Friedrich 000 BTU'S, 9 service manual Compressor operation depends on t-stat settings

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

heat pump mode control features for heat pump with electric heat units

Reversing valve:

Always energized when “Heat” is selected on thermostat.

Compressor operation depends on t-stat settings:

If ambient indoor temperature is below the 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-energized for 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)When control is first energized or when power is restored after failure Note: Time delay is disabled during Test Mode.

Heat:

When there is a call for heat from the Wall thermostat the PCB will receive signals on terminal W, B, GL or GH. During compressor time delay, electric heat will turn on first. When com- pressor time delay is UP, the compressor will turn on.

Condition:

If outdoor coil temperature sensor drops to 30°F for less than 2 consecutive minutes, then unit will switch to electric heat. Thereafter, unit will switch back to Heat Pump heat if outdoor coil temperature sensor rises to 45°F or greater.

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.

Emergency Heat:

When compressor fails in heating season, allows user to disable Heat Pump. Heating with elec- tric heat only (See DIP switch position 7).

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