Indoor Coil; Refrigeration System Components; Reversing Valve And Check Valve Position; Troubleshooting Refrigerant Pressure Problems And Check Valves - Carrier WeatherMaster 50HCQ04-12 Service And Maintenance Instructions

CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in accelerated cor-
rosion of unit parts.
Harsh chemicals, household bleach or acid or basic clean-
ers should not be used to clean outdoor or indoor coils of
any kind. These cleaners can be very difficult to rinse out of
the coil and can accelerate corrosion at the fin/tube inter-
face where dissimilar materials are in contact. If there is
dirt below the surface of the coil, use the Totaline environ-
mentally sound coil cleaner.
TOTALINE ENVIRONMENTALLY
CLEANER APPLICATION INSTRUCTIONS
1. Proper protection equipment, such as approved safety
glasses and gloves, is recommended during mixing and
application.
2. Remove all surface loaded fibers and debris using a vac-
uum cleaner or a soft non-metallic bristle brush as
described above.
3. Thoroughly wet finned surfaces with clean water and a
low velocity garden hose, being careful not to bend fins.
4. Mix Totaline environmentally sound coil cleaner in a 2.5
gal (9.5 L) garden sprayer according to the instructions
included with the cleaner. The optimum solution tempera-
ture is 100° F (38° C).
NOTE: DO NOT USE water in excess of 130° F (54° C), as
the enzymatic activity will be destroyed.
1. Thoroughly apply Totaline environmentally sound coil
cleaner solution to all coil surfaces including finned area,
tube sheets and coil headers.
2. Hold garden sprayer nozzle close to finned areas and apply
cleaner with a vertical, up-and-down motion. Avoid spray-
ing in horizontal pattern to minimize potential for fin dam-
age.
3. Ensure cleaner thoroughly penetrates deep into finned
areas. Interior and exterior finned areas must be thor-
oughly cleaned. Finned surfaces should remain wet with
cleaning solution for 10 minutes. Ensure surfaces are not
allowed to dry before rinsing. Reapply cleaner as needed
to ensure 10-minute saturation is achieved.
4. Thoroughly rinse all surfaces with low velocity clean
water using downward rinsing motion of water spray noz-
zle. Protect fins from damage from the spray nozzle.

Indoor Coil

CLEANING THE INDOOR COIL
1. Turn unit power off. Use proper lockout/tagout proce-
dures.
2. Remove indoor coil access panel.
3. If economizer or two-position damper is installed, remove
economizer by disconnecting the Molex
ing mounting screws.
4. Slide filters out of unit.
5. Clean coil using a commercial coil cleaner or dishwasher
detergent in a pressurized spray canister. Wash both sides
of coil and flush with clean water. For best results, back-
flush toward return-air section to remove foreign material.
Flush condensate pan after completion.
6. Reinstall economizer and filters.
7. Reconnect wiring.
8. Replace access panels.
1. Molex is a registered trademark of Molex Inc.

Refrigeration System Components

Each heat pump refrigeration system includes a compressor,
accumulator, 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 head-
er check valve, and heating liquid line with check a valve and a
strainer. Unit sizes A04-A/D07 have a single compressor-cir-
cuit; unit sizes D08-D12 have two compressor-circuits. See
Fig. 15 for typical unit piping schematic (unit size D09 (4-row
indoor coil) with two compressor-circuits is shown).
Dual-function outdoor and indoor coils are designed to provide
parallel coil circuits during evaporator-function operation and
converging coil circuits during the condenser-function operation.

Reversing Valve and Check Valve Position

SOUND COIL
See Fig.15.
Troubleshooting Refrigerant Pressure Problems
and Check Valves
Refer to Fig. 15 and the Cooling, Heating, and Defrost Mode
Tables 3-5).

Refrigerant System Pressure Access Ports

There are two access ports in each circuit - on the suction tube
and the discharge tube near the compressor. These are brass fit-
tings with black plastic caps. The hose connection fittings are
standard
1 plug and remov-
The brass fittings are two-piece High Flow valves, with a recep-
tacle base brazed to the tubing and an integral spring-closed
check valve core screwed into the base. See Fig. 16. This check
valve is permanently assembled into this core body and cannot
be serviced separately. Replace the entire core body if necessary.
Service tools are available from RCD that allow the replacement
of the check valve core without having to recover the entire sys-
tem refrigerant charge. Apply compressor refrigerant oil to the
check valve core's bottom O-ring. Install the fitting body and
torque to 96±10 in.-lbs (10.9 ± 1 Nm). Do not exceed 106 in.-lbs
(11.9 Nm) when tightening.
10
Table 3 — Cooling Mode (each circuit)
COMPONENT
Reversing Valve
Check Valve A
Check Valve B
Check Valve C
Check Valve D
Table 4 — Heating Mode (each circuit)
COMPONENT
Reversing Valve
Check Valve A
Check Valve B
Check Valve C
Check Valve D
Table 5 — Defrost Mode
(A04-A/D07 and D08-D12/Circuit 2:)
COMPONENT
Defrost Thermostat
Outdoor Fan(s)
Reversing Valve
Check Valve A
Check Valve B
Check Valve C
Check Valve D
/ SAE male flare couplings.
1
4
STATUS/POSITION
Energized
Closed
Open
Closed
Open
STATUS/POSITION
De-energized
Open
Closed
Open
Closed
STATUS/POSITION
Closed
Off
Energized
Closed
Open
Closed
Open