Swap out the " bad " thermostat with the tstat that is working ?Hello, I am having a problem with the main floor thermostat. The heating system was a oil to gas conversion and the original line vlotage wires are now used as a conduit for low voltage. The 2nd floor thermostat is working properly but the main floor is not firing the boiler. The system is a 3 zone basebaord heat with 3 thermostats. The thermostat that is not working fine is flashing stg2. Unsure if the wiring is different and thats why its showing this. The hook up is standard thermostat wire hooked up to the line wire. I have the wires hooked up to RH and W1 on both thermostats. I am unfamiliar with this thermostat and could use some help before I go into relay switches and zone valves. Thanks
Ohm out the tstat wiring . Is the wiring unbroken from start to finish or does it have splices / joints ?
Are there zone valves , or does the whole house start heating when the boiler fires up ?
Can you run new tstat cable for the tstat that is not working ?