Honeywell Prestige 2.0 THX9421 Manual page 101

expires (whichever occurs first). Geothermal Radiant Heat
and Geothermal Forced Air Heat stay on when the Backup
Heat turns on.
EMERGENCY HEAT MODE
The thermostat turns on the Backup Heat to maintain the
desired temperature setting. Geothermal Radiant Heat
and Geothermal Forced Air Heat are not used.
Fossil Fuel Backup Heat (Backup Heat
NOT Allowed to Run with Heat Pump)
HEAT MODE
The thermostat turns on Backup Heat only when the
indoor temperature drops to the selected Backup Heat
Differential setting or the Backup Heat Upstage Timer
expires (whichever occurs first). Geothermal Forced Air
Heat turns off when the Backup Heat turns on.
Geothermal Radiant Heat stays on when the Backup Heat
turns on.
EM. HEAT MODE
The thermostat turns on the Backup Heat to maintain the
desired temperature setting. Geothermal Radiant Heat
and Geothermal Forced Air Heat are not used.
Set Up Geothermal Radiant Heat
1. Select Geothermal Radiant Heat as shown in Fig.
202.
Fig. 202.
2. Select the number of Radiant Heat Stages. See Fig.
203.
Fig. 203.
®
THX9321 PRESTIGE 2.0 AND THX9421 PRESTIGE
3. Select the universal terminals wired to the Geother-
mal Radiant Heat. See Fig. 204.
4. Select the Geothermal Radiant Heat Options. For
example: If this zone is Geothermal Radiant Heat
only – select None. See Fig. 205.
5. Select the Reversing Valve. See Fig. 206.
6. Select the number of Compressor and Backup Heat
Stages. See Fig. 207.
101
®
IAQ WITH EIM
Fig. 204.
Fig. 205.
Fig. 206.
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