Troubleshooting guide

MAGNUM VERSION 8 MANUAL REVISION 3.1
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Purge Safety Switch SI - If this switch is on for longer than the value in Setpoint #164 “P-FaultTimer” all purge Relay
Outputs will be locked off and an error message will be generated. This will have no effect on the status of the unit.
Purge Suction Temp SI – This sensor provides the suction line temperature of the auxiliary unit. When a purge cycle
is active this temperature is monitored. If it remains above the value in Setpoint #163 “PurgeTarget” the compressor
will not exhaust any non-condensables from the purge drum. However, if the temperature drops below this value then
the exhaust pump and solenoids must be on to capture the non-condensables.
7.7.6.2. Conditions to Run Purge Cycle
Mode selection switch in AUTO position: The compressor must be running and the suction line temperature of
the auxiliary unit must be less than the value in Setpoint #163 “Purge Target”.
Mode selection switch in MANUAL position: The suction line temperature of the auxiliary unit must be less than
the value in Setpoint #163 “Purge Target”.
Mode selection switch in OFF position: purge cycles will not run.
7.7.6.3. Purge States
SWITCHED OFF – The mode selection switch is in the OFF position.
FLOAT FAULT - The purge safety switch has been on longer than the value in Setpoint #164 “Purge Fault”. All
purge Relay Outputs will be LOCKED OFF. When this switch returns to the normal off position, the purge Relay
Outputs will be changed to AUTO and the purge state will be either M-PRG OFF or A-PRG OFF.
M-PRG OFF – The mode selection switch is in the MANUAL position. All purge Relay Outputs are OFF. If the
suction line temperature of the auxiliary unit drops below the value in Setpoint #163 “PurgeTarget” the state will be
changed to M-PRG-RUNNING. Note, in this state the status of the compressor is not checked.
M-PRG RUNNING – The purge relay enable and the purge pump are turned on. The purge solenoid will be
turned on 1 second after the pump has started. If the suction line temperature of the auxiliary unit rises above the
value in Setpoint #163 “PurgeTarget” the purge solenoid will be turned off. 1 second later the purge relay enable and
the purge pump will be turned off and the state will be changed to M-PRG OFF,
A-PRG OFF - The mode selection switch is in the AUTO position. All purge Relay Outputs are OFF. If the
compressor is running and the suction line temperature of the auxiliary unit drops below the value in Setpoint #163
“PurgeTarget” the state will be changed to A-PRG-RUNNING. Note, in this state the status of the compressor is
checked.
A-PRG RUNNING - The purge relay enable and the purge pump will be turned on. The purge solenoid will be
turned on 1 second after the pump has started. If the compressor goes off or the suction line temperature of the
auxiliary unit rises above the value in Setpoint #163 “PurgeTarget” the purge solenoid will be turned off. 1 second later
the purge relay enable and the purge pump will be turned off and the state will be changed to A-PRG OFF.
7.7.6.4. Excess Purge Logic
Setpoint #165 “Excess Purge” typical Value = 20 Minutes
MIN = 1
MAX = 120
ADJ = 10
Time = 0
The MCS-MAGNUM accumulates the amount of minutes a purge enable relay has been on for the last 24hrs
(This is a rolling 24hrs window). If (purge enable accumulated on minutes) is greater than the value of Setpoint
#165 an “Excess Purge” alarm is generated and the Warning relay is turned on. The (purge enable accumulated
on minutes) counter is set to zero when a lockout reset has been performed by the user. The Warning light is
also turned off.