TriPac – Protection Devices

High System Pressure Cutout Switch

The High System Pressure Cutout Switch is a normally closed system pressure sensitive switch.

On models manufactured prior to 9/06, it is part of the binary pressure switch, mounted on the receiver-drier, typically near the TriPac condenser. On models manufactured during 9/06 and after, a High Pressure Cutout Switch (HPCO) is located at the receiver/drier.

If the discharge pressure rises above the switch’s opening pressure, the switch opens the circuit to stop the unit and generates an AcS Alarm Code. The opening pressure for the binary switch is 325 psig (2241 kPa). The opening pressure for the HPCO is 400 psig (2758 kPa).

When the discharge pressure falls below the switch’s closing pressure, the switch closes to allow compressor operation. The closing pressure for the binary switch is 230 psig (1586 kPa). The closing pressure for the HPCO is 325 psig (2241 kPa).

Low System Pressure Cutout Switch

The Low System Pressure Cutout Switch is a normally closed pressure sensitive switch.

On models manufactured prior to 9/06, it is part of the binary pressure switch, mounted on the receiver-drier, typically near the TriPac condenser. On models manufactured during 9/06 and after, a Low Pressure Cutout Switch (LPCO) is installed at the evaporator coil.

If the pressure falls below the switch’s opening pressure, the switch opens the circuit to stop the compressor. The opening pressure for the binary switch is 22.5 psig (155 kPa). The opening pressure for the LPCO is 5 psig (34 kPa).

When the pressure rises above the switch’s closing pressure, the switch closes to allow compressor operation. The closing pressure for the binary switch is 40 psig (276 kPa). The closing pressure for the LPCO is 20 psig (138 kPa).

Fuse Protection

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The electrical system is protected by a number of fuses (see “Fuses” on page 18). Most of the fuses are located on the interface board shown above, or in the control box near the interface board.

Engine Reset Switch

The engine is protected by a reset switch. When the reset switch opens the engine will shut down. Typical causes for an open engine reset switch are low oil pressure, high water temperature or an engine start failure. The engine reset switch is located on the side of the Interface Board control box enclosure.

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