Thermo King RD-MT - Zone 1 Cool and Zone 2 Heat

Unit Description
34
Zone 1 Cool and Zone 2 Heat
The CIS is closed so high pressure refrigerant
vapor leaves the compressor and flows through
the Zone 2 hot gas line and the open RHGS into
the Zone 2 evaporator. There the refrigerant heats
the Zone 2 evaporator and condenses into high
pressure liquid. Because the RSLS is closed, the
liquid refrigerant flows through the RLRCV and
the liquid line to the LLS.
The LLS is open so the refrigerant flows through
the Zone 1 expansion valve into the Zone 1
evaporator. There the liquid refrigerant cools the
Zone 1 evaporator as it evaporates into low
pressure vapor. The refrigerant returns to the
compressor through the SLCV, and the
accumulator.
Zone 1 Evaporator
1F: Zone 1 Liquid Line Solenoid (LLS)—Open
2F: Zone 1 Liquid Return Check Valve (LRCV)—
Closed
3F: Zone 1 Suction Line Check Valve (SLCV)—
Open
4F: Zone 1 Suction Line Solenoid (SLS)—Open
5F: Zone 1 Hot Gas Solenoid (HGS)—Closed
Zone 2 Evaporator
1R: Zone 2 Liquid Line Solenoid (RLLS)—Open
2R: Zone 2 Liquid Return Check Valve
(RLRCV)—Open
3R: Zone 2 Suction Line Check Valve
(RSLCV)—Closed
4R: Zone 2 Suction Line Solenoid (RSLS)—
Closed
5R: Zone 2 Hot Gas Solenoid (RHGS)—Open
Condensing Unit
6: Condenser Inlet Solenoid (CIS)—Closed
7: Condenser Inlet Check Valve (CICV)—Closed
8: Condenser Check Valve (CCV)—Closed
9: Receiver Tank Pressure Solenoid (RTPS)—
Open/Closed (pressure dependant)
10: Purge Valve (PV)—Open
11: Purge Check Valve (PCV)—Open
Figure 4: Zone 1 Cool and Zone 2 Heat
AEA2087
Zone 2 Heat
Zone 1 Cool
Condensing Unit