Refrigeration System Components; Reversing Valve And Check Valve Position; Troubleshooting Refrigerant Pressure Problems And Check Valves - Carrier 50HCQ12 Installation Instructions Manual

LOCATION DIMENSION
48-in. (1219 mm)
18-in. (457 mm)
A
18-in. (457 mm)
12-in. (305 mm)
42-in. (1067 mm)
36-in. (914 mm)
B
Special
36-in. (914 mm)
C
18-in. (457 mm)
42-in. (1067 mm)
36-in. (914 mm)
D
Special
NOTE: Unit not designed to have overhead obstruction. Contact Application Engineering for guidance on any application planning overhead
obstruction or for vertical clearances.

REFRIGERATION SYSTEM COMPONENTS

Each heat pump refrigeration system includes a compressor, accu-
mulator, reversing valve, dual-function outdoor coil with vapor
header check valve, cooling liquid line with a filter drier and a
check valve, dual-function indoor coil with a vapor header check
valve, and heating liquid line with a check valve and a strainer.
Size 12 units have two compressor-circuits. See Fig. 4 for typical
unit piping schematic (4-row indoor coil with two compressor-cir-
cuits is shown).
Dual-function outdoor and indoor coils are designed to provide
parallel coil circuits during evaporator-function operation and con-
verging coil circuits during the condenser-function operation.

Reversing Valve and Check Valve Position

See Fig. 4 and Tables 2-4.
Table 2 — Cooling Mode (Each Circuit)
COMPONENT
Reversing Valve
Check Valve A
Check Valve B
Check Valve C
Check Valve D
C
B
Unit disconnect is mounted on panel
No disconnect, convenience outlet option
Recommended service clearance
Minimum clearance
Surface behind servicer is grounded (e.g., metal, masonry wall)
Surface behind servicer is electrically non-conductive (e.g., wood, fiberglass)
Check sources of flue products within 10-ft (3 m) of unit fresh air intake hood
Side condensate drain is used
Minimum clearance
Surface behind servicer is grounded (e.g., metal, masonry wall, another unit)
Surface behind servicer is electrically non-conductive (e.g., wood, fiberglass)
Check for adjacent units or building fresh air intakes within 10-ft (3 m) of this unit's flue outlet
Fig. 3 — Service Clearance Dimensional Drawing
STATUS/POSITION
Energized
Closed
Open
Closed
Open
A
CONDITION
Table 3 — Heating Mode (Each Circuit)
COMPONENT
Reversing Valve
Check Valve A
Check Valve B
Check Valve C
Check Valve D
Table 4 — Defrost Mode
COMPONENT
Defrost Thermostat
Outdoor Fan(s)
Reversing Valve
Check Valve A
Check Valve B
Check Valve C
Check Valve D
Troubleshooting Refrigerant Pressure Problems
and Check Valves
Refer to Fig. 4 and the Cooling Mode and Heating Mode tables
(Tables 2 and 3).
6
D
STATUS/POSITION
De-Energized
Open
Closed
Open
Closed
STATUS/POSITION
Closed
Off
Energized
Closed
Open
Closed
Open