Auto fan problem

[mikevalentine]

Hi EWC,

I had a Ultra-Zone model EWC-ST-2C installed with four zones running. I assume after reading your site, two have dampers and the others are the masters ???

Anyway, four Honeywell Chronotherm 3 Thermostats are installed. Heat and air work fine but the fan will not auto. Fan works as designed when in the "fan on" mode. All zones are acting the same way.

If one thermostat is bad will it screw up the whole system. Any help appreciated

Mike Valentine
401 667 7202

[Eric K.]

Mike,

The ST series of control panels is Master/Slave, meaning Zone 1 is the Master or controlling thermostat and it determines what mode to allow the system to operate in. Also, Zone 1 is the only thermostat capable of controlling Fan only operation.

The remaining zones are slaves and are only capable of demanding heat or cool if the master thermostat is in the appropriate mode. Also, the slave thermostats are not capable of demanding fan only operation.

I hope this helps, feel free to contact me if you have further questions.

Eric

[mikevalentine]

Eric,

Thanks for you response!!

So am I to assume that if the thermostat is wired with 6 wires rather than 3 it is the master??

I have one master zone where the fan will not shut off in the auto or fan mode whatever temp is set.

I have two zones that the fan mode works but not the auto mode when calling for heat.

Is this an indication of a bad controller??

[Eric K.]

Mike,

6 wires would indicate it is the Master Thermostat.

Please contact me at the number below when you are home to trouble shoot your system in greater detail.

Eric