Carrier 38VH - Manual (Page 9)

8. Add charge by slowly opening Chargemaster
valve. If necessary, reduce charge by bleeding
at liquid line service valve. Check outdoor air
and evaporator temperature during procedure.
If they change, refer back to Chargemaster
Charging Chart.
Correct use of Chargemaster ensures than an opti­
mum refrigerant charge will be in system when
conditions and system components are “normal.”
However, the Chargemaster does not solve or fix
systems abnormalities. It indicates correct charge
for condition of the system. It will not make correc­
tions for dirty filters, slow fans, excessively long or
short suction lines or other abnormal conditions.
This charging device ensures that a correct relation­
ship exists between outdoor temperature, evap­
orator temperature, and suction line temperature
on a specific system.
SIGHT GLASS METHOD — (Field-supplied sight
glass installed in liquid line.) A satisfactory oper­
ating charge can be obtained on thermal expansion
valve systems only by charging to a clear sight glass.
For optimum charge, increase high-side pressure
to 380 ± lOpsig by blocking condenser fan dis-
eharge or air entering condenser. Charge to a clear
sight glass while holding constant high-side pres­
sure. For peak efficiency, adjust charge to yield a
liquid refrigerant temperature at the evaporator
that is approximately the same as outdoor dry-bulb
temperature.
SERVICE
Compressor Removal — See Table 9 for com­
pressor information and Fig. 6 for component
location. Shut off power to unit. Remove refrig­
erant from unit using refrigerant removal methods
described in Carrier Standard Service Techniques
Manual, Chapter 1, Refrigerants.
Follow safety codes. Wear safety glasses and
work gloves. Have quenching cloth available.
Table 9 — Compressor Data
UNIT
38VH
V/PH
PRODUCTION
COMPRESSOR*
OIL RECHARGE (oz)t
Typical Additional
001 208-230/1 ÂH8520E J
/
0 25
^ 002 208-230/1 CRB1-0175-PFV J/ 51 05
003 208-230/1 CRFI-0250'PFV-^
/
05
004 208-230/1 CRH1-0275;PFVv
1
05
045 208-230/1 AH8543E J , 42 05
005 230/1 PC5016BD y 72 1 0
•Refer to Carrier Service Parts Catalog for replacement com­
pressor model numbers
f'Typical ' refers to systems having refrigerant piping up to 50 ft
long Where piping exceeds 50 ft add additional quantity of oil
shown for e a c h 10 ft beyond 50 feet
2
.
1. Turn off power to unit. Failure to do so may
result in electric shock. Open door and remove
top access panel if so equipped. See Fig. 6.
Remove unit top cover. Remove 6 screws
holding fan motor orifice assembly in place.
Lift assembly and position it near unit being
careful not to strain fan motor ends.
3. Compressor sound shield is snapped together.
Undo those snaps which are under piping
connections, then lift the assembly off the
compressor.
4. Remove compressor terminal box cover. Dis­
connect and remove compressor power leads.
5. Be sure refrigerant has been removed so that
system pressure is 0 psig.
6. Using a tubing cutter, cut suction and discharge
lines at convenient place near compressor to
allow easy reassembly to new compressor by
using field-supplied copper coupling connected
at these points.
M iumy a break
7. Remove compressor hold-down bolts. Lift out
compressor thru front of unit.
8. Carefully unbraze suction and discharge line
piping stubs from compressor. If oil vapor in
piping stubs ignites, use quenching cloth.
9. Braze piping stubs (removed in Step 7) onto new
compressor.
10. Install new compressor in unit. Have fire ex­
tinguisher and/or quenching cloth available in
case oil vapor ignites. Braze suction and dis­
charge lines to compressor piping stubs (at
points where cut, Step 6) using field-supplied
copper couplings. Replace compressor hold­
down bolts. Reconnect wiring.
11. Clean system. If a compressor failure was
caused by a major motor-winding burnout,
contaminants (burnout by-products) can cause
future system operating problems if left in
system. Install a filter-drier in the suction line
near the compressor. Also install a drier in the
liquid line ahead of the refrigerant control
device. Run unit for 48 hours to remove con­
taminants. Remove suction line filter-drier
and liquid line drier. Discard both driers.
Clean AccuRater™ refrigerant control as de­
scribed in evaporator installation instructions.
Install new liquid line filter-drier. If burnout
was minor, install or replace liquid line filter-
drier, run for 48 hours, then discard filter-drier.
Install new filter-drier.