LOW DISCHARGE PRESSURE
If the discharge pressure drops below the value of the setpoint #49 “LO DISCH PSI” and it remains there for
the time specifi ed in the safety time of that setpoint, the compressor’s safety will trip and a “LO DISCH PSI
#?” alarm will be generated.
HIGH DISCHARGE PRESSURE
If the discharge pressure raised above the value of the setpoint #47 “HI PSI ALARM” and it remains there for
the time specifi ed in the safety time of that setpoint, the compressor’s safety will trip and a “HI PSI ALARM #?”
alarm will be generated.
UNSAFE DISCHARGE PRESSURE
If the discharge pressure raised above the value of the setpoint #48 “UNSAFE DISCH” and it remains there
for the time specifi ed in the safety time of that setpoint, the compressor’s safety will trip and a “UNSAFE
DISCH #?” alarm will be generated.
HI COMP AMPS
Hi compressor amps safety is based on the calculated value of the setpoint #39 “HI COMP AMPS” times the
value of the compressor’s setpoint for FLA (setpoints #35 thru #38). If the ampere raises above the calculated
value and it remains there for the time specifi ed in the safety time of that setpoint, the compressor’s safety will
trip and a “HI COMP AMPS#?” alarm will be generated.
This safety is bypassed for the fi rst 3 seconds after a compressor is started.
LO COMP AMPS
Low compressor amps safety is based on the calculated value of the setpoint #40 “LO COMP AMPS” times
the value of the compressor’s setpoint for FLA (setpoints #35 thru #38). If the ampere falls below the calculated
value and it remains there for the time specifi ed in the safety time of that setpoint, the compressor’s safety will
trip and a “LO COMP AMPS#?” alarm will be generated.
This safety is bypassed for the fi rst 3 seconds after a compressor is started.
For a safety to be interrogated, both the associated sensor input and the lockout setpoint must be active. If a
safety trips, the alarm name will consist of the setpoint name plus a number indicating which condenser fan
tripped.
The following are a list of safeties that are incorporated in the MHRC control for condenser fans. These safeties
are checked every second. Each condenser fan is tested individually. If a safety condition exists, action will
be taken on that condenser fan only, other condenser fans will continue to function normally.
HI COND AMPS
Hi condenser fan amps safety is based on the calculated value of the setpoint #52 “HI COND AMP” times the
value of the condenser fan FLA setpoint #51. If the ampere raises above the calculated value and it remains
there for the time specifi ed in the safety time of setpoint #52, the condenser safety will trip and a “HI COND
AMPS#?” alarm will be generated. The condenser fan is locked out and must be reset manual via the LCD/
Keypad or MCS-CONNECT.
LO COND AMPS
Low condenser fan amps safety is based on the calculated value of the setpoint #53 “LO COND AMP” times
the value of the condenser fan FLA setpoint #51. If the ampere falls below the calculated value and it remains
there for the time specifi ed in the safety time of setpoint #53, the condenser safety will trip and a “LO COND
AMPS#?” alarm will be generated. The condenser fan is locked out and must be reset manual via the LCD/
Keypad or MCS-CONNECT.
39
21.6 Condenser Fan safeties
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