WIRING DIAGRAM NOTES
1. Model AC has no connection to its O/W2 or Y1/W2 outputs. Switch C does nothing. It can only control 1-stage cool and 1-stage heat.
2. Model HP or 2S, when used in air conditioner installations (Switch C ON), uses O/W2 to control second-stage heat. Refer to indoor unit
Installation Instructions for proper setup.
3. Model HP or 2S, when used in heat pump installations (Switch C OFF), uses O/W2 to control the reversing valve.
4. Special application: Model 2S thermostat with switch C OFF and switch D ON uses single-speed heat pump, FK4 fan coil with selected
2:1 size ratio heaters. Provides 3 stages of auxiliary heat for even heating comfort
via W/W1 and Y1/W2. Refer to FK4 Installation
Instructions.
5. Furnace second-stage is controlled by its internal algorithm. Refer to furnace instructions for proper setup.
6. Terminals marked with
*
may not be present on equipment.
7. Refer to fan coil Installation Instructions for proper wiring.
8. Select the
″
ZONE
″
position on the 2-speed heat pump control board.
9. Omit red and pink wires from diagram when wiring a 50ZP, ZH with 2-stage heaters.
10. Refer to outdoor equipment Installation Instructions for proper set up.
11. Program thermostat to bring on G (fan) with any W (heat) selection. See Step 4, Procedure 2, under set thermostat configuration.
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