I noticed that my thermostat works fine and opens the zone valve for the basement. The problem is that it won't send a signal to the furnace to turn on and heat the water.

I have no problem with the upstairs zone valve. It opens and turns on the furnace.

Is this a wiring issue?

Thanks
Paul

Could be a zone valve issue. Many zone valves have a switch to turn the boiler on. Since you did not provide a Brand or exact model of the zone valve I can be of no further assistance in this issue since all else will be guesswork with out the proper information.

It's a Honeywell Zone Valve V8043E1012. I already changed the motor on the valve and it opens up. The problem is that the valve does not send a signal to the furnace to turn on. I have the same valve next to it connected to the upstairs heat and that one works fine.

There is a switch in that valve also since it uses 4 wires. Two of the wires power it up and open the valve on a signal from the thermostat. The other two wires go to a switch inside the valve that tell the boiler to turn on once the valve is open. It could be the switch in the valve is defective not allowing the boiler to come on. See below.

See figure 14 page 14.

http://customer.honeywell.com/techlit/pdf/60-0000s/60-2133.pdf

Thanks for the info. I will take another look at the red wiring that connects to the circulator on the furnace. I already check the yellow wiring and its fine. I will check the switch inside the valve to see if that clears up the problem.