Hussmann proto-aire Manuel De Montage

Protocol™ Installation and 

Service Manual 

7. Momentarily 

turn 

ON compressor breaker #1 and verify correct pumping direction.  

Check all compressors before switching any wires.  If all compressors are rotating 
backwards, change two legs at the field side of the convenience switch.  For 
individual compressor, change the Legs on the load side of the compressor 
contactor. 

 

Final Checks 
 
Return Gas Superheat 
 

Return gas superheat should be 10 to 30 °F on all units 

 
Once system is up and running, it is the responsibility of the installer to see that all the final 
adjustments are made so the Protocol™ delivers maximum temperature performance and 
efficiency for the customer.  These include: 
 
 

Thermostatic Expansion Valve superheat adjustment 

 

Electronic Pressure Regulator settings 

 

Defrost scheduling and timing 

 

Condenser flow balance 

 

High and low pressure controls 

 Thermostat 

settings 

 

Adjustments to electronic controls 

 

Electronic oil level controls 

 
Thoroughly inspect all field piping while the equipment is running and add supports where 
line vibration occurs.  Be sure additional supports do not conflict with pipe expansion and 
contraction. 
 
When merchandisers are completely stocked, check the operation of the system again. 
 
At 90 days recheck the entire system, including all field wiring. 
 

Never run the compressors in a vacuum as 
this may quickly damage the compressors. 

 
 
 
 
Control Settings 
 
High Pressure Safety – 395 psig 
Vacuum Pressure Safety – 0 psig 
Discharge Temperature Sensor – 240 °F 
 
It is mandatory that the mechanical low-pressure controls be set in the field 
 
Electronic Oil Level Control 
 

 

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