brother and I started trouble shooting. I thought that when I insulated my 1.5 and 1.25" copper pipes I might have cut the thermo wire. I had found some old wires and cut them to get them out of the way. Anyway, we put a signaling device on the wire from the Grundfoss circ. pump and the signal went right to the control panel. So, I remembered that I had not changed the battery in the thermostat since I put it in, probably two years ago. Changed the batteries. Circ. pump still not on. ? We then went to control panel in boiler room. And he thought that maybe the relay that closes the circuit for the 120(115) electricity to the pump was bad. We swapped that out with one that was not being used. Little green light above that relay comes on, was not on before. Circ. pump now runs.? So then we switched the relay back to be sure it was the relay. Little green light above the relay still on. Circ. pump still runs.? Could the batteries being so old, maybe totally dead, have caused this?