I have radiant heat with the water lines in the concrete of my garage. I replaced the original thermostat which had a only 2 terminals with a red and white wire coming from my wall with an old digital thermostat that had 4 hookups in back. I connected the red and white wires to the red and white terminals on the digital thermostat. Now it won't quit running for the garage heat.

I have a three zone system where it heats either the garage, the basement, or the bathroom floor. There are 3 separate switches that directs the hot water where it needs it.

I changed it back to the original and it still wouldn't quit running. I even took the thermostat off completely, and the pump is still pumping. I eventually had to disconnect the electricity from the pump to make it quit pumping.

I did not disconnect the electricity before changing the thermostat.

Any ideas?

Never mind, I figured it out. The electric valve was only closed a quarter of the way, so when the pump cycled, it ran water through the valve. When I stitched the thermostat, it must have kicked on for a split second and caused the valve to open partway. I was able to manually close it with a screwdriver and it works fine now.