Condensate Overflow Switch

FORM 145.15-IOM7 (412)

described above), the microprocessor control board will continue to monitor the low-pressure limit switch for any openings. If the low-pressure switch opens for greater than 5 seconds, the microprocessor control board will de-energize the compressor, initiate the ASCD, and stop the fan.

If the call for cooling is still present at the conclusion of the ASCD, the microprocessor control will re- energize the compressor.

Should a low-pressure switch fault three (3) times within one (1) hour of operation, the microprocessor control board will lock-out the compressor and flash a fault code indicating a low-pressure lock-out.

A Condensate Overflow fault occurs when the Condensate Overflow switch opens for more than two line cycles. The compressor is shutdown regardless of Minimum Run Time, ASCD is initiated, and alarm is tripped. The fan continues operating in its current state. Compressor will re-energize once the Condensate Overflow switch closes, and ASCD has been satisfied and a call for cooling is still present.

The microprocessor control board logs the first incident per compressor request. If the compressor request is removed, the fault occurrence counter is reset to zero. Should the Condensate Overflow switch open three within two hours of run time, the microprocessor control board will lock-out the compressor, turn off the fan and flash a fault code indicating a Condensate Overflow lock-out.

SAFETY CONTROLS

The microprocessor control monitors the following inputs:

1.A High-Pressure Switch on each compressor circuit to protect against excessive discharge pressures.

2.A Low-Pressure Switch on each compressor circuit to protect against loss of refrigerant charge.

3.A Condensate Overflow Switch to protect against condensate overflow.

Compressor Protection

In addition to the external pressure switches, the compressor also has inherent (internal) protection. If there is an abnormal temperature rise in a compressor, the internal protection will immediately shut down the compressor. The microprocessor control incorporates features to minimize compressor wear and damage. An anti-short cycle delay (ASCD)

is utilized to prevent short cycling of the compressor. Additionally, a minimum run time is imposed any time a compressor is energized. The ASCD is initiated on unit start-up and on any compressor reset or lockout.

Microprocessor Control Unit Flash Codes

Various flash codes are utilized by the microprocessor control to aid in troubleshooting. Flash codes are distinguished by the short on and off cycle used (approximately 200ms on and 200ms off). To show normal operation, the control boards flash a 1 second on, 1 second off “heart beat” during normal operation. This is to verify that the microprocessor is functioning correctly. Do not confuse this with an error flash code. To avoid confusion the 1-flash, fault code is not used.

24	JOHNSON CONTROLS