R201

The R201 specification describes a microprocessor board for a combo air handler. It provides 2-speed line-voltage fan control, line-voltage water-pump control, 24 Vac control of an isolation valve, and a dry switching relay for a water heater. A flashing green LED means the microprocessor is operating; steady green means it failed; off means low voltage below 16 Vac, plus or minus 3 Vac. The sheet says the board must be factory installed inside the equipment.

Heating timing is a pump that energizes four times daily for 60 seconds, a 90 second blower-on delay, and a 20 second blower-off delay. Cooling uses high blower speed and a 45 second off delay. Optional inputs are freeze protection below 40 degrees, a heater booster that forces high speed, and a priority input. Line voltage is 120 Vac, 50/60 Hz. Fan outputs are 16 A resistive and the pump output is 5 A resistive. The sheet says the board is tested to UL 873. Size is 6.85 by 2.40 by 1.65 inches.