Carrier 38QF - Manual (Page 4)

WARNING: If unclcrsi7ed. damaged or
elliptiv.-all\-s!iapL'd uibing is used when making
Compatible bitting, leaks ma\ result.
If 1-1/8 in. tubing is used, braze it to the accessory
1-1/8 X 3/4-in. suction connection adapter (Carrier
Part No. 28VQ900011) or to a correctly sized field-
supplied adapter, then make Compatible Fitting
connections. Isolate interconnecting tubing from
framing and ductwork or where tubing runs thru
stud spaces, enclosed ceilings or pipe chases. Use
isolation type hangers. Fig. 3, since rigid fastening
transmits pulsations to structure creating objec­
tionable sound.
^ ( \l 1 ION. IK) \OI Ml \<\ MORI I II \\
'' I I ()l I INI SI I IN (.ROl N1). II .m> '•ac­
tion of liucsel is burictl. there must be b-in.
\ertical rise to the \al\e connections on the
outdoor unit. If more than the recommended
length i.s buried, refrigerant ma\ migrate to the
eooler buried .section during extended periods of
unit shutdown, causing relrigerant slugging and
possibh compressor damage at start-up.
A capacity reduction will result if accessory tub­
ing is used in 38QF systems. For example, when a
25-ft 7/8-in. accessory package is used, there is a
capacity reduction of 1-1/2 percent.
When other than 25 ft of interconnecting tubing
is used, follow special requirements described in
Refrigerant Charging. Do not use less than 10 ft of
interconnecting tubing. Do not cut 7/8-in. suction
line. Bend or coil to fit.
Do not use damaged or contaminated tubing.
Always evacuate or purge evaporator coil and
tubing system (use field-supplied refrigerant, not
unit refrigerant).
When making tubing connections, be sure to
provide clearance at unit for electrical connections.
REPLACE THE ACCURATER™ REFRIG­
ERANT CONTROL PISTON IN THE INDOOR
COIL AS REQUIRED before connecting refrig­
erant lines. See Table 1. Correct piston is supplied
with 38QF unit. For piston replacement instruc­
tions, see AccuRater Servicing on page 13.
CONNECT REFRIGERANT LINES to fittings on
unit suction and liquid service valves (Fig. 1).
Liquid service valve has flare fitting; suction service
valve has Compatible Fitting. Make suction line
connection first. Slide flare nut on liquid line, then
flare and connect liquid line. Use a maximum
torque of 15 ft-lb to tighten flare nut. (Do not dis­
assemble AccuRater.) Unit Compatible Fitting
permits mechanical or sweat connection as de­
scribed below.
When a 7/8-in. field-supplied suction line is
used on 38QF, a field-supplied 3/4-in. to 7/8-in.
suction line adapter must be provided (not required
if 38LS accessory tubing is used).
When a 1-1/ 8 in. field-supplied suction line is used
on 38QF, use accessory adapter 28VQ900011 or
other field-supplied connection. Sweat connect re­
frigerant suction line to 1-1/8 in. end of adapter.
Connect 3/4-in. end of adapter to unit suction line
Compatible Fitting.
Mechanical Connection to Compatible Fitting
(Mate one set of connections at a time.)
1. Loosen nut on Compatible Fitting one turn. Do
not remove.
2. Remove plug and be sure 0-ring is in the groove
inside the Compatible Fitting.
3. Cut tubing to correct length.
4. Insert tube into Compatible Fitting until it
bottoms.
5. Tighten nut until it bottoms on back coupler
flange. Keep tube bottomed in Compatible
Fitting while tightening nut.
Sweat Connection to Compatible Fitting (Use
refrigerant grade tubing.)
1. Remove locking nut, rubber O-ring and Schrader
core from valve.
2. Cut tubing to correct length.
3. Insert tube into Compatible Fitting. Wrap top
and bottom of service valves in wet cloth to pre­
vent damage by heat. Solder with low tempera­
ture (430 F) silver alloy solder.
4. Replace Schrader core.
5. Evacuate or purge system with field-supplied
refrigerant.
Step 4 — Make Electrical Connections — Field
wiring must comply with local and national fire,
safety and electrical codes. Voltage to unit must be
within permissible limits indicated on nameplate.
Contact local power company for correction of
improper line voltage.
W.AR.NTNG: Operation of units on improper
line \oliagc constiiiitcs abuse and could affect
Carrier warrantx. See fable4.
Do not apply units in system where voltage may
fluctuate above or below permissible limits.