Heatcraft BOHN MAC8X User Manual

42
Diagnostics
PROBLEM Step ACTION ITEM IF OK IF NOT OK
1. Check wiring connection to the board • Correct eld wiring to the board
2. Low Pressure Safety (LPS) Tripped:
• Check for correct refrigerant type • Change setpoint to match refrigerant
• Check refrigerant charge • Add more refrigerant to proper charge
• Check LPS setting • Correct LPS setting
• Check LPS wiring • Correct LSP wiring
• Check EEV operation (stuck?) • Clean or replace EEV
• Check coil for icing • Defrost coil (see E6, step 2)
• Check for correct superheat reading • Check/replace sensor or transducer
• Check for correct nozzle selection • Replace distributor nozzle
• Check for clogged EEV inlet screen • Replace EEV
• Check line sizing • Correct line sizing
• Check LPS time delay relay setting • Reset to 1 minute
• Check operation of LPS • Replace Low Pressure Safety Switch
3. High Pressure Safety (HPS) Tripped:
• Check for system overcharge • Reclaim/recover excess charge
• Check for non-condensables • Remove all non-condensables
• Check condenser fan motor and blade • Repair or replace motor and/or blade
• Check for dirty condenser coil • Clean condenser coil
• Check head pressure controls • Adjust or replace faulty controls
• Check fan cycling controls • Adjust or replace faulty controls
• Check liquid line sizing • Correct line sizing
• Check for liquid line restrictions • Repair line or remove restrictions
• Check operation of HPS • Replace HPS if necessary
E7 Compressor 4. Oil Pressure Safety (OPS) Tripped:
Shutdown • Check oil level in compressor • Add oil to crankcase to minimum level
• Check oil sump screen pickup • Clean or replace pickup screen
• Check oil pump pressure • Replace compressor oil pump
• Check for proper piping practices Go to • Correct piping to minimize oil logging
• Check for low superheat (see E6) next step • Correct per steps in E6
• Check operation of auxiliary relay (R6) • Replace auxiliary relay
• Check OPS sensor • Replace faulty OPS sensor
• Check operation of OPS • Replace faulty OPS
5. Compressor Module Tripped (when supplied):
• Check module • Replace faulty module
• Check superheat at compressor inlet • Reduce superheat (TXV adjust, etc.)
• Check compressor for overheating • Correct overheating problem
• Check suction pressure (too low?) • Consider crankcase pressure regulator or
other measures
6. Phase Loss Monitor (PLM) Tripped:
• Check presence of all phase legs • Correct power phase problem
• Check power supply • Correct power supply problems
• Check operation of PLM • Replace faulty PLM
7. Demand Cooling (when supplied):
• Check auxiliary relay • Replace auxiliary relay
• Check demand cooling device • Replace faulty demand cooling device
8. Check compressor relay on board • Replace board if relay is faulty
Beacon II Troubleshooting Guide (continued)

Heatcraft BOHN MAC8X Specifications

General

Brand	Heatcraft
Model	BOHN MAC8X
Category	Heat Pump
Language	English