I have an air handler and water-to-air exchanger. There are no heat strips or condenser, not a heat pump, just the sheet metal box and fan. And of course 24VAC transformer and relay... I have the 24VAC going to a thermostat to power it and one lead to the relay, currently connected to "Aux".
TH3210D:
C 24 Vac common
B Changeover valve energized in heating
R 24 Vac power
L Sends output when set to Em. Heat
O Changeover valve energized in cooling
G Fan relay
Y Compressor contactor
Aux Auxiliary heat relay
E Emergency heat relay
This probably isn't the best thermostat for this application, it's just a spare one my dad had and I borrowed.
http://s3.supplyhouse.com/product_files/Pro3000Install1.pdf I believe that it's meant only for a HP and does not directly control the fan itself. Connecting to the (G) Fan relay terminal does not result in the relay tripping, unless I manually slide the "Fan" switch from auto to on. I of course want the fan to come on when the tstat calls for heat. Suggestions? I've checked the rest of the terminals and unless I was just impatient, am not seeing 24V on any when the tstat is showing "Heat On".
Connected to Aux, it does automatically kick the fan on, when the tstat shows the temp a couple or more degrees below the set point and "Aux Heat On" displays. Works, maybe good as I'm going to get out of this tstat...
Thanks.
PS. P&M 2840 feeding into my basement as only heat source for that part of the house. Heat pump upstairs, toasty warm upstairs without HP having been on in last few days. Basement is nice and warm, heat rises, whole house is nice and warm. Single digits tonight, got it loaded up with white/red Oak.