To: Service Contractors responsible for PM Service and Repair and Cell Technicians
Subject: Achieving temporary mechanical cooling without controller input.
Background: Emergency wiring allows the Wall Packaged Units to achieve temporary mechanical cooling without controller input. Emergency wiring should ONLY be used after troubleshooting with HVAC Support Line (805-879-5432) or in the event that Support Line cannot be reached and mechanical cooling is required immediately to prevent equipment failure. Emergency wiring bypasses internal protection mechanism and should never be used as a long term solution. Use of emergency wiring under any condition except stated herein will void warranty.
There are 2 options for emergency cooling:
1. Continuous Cooling (hardwired-ON)
2. Thermostat Temperature Controlled
Instructions:
All Emergency wiring must be by performed by professional technicians.
Danger! Risk of electric shock can cause serious injury or death.
Switch the breakers off to both HVAC units AND the controller before adding emergency wiring.
Option 1: Continuous Cooling (w/o Thermostat)
Add a jumper wire between 400 and 1 (Compressor relay signal).Add a jumper wire between 400 and 2 (Evaporator fan relay signal).
Add a jumper wire between L and 4 (230VAC signal return).
Add a jumper wire between 11 and +10V (This enables supply fan).
Verify all wires are connected exactly as specified
Turn all AC breakers on and the system should start cooling.
Option 2: Thermostat Temperature Controlled (Mechanical or Digital, residential type OK)
Note: The Thermostat can be very light duty (Min contact rating 220VAC), as it is sustaining an extremely low relay control signal current of < 200mA total.
Add a jumper wire between 400 and 2 (evaporator fan relay signal).
Add a jumper wire between L and Rc.
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Rc is also known as Cooling Voltage.
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Y is also known as Switch for Cooling.
Verify all wires are connected exactly as specified.
Turn all AC breakers on and the system should start cooling.
