Carrier 38EV024320 - Manual (Page 42)

d) Cut thermistor leads about 12" back from end. Cut
replacement thermistor leads to about 16" long, strip
back all leads, and splice leads together with a crimp-
type connector. Use silicone sealer in connector to
make it waterproof.
e) Re-insert thermistor into %e" tube, retain with (1) plas­
tic tie around wires and refrigerant tube. Be sure
thermistor is not sticking out end of tube. Fill both
ends of small tube with petroleum jelly and similar.
f) Wrap thermistor tube with same 3" piece of armaflex
insulation, or similar. SUt of foam insulation must be
on opposite side of refrigerant tube from thermistor
;weU. -Tie in-place-with (2) plastic-ties-as-before. -----—
CONTACTOR REPLACEMENT
Break power to indoor and outdoor units, and remove con­
trol box cover.
a) Disconnect aU wires to contactor noting attach point to
component. Refer to unit wiring diagram. Loosen upper
left mounting screw and remove lower right screw.
Remove contactor and replace.
b) Rewire contactor following unit wiring diagram.
A CAUTION
Make sure contactor wiring is correct before starting
unit. Left side of contactor (terminals #11 and #21) of
contactor is for 230 VAC input power. Right side (ter­
minals #13 and #23) is 300 VDC supply to inverter
board (violet wires).
EMERGENCY STOP SWITCH (ESS) REPLACEMENT
(38EV036 and 38QV036 Only)
a) Break power to indoor and outdoor units.
b) ESS .switch is in series with low pressure switch arid is
connected with wire nuts within the compressor junc­
tion box. Remove unit top grille and compressor sound
shield. Switch is located on top of compressor under a
special rnetal clip with white wires going to junction
box.
b) Push switch (rectangular aluminum body) toward wire
end and it will slip out from under clip.
c) DO NOT remove wires from compressor junction box.
Cut white wires about 6" out of box.
d) Slidé new switch under clip until it hits stop at end of
i . cHp. '
' i " : ' ; - V ■
e) Re-wire switch to old white wires out of compressor
junction box with wire nuts. Note wires are #20 gage so
use appropriate nuts. Fill connector cavity with sili­
cone sealer.
f) Replace sound shield and top grille.
EXPANSION VALVE COIL REPLACEMENT
a) Break power to indoor and outdoor units. For outdoor
SEV replacement, remove top grille.
b) Reiriove nut holding solénoid on body of valve. Cut
wires about 12" away from coil.
c) Replace with new solenoid. Cut leads of new coil to
about 16" long. Splice with crimp-type connectors.
Reinstall nut and harness wires as before. Use silicone
sealer in connector cavity.
d) Replace top grille (for outdoor SEV replacement).
ELECTRONIC.EXPANSION VALVE REPLACEMENT
38QV OUTDOOR UNIT-
See Figs. 2 and 3 for Locations of Outdoor Unit SEV.
a) Break power to indoor and outdoor units.
b) Remove top grille.
c) Remove system charge using proper procedures.
d) Remove solenoid coil. Using two (2) wrenches, loosen
the flare nuts holding valve to tube. USE CARE to not
twist tubing. Remove valve. Remove piston as you
would in a standard unit when piston is in service
valve.
e) Insert same piston or new piston and new retainer in
new valve. Set valve in liquid line and hand-tighten
flare nuts. Tighten nuts to 10-15 lb. ft. Note: Use care
to not overtighten valve connections, which could
deform valve and bind pistons. This valve must be
mounted with coil in a vertical position as on original
installation. Piston must be at valve end toward serv­
ice valve, with arrow on valve body toward coil. Rein­
stall solenoid coil, and top grille.
f) Recharge system.
Indoor Location—
The indoor SEV valve is located on the liquid line at the
indoor coil.
38QV Heat Pump Systems—foUow procedure for outdoor
unit SEV replacement, above. When installed, new valve
should have arrow on body toward indoor unit, accurator
piston end facing toward outdoor unit.
38EV Cooling Systems—
a) Break power to indoor and outdoor units.
b) Remove system charge using proper procedures.
c) Remove thermistor insulation by cutting tie wraps.
Cut tie wrap securing thermistor leads to line, and slide
thermistor out of well.
d) Remove solenoid coil. Using two (2) wrenches loosen
flare nuts holding valve assembly in place. Use care not
to twist indoor unit fitting. Remove valve assembly.
e) Carefully unbraze valve from assembly tubes and braze
in new valve.
f) Set valve in Hne and hand-tighten flare nuts. Tighten
nuts to 25-30 Ib-ft.
g) Reinstall thermistor, insulation, and solenoid coil.
h) Recharge system.
INTERFACE CABLE-
a) Break-power to outdoor and indoor units.
b) Disconnect interface cable from outdoor unit control
board by sliding locking latch to right. Disconnect
ground wire. Loosen black plastic nut on cable strain
relief and remove cable from slot in box. The new cable
will have a new strain relief attached.
c) Disconnect interface cable from indoor interface con­
trol box by squeezing the metal tabs on the cable end.
Unfasten cable black ground wire with ring terminal
from sheet metal screw. Route cable out through hole
provided in cabinet.
d) Remove ALL ties securing cable to refrigerant lines
and remove cable from instaflation.
e) Connect new interface cable to outdoor unit control
board. This cable is polarized so it will only go on one
way. Slide metal retainer left to retain cable. Reattach
black ground wire to sheet metal screw. Loosen black
plastic strain relief nut on cable, set in slot on box and
tighten nut. Use care to not put excess strain on con­
trol board.
f) Working from outdoor to indoor unit, secure cable to
refrigerant lines every 2-3 ft. using tie wraps, or
similar.
g) Connect cable to indoor interface control board. Route
cable through holes provided in unit as before. This
cable end is also polarized so it will only go on one way.