82
TK 61555-2-MM-EN
High Pressure Cutout Switch (HPCO)
The High Pressure Cutout Switch (HPCO) is located on the compressor discharge manifold. If the
discharge pressure rises above 470 psig (32.41 bar), the HPCO opens the HPCO circuit to the run
relay and stops the unit. To test the HPCO, rework a gauge manifold as shown () and use the
following procedure:
1.
Connect the gauge manifold to the compressor discharge service valve with a heavy duty,
black jacketed thick wall #HCA 144 hose with a 900 psig (62.04 bar) working pressure rating.
2.
Use the Service Test Mode to run the unit (or host unit) in high speed cool.
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3.
Raise the discharge pressure of the compressor by blocking the condenser coil air flow by
covering the condenser grilles with pieces of cardboard. This should increase the discharge
pressure enough to cause the HPCO to cut out.
4.
If the HPCO does not open to de-energize the run relay and stop the unit, it must be replaced.
Figure 62.
High Pressure Cutout Manifold
1.
Relief Valve (66-6543)
2.
O-Ring (33-1015)
3.
Adapter Tee Weather Head No. 552X3
