Carrier 38AUD 16 Series - Page 50

50
APPENDIX A
Air Conditioner & Heat Pump with PURON

— Quick Reference Guide
S Puron

(R-410A) refrigerant operates at 50 percent to
70 percent higher pre ssures than R-22. Be sure t hat
servicing equipment and replacement c omponents are
designed to operate with Puron.
S Puron refrigera nt cylinders are rose colored.
S Recovery cylinder service pressure rating must be 400
psig, DOT 4BA400 or DOT BW400.
S Puron systems should be charged with liquid
refrigerant. Use a comm ercial t ype metering device in
the manifold hose when charging into suction line with
compressor operating.
S Manifol d sets should be 700 psig high side and 180 psig
low side with 550 psig low-side retard.
S Use hoses with 700 psig service pressure rating.
S Leak detectors should be designed to det ect HFC
refrigerant.
S Puron, as with other HFCs, is only compatible with
POE oils.
S Vacuum pumps will not remove moisture from oil.
S Use only factory specified liquid-line filter driers with
rated working pressures greater than 600 psig.
S Do not install a suction-line filter drier in liquid-line.
S POE oils absorb moisture rapidly. Do not expose oil to
atmosphere.
S POE oils may cause damage to certain plastics and
roofing materials.
S Wrap all filter driers and service valves with wet cloth
when brazing.
S A factory approved, liquid-line filter drier is required on
every unit.
S Do not use an R-22 TXV.
S If i ndoor unit is equipped with a TXV, it must be
changedtoaPuron

TXV.
S Never open system to at mosphere while i t is under a
vacuum .
S When system must be opened for service, recover
refrigerant, break vacuum with dry nitrogen before
opening system.
S Always replace filter drier after opening system for
service.
S Do not vent Puron

into the atmosphere.
S Do not use capillary tube coils.
S Observe all warnings, cautions,andbold te xt.
S All Puron

heat pumps must have indoor TXV.
S Do not leave Puron

suction line driers in place for
more than 72 hours.
APPENDIX B
Wiring Diagram List
Unit
Electrical
Characteristics
Diagram
Number
38AUD*16
208/230-3-60 38AU500540
460-3-60 38AU500541
575-3-60 38AU500542
38AUD*25
208/230-3-60 38AU500565
460-3-60 38AU500566
575-3-60 38AU500567
38AUZ*16
208/230-3-60 38AU500537
460-3-60 38AU500538
575-3-60 38AU500539
38AUZ*25
208/230-3-60 38AU500568
460-3-60 38AU500569
575-3-60 38AU500570
APPENDIX C
Low Ambient Option — Factory Installed
Units with the factory installed low ambient option are
equippe d with a Motormaster
R
solid--state head pressure
control which regulates fan speed. A temperature sensor,
mounted on circuit 1 of the outdoor coil (see Figs. 48 and
49) controls the speed of approved outdoor fan motors i n
order to ma intain a constant head pressure in t he outdoor
coil. T he control maintains the appropriate head pressure
at low ambient temperatures down to --20_F(--28_C).
Wind baffles are required t o prevent wind cross currents
from causing abnormall y low condensing temperatures.
S Use 20--gauge sheet metal to fabricate wind baffles (see
Fig. 51 and Table 15) and mounting brackets (see Fig.
52).
Note: Mounti ng brackets are for use on 15 ton model
units only.
S Instal l the wind baffles as show in Fig. 53, for 15 ton
units and Fig. 54, for 20 ton units .
Operation —
Fan on/off control in cooling--onl y units (38AUZ,
38AUD) is provided by an outdoor fan relay (OFR).
In cooli ng mode, fan motor speed of outdoor motors
OFM1 and OFM3 is regulated by the speed control
temperature sensor on outdoor coil 1 for a minimum coil
condensing temperature of approximately 100_F(38_C)
at higher outdoor ambient temperature and 80_F(27_C) at
lower ambient. Additionall y, outdoor fan motor OFM2
and OFM4 are turned on/off by the low ambient
temperature switch, LAS, operating the low ambient relay
38AU