Thermo King – Receiver Outlet Check Valve Test

Purpose: To check for a leak through the receiver outlet check valve.
1. Install a calibrated gauge manifold.
2. Install an additional compound gauge on the receiver tank outlet service port.
3. Confirm the 3-way valve shifts properly.
4. Verify the unit has a full refrigerant charge.
5. Operate the unit in high speed cool 5 minutes or more.
6. Adjust the thermostat to cycle the unit to the heat mode.
7. The unit should run 2 to 4 minutes in the condenser evacuation mode. Pressures will stabilize. **
8. Observe the additional compound gauge on the receiver tank and the receiver tank sight glass as the 3-way valve shifts to heat. Run in heat five minutes or more.
• The sight glass should remain empty.
• Receiver tank pressure should remain stable.

NOTE: A leaking receiver outlet check valve will cause a loss in heating capacity by allowing the refrigerant to flow into the receiver tank during the heat cycle. This will allow the sight glass to fill with refrigerant and the receiver tank pressure to increase.

**Some units have variations of or a modified TherMax cycle. An ambient switch may be in the TherMax solenoid circuit and the heat initiation timer may be disconnected or missing. These modifications will require manual control of the pilot solenoid and TherMax solenoid during system checkout.

Leave a Reply

Your email address will not be published. Required fields are marked *