23 PB
OPERATION
Sequence of Operation
Low speed selection from Indoor Controller (Factory default)
High speed selectioon from indoor motor controller (Field wiring Option)
Defrost Mode Termination
Once a defrost mode has been initiated, it shall be terminated immediately and reset the internal timing if the coil sensor
temperature exceeds the selected termination temperature. If the temperature select shunt is not installed, the default termination
temperature shall be 50°F. The Low Pressure Switch is ignored for 90 seconds following termination of a Defrost. Once a defrost
mode has been initiated, an internal timer shall count the time that the defrost mode is engaged and compressor is energized. After
14 minutes of operation in the defrost mode, the defrost sequence shall terminate immediately and reset internal timing regardless
of the state of the coil sensor temperature. If a defrost cycle is terminated by time and the coil temperature did not remain above
XX°F for X minutes, the controller will return to an un-calibrated state.
Blower Control
All Vert-I-Paks, by default, will be congured to low speed blower operation. The speed setting can be changed to high speed by
updating the speed tap settings on the fan control relay. Any non-Friedrich thermostat or low voltage device being powered by the
Vert-I-Pak will need to be reviewed and approved for use.
NOTE: The fan speed setting cannot be changed at the thermostat. Regardless of wiring GH and/or GL, the unit will continue to
operate at the speed setting at the fan control relay. TO change fan speed from low to high change the speed relay tap from red to
blue wire.
Figure 503 (Blower Speed Control)
Forced Defrost
When the “TEST” terminals are shorted with the “Y” and “B” inputs active, the ASCD timer will be canceled and control will enter the
defrost mode. If the short on the “TEST” terminals is removed and then reapplied, the defrost mode will be exited and the control will return
to heating operation. These modes can continue to be cycled through by removing and reapplying the short to the “TEST” terminals. The
Compressor Delay Time (30 Seconds) will remain active when switching between defrost mode and heat mode with the test feature.
The Enable Temperature is ignored when the “TEST” terminals are shorted, and a forced defrost can be entered with the coil temperature
above the Enable Temperature (35˚F). The forced defrost will terminate when either the coil temperature exceeds the selected Termination
Temperature, 14 minutes of defrost has accumulated, or the test terminals are shorted a second time.
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