Aprilaire Model 8570 installation instructions The B terminal will energize when in the Heat mode

6. CHECK HEATING OPERATION

Notes:

1.To avoid the minimum off times during system checkout, always start and end the check out procedure in the OFF mode.

2.Do not operate heat pumps in the heating mode at high outdoor temperatures for extended periods of time.

•Set the thermostat to the OFF mode.

•Set the thermostat to the HEAT mode:

–The B terminal will energize when in the Heat mode.

•Raise the heat setting to 5° higher than the room temperature to initiate a 1st stage heat call. The mode display will change from "HEAT MODE" to "HEATING", which will flash when the thermostat is calling for heat:

–Furnace, Boiler: W1 (and G if GAS/ELEC dip switch is set in the ELEC position) terminals will energize.

–Heat pumps: Y1 and G terminals will energize.

•Wait for 2nd Stage:

–Furnace, Boiler: Minimum-on time for 1st stage is 2 minutes.

•W1, W2 (and G if GAS/ELEC dip switch set to the ELEC position) will energize.

–Heat pumps: Minimum-on time for 1st stage is 4 minutes.

•Y1, W1 and G terminals will energize if SINGLE/MULTI dip switch set to SINGLE and ELEC/GAS dip switch set to ELEC.

•Y1, Y2 and G terminals will energize if SINGLE/MULTI dip switch set to MULTI.

•W1 will energize if SINGLE/MULTI set to SINGLE and ELEC/GAS set to GAS.

•Wait 4 minutes for 3rd Stage (multi-stage compressor heat pump systems only):

–Y1, Y2, W1 and G terminals will energize if SINGLE/MULTI set to MULTI and ELEC/GAS set to ELEC.

–W1 will energize if SINGLE/MULTI set to MULTI and ELEC/GAS set to GAS.

•Set the thermostat to the OFF mode.

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