Johnson Controls PC090 THRU 240, PD 180 THRU 240 dimensions Defrost Operation, Blower Operation

430645-YIM-D-0610

Defrost Operation

The defrost control board (DC) utilizes a time/temperature defrost scheme. The DC repeats normal heating run cycles, which must be completed, until one of the following conditions is met and the DC enters defrost mode:

1.The DC satisfies its accumulated minimum run time. This is factory set at 60 minutes, but is field adjustable to 30, 60 or 90 minutes.

2.The defrost switch(es) is closed. This normally open switch is set to close at 28° F (+/-3°).

When the DC enters defrost mode, its on-board defrost relays are powered. This energizes the reversing valve solenoid, de- energizes the condenser fan motors and energizes the unit's optional electric heater. The DC remains in defrost mode until either of the following two conditions are met:

1.Both of the liquid line thermostats are open. Each is set to open at 55 degrees (+/- 3).

2.The maximum defrost run time of 10 minutes is met.

The DC also contains a set of test pins. Placing a jumper across these pins will result in the following actions:

•If the ASCD timer is active, it is now bypassed, allowing the compressor to run.

•If the DC is in a lockout condition, the lockout is reset.

•If the compressor is running, the DC is forced into defrost mode. The control will remain in defrost mode as long as the jumper is in place. When the jumper is removed, the control will terminate defrost mode.

Table 10: PC090 thru 240 Unit Control Board Flash Codes

NOTE: The DC has two flash codes that only initiate if the jumper between the two pressure switch terminals is removed or broken.

Blower Operation

After completing the specified time for fan on-delay, UCB closes the coil of relay BR1.

•Relay BR1 sends a 24V signal to G1 of terminal block TB2. It may be used to control operation of an indoor blower.

The UCB disables the signal to BR1 after completing the fan off-delay period.

	Rear	Rear
2	2	4

1	1	3
	Front	Front

Figure 9: Fan Orientation, Control Box End

		GREEN	RED	RED	RED	RED
FLASH CODE	DESCRIPTION	LED	LED	LED	LED	LED
		16	8	4	2	1
On Steady	This is a Control Failure	-	-	-	-	-
1 Flash	Not Applicable	-	-	-	-	-
2 Flashes	Control waiting ASCD1	Flashing	Off	Off	On	Off
3 Flashes	HPS1 Compressor Lockout	Off	Off	Off	On	On
4 Flashes	Not Applicable	-	-	-	-	-
5 Flashes	LPS1 Compressor Lockout	Off	Off	On	Off	On
6 Flashes	Not Applicable	-	-	-	-	-
7 Flashes	FS1 Compressor Lockout2	Off	Off	On	On	On
8 Flashes	Not Applicable	-	-	-	-	-
10 Flashes	Compressors Locked Out on Low Outdoor Air Temperature1	Flashing	On	Off	On	Off
12 Flashes	Unit Locked Out due to Fan Overload Switch Failure	Off	On	On	Off	Off
13 Flashes	Compressor Held Off due to Low Voltage1	Flashing	On	On	Off	On
14 Flashes	EEPROM Storage Failure	Off	On	On	On	Off
OFF	No Power or Control Failure	Off	Off	Off	Off	Off

1.Non-alarm condition.

2.Freeze - stat not applicable.

Johnson Controls Unitary Products 21