Refrigeration Maintenance (Rev. 04/03)
72
2. Using a screwdriver, gently turn the check valve stem
in until the valve is front seated.
3. Install a service gauge manifold set on compressor.
4. Close (front seat) the receiver tank outlet valve.
5. Operate the unit on cooling, and pump down the low
side to 20 in. (-68 kPa) of vacuum.
6. Stop the unit. the condenser and suction pressures
should remain stable, indicating no leaks.
7. Shift the three-way valve to heat position. low side
gauge will raise slightly. High side gauge will drop to
approximately zero. Gauges will equalize.
8. Gauges will remain in this position (approximately
zero) if the three-way valve seals properly toward the
condenser and the condenser pressure bypass check
valve seals properly.
9. Back seat condenser pressure bypass check valve stem
against snap ring. Both gauges should rise indicating
the condenser pressure bypass check valve is properly
releasing condenser pressure into the discharge tube
and evaporator.
10. Replace the cap on the condenser pressure bypass
check valve.
NOTE: Valve stem MUST be back seated during nor-
mal unit operation.
11. Open the receiver tank return outlet valve, remove the
gauges and return the unit to normal operation.
Three-way Valve Condenser Pressure Bypass
Check Valve
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