I have a 10-year old house. I have for heating zones for my Weil-Mclain Gold CGs boiler. Two upstairs, hot water heater and the last one is the in-floor heat in the basement. This zone has a digital Wirsbo thermostat. The basement zone isn't working. The temperature has been slowly dropping in the basement. I'll try to explain what's happening when I adjust the thermostat:

1. When I turn the temperature up on the thermostat, the icon on the thermostat display's the blinking fire icon which signifies a call for heat. In the boiler room, the Honeywell zone valve opens up, but the heat never comes on.

2. When I turn the thermostat down below the current temperature, the call for heat icon turns off and I can hear the zone valve closing.

The other zones seem to be working fine.

Any thoughts? Thanks.