Thermo King 098203, Maintenance Manual

Page: 159 / 264

Electrical Maintenance
157
Low Pressure Cutout Switch
A low pressure cutout switch is located on the compressor suction line. If the suction pressure becomes
too low, the switch opens to stop the compressor:
• Compressor stops immediately.
• Evaporator and condenser fans continue normal operation.
• Compressor will restart if the low refrigerant condition is corrected (switch closes) as long as power is
available. The low pressure switch resets (closes) when the pressure increases to 28 to 48 kPa, 0.28 to
0.48 bar, 4 to 7 psig.
Low Pressure Cutout Switch:
• Opens: -17 to -37 kPa, -0.17 to -0.37 bar, 5 to 11 in. Hg vacuum.
• Closes: 28 to 48 kPa, 0.28 to 0.48 bar, 4 to 7 psig.
Low Pressure Cutout Switch Removal
Remove the low pressure cutout switch by performing the following steps:
1. Disconnect the low pressure cutout switch wires from the control box.
2. Remove the low pressure cutout switch from the suction line. The fitting on the suction line has a
shrader valve which will prevent refrigerant leakage.
1. Low Pressure Cutout Switch
2. High Pressure Cutout Switch
3. Discharge Service Valve
4. Suction Service Valve
Figure 131: Low and High Pressure Cutout Switches
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