See Wiring Diagrams for more information.

Relays

This thermostat uses latching relays. When the thermostat loses power, the relays will remain in their last position until power is restored and all relays are reset to their correct position. Out of the box, the outputs may appear to be On when the thermostat is not powered. This is normal. Output states should only be checked when the thermostat is powered.

Temperature Offset After Power Cycle

To compensate for internal heat build−up from the electronics in the thermostat, the thermostat will add an offset to the actual temperature that it measures. If the thermostat power is cycled quickly, one can witness an immediate increase in the actual temperature displayed due to this added offset. The thermostat display will return to the actual room temperature after several minutes of operation.

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Carrier TP-NRH-A, TP-PRH-A installation instructions Relays, Temperature Offset After Power Cycle