vpak electronic control board and wall thermostat sequence of operation (Continued)

cool mode control features for cool with electric heat units

Reversing valve:

Always de-energizedwhen “Cool” switch is selected on thermostat.

Compressor operation:

If ambient indoor temperature is above set point temperature depending on t-stat differential and the compressor is not time delayed, turn on compressor. If ambient indoor temperature is below set point depending on t-stat differential, turn off the compressor.

Compressor time delay:

The time delay feature is de-energizedfor a period of time that varies randomly from 180 to

240 seconds. Compressor time delay is initiated every time the compressor is “off” due to:

(1)Satisfying the temperature set point,

(2)Changing mode to fan only

(3 )Turning the unit off.

(4)Control is first energized or when power is restored after failure Note: Time delay is disabled during Test Mode.

Indoor coil frost protection (Error Code 07):

While in cool mode: If the indoor coil frost protection sensor reads 30°F for 2 minutes continu- ously, turn off the compressor, but continue fan operation. While the compressor is out and the fan is running: when the indoor coil frost protection sensor reaches 45°F, turn on the compres- sor. However, the compressor must still wait a standard time of 180 to 240 seconds. While 07 flash, heat operation is disabled.

Fan delay:

This is only for fan ‘cycle’ mode and not for fan ‘continuous’ mode. When unit cycles cool- ing ON – start the fan 5 seconds EARLY. When unit cycles cooling OFF – DELAY the fan off for 30 seconds. Note: the fan delay is disabled during Test Mode.

electric heat mode control features for cool with electric heat units

Reversing valve: Always de-energized when “Heat” button is pushed.

Compressor operation: Compressor does not operate in this mode.

Electric heat operation: If temp is below set point, depending on t-stat differential, turn on electric heat. If Ambient is above set point depending on t-stat differential, turn off the electric

heat.

Fan delay: This is only for fan ‘cycle’ mode and not for fan ‘continuous’ mode. When unit cycles heating ON – start the fan 5 seconds EARLY. When unit cycles heating OFF – DELAY the fan off for 15 seconds. Note: the fan delay is disabled during Test Mode.

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Friedrich 9, 000 BTU'S service manual Cool mode control features for cool with electric heat units