Setting Up A Regular Or Timed Defrost Off-Cycle; Control Behavior When Manually Starting Or Stopping A Defrost Off-Cycle - Penn A421 Series Installation Manual

value for the code.
With the current parameter value displayed, press Down or Up to scroll through all of the
4.
parameter code's usable values and display the preferred value.
With the preferred parameter value displayed, press MENU to save the displayed value and go
5.
to the next parameter code.

Setting up a regular or timed Defrost Off-Cycle

The controller enforces the following behavior:
• At power up, the initial Defrost Interval (dI) does not have a Defrost Cycle (dFt).
• Subsequent defrost intervals (dI) begin with the selected dFt value.
• All defrost intervals have the same length.
To set up a regular or timed defrost cycle:
1. Select a dI value between 2 hours and 24 hours.
Note: A dI value of 0 indicates no defrost interval.
2. Select a dFt value between 1 minute and 99 minutes. See Figure 9.
Control behavior when manually starting or stopping a Defrost
Off-Cycle
The controller enforces the following behavior:
• Manually start a Defrost Cycle. The control returns to normal On/Off operation after the defrost
cycle time (dFt) is complete.
• Manually stop a Defrost Cycle. The defrost cycle time (dFt) is terminated and the control is
returned to normal On/Off operation.
Manually starting and stopping a Defrost Cycle (SdF)
To manually Start/Stop a Defrost Cycle (SdF):
1. Select a Defrost Interval (dI) value of 0.
2. Select a dFt value between 1 minute and 99 minutes.
3. - Select an SdF parameter value of 1 during normal On/Off operation to start a defrost
cycle.
Figure 9: Typical passive Defrost Cycle behavior
A421 Series Electronic Temperature Controls with Off-Cycle Defrost Installation Guide 17