Z-1 Zone 1 Evaporator* (Host Unit): COOL
1. Liquid Line Solenoid (LLS) – Open
2. Liquid Return Check Valve (LRCV) – Closed
3. Suction Line Check Valve (SLCV) – Open
4. Suction Line Solenoid (SLS) – Open
5. Hot Gas Solenoid (HGS) – Closed
6. Condenser Inlet Solenoid (CIS) – Closed****
7. Condenser Inlet Check Valve (CICV) – Closed
8. Receiver Tank Pressure Solenoid (RTPS) –
Open****
9. Condenser Check Valve (CCV) – Closed
10. Bypass Hand Valve
11. Purge Valve (PV) – Open****
12. 12.Purge Check Valve (PCV) – Open
Z-2 Zone 2 Evaporator**: COOL
1C. Zone 2 Liquid Line Solenoid (LLS2) – Open
2C. Zone 2 Liquid Return Check Valve (LRCV2) –
Closed
3C. Zone 2 Suction Line Check Valve (SLCV2) –
Open
4C. Zone 2 Suction Line Solenoid (SLS2) – Open
5C. Zone 2 Hot Gas Solenoid (HGS2) – Closed
Z-3 Zone 3 Evaporator***: HEAT
1R. Zone 3 Liquid Line Solenoid (LLS3) – Open
2R. Zone 3 Liquid Return Check Valve (LRCV3) –
Closed
3R. Zone 3 Suction Line Check Valve (SLCV3) –
Open
4R. Zone 3 Suction Line Solenoid (SLS3) – Open
5R. Zone 3 Hot Gas Solenoid (HGS3) – Closed
*Also called Front Evaporator
**Also called Center Evaporator
***Also called Rear Evaporator
****NOTE: The controller opens and closes these
valves as required to control the head pressure.
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