I have a White-Rogers model 1F80-51 digital thermostat. It controls my
forced air furnace and my a/c. I recently installed a whole house, year
round humidifier (the Neptronic SKR-40). This humidifier turns on the
furnace fan when there is a call for increased humidity. In other
words, the humidifier will operate year round and simply turn the fan
on when the humidity drops below the set-point.
The humidifier dry contact relay was wired to the furnace across the G
and R 24V connections.
When the humidifier turns on the furnace fan, the ac unit is also
turned on. I've traced this down to the fact that the White-Rogers
thermostat is shorting it's cooling system control (the Y terminal) if
the thermostat fan control is set to 'AUTO' and the humidifier turns on
the fan. I've demonstrated the Y contact is being turned on by the
thermostat by disconnecting the wire to the thermostat and seeing that
the wire remains at 24V while the thermostat Y pin is taken to 0V. I've
temporarily worked around this problem by simply dropping power to the
a/c unit. Clearly this won't work when it gets warmer outside!
My question is, is there a way to wire up the White-Rogers thermostat
so it doesn't turn on the a/c when the humidifier forces the furnace
fan to turn on? Or do I just need to buy another thermostat?
Thanks for any help.