User Guide

SEQUENCE OF OPERATION

Assuming the default ON/OFF delays have not been changed and the user interface (UI) is receiving 24 VAC on the RED and BLUE

thermostat wires, the following will occur:

1. When the UI receives a thermostat input, the (UI Input Indicator) will change from ON to CONTINUOUS BLINKING.

2. The (Motor Indicator) will change from OFF to SOLID ON, and the motor will turn on. The motor will operate at the default airﬂow

setting or the last value selected in this demand.

3. When the thermostat demand ends, the (UI Input Indicator) will change from CONTINUOUS BLINKING to SOLID ON. If the UI

was receiving a (Y1 or Y2) demand, the motor will turn off and the (Motor Indicator) will change from SOLID ON to OFF. If the

UI was receiving a (W1 or W2) demand, the motor will continue to run for 90 seconds, then the motor will turn off and the (Motor

Indicator) will change from SOLID ON to OFF.

NOTE: If the thermostat is set to FAN ON and UI is receiving a thermostat input on (G), the (UI Input Indicator) will display as

CONTINUOUS BLINKING, the (Motor Indicator) will display as SOLID ON, and the motor will operate at the (G) airﬂow value.

The motor will follow the sequence above including delays; however, it will return to the (G) airﬂow value when all other demands

are de-energized.

The UI is set by default to automatically switch from W1 to W2 airﬂow 10 minutes after the thermostat demands for W1 is received.

This delay setting is to accommodate two stage fossil fuel systems with single stage thermostats.

If the UI is receiving a 1st stage (W1) thermostat demand, it will transition to the 2nd stage (W2) airﬂow value if one of the following occurs:

– The UI receives the 2nd stage thermostat demand

– The UI receives the 2nd stage input on the 16-pin plug

– The UI (W1 to W2) time delay times out