Carrier 38CQ - Manual (Page 6)

3-PHASE
CONN. TO
FUSED
DISCONNECT
_________
BLK-
I-PHASE
CONN. TO
FUSED
DISCONNECT
BLK-
YEL OR BLK------
L ------------ GROUND LUG
38CQ HEAT PUMP
CONTROL BOX
Fig. 7 — Line Power Connections
Use indoor unit transformer as 24-v supply for
system. At least a 60-va transformer is recom­
mended. Carrier approved indoor units are
equipped with 60-va transformer. See indoor unit
data.
Use Carrier accessory indoor thermostat
HH07AT071 with HH93AZ073 or HH93AZ075
subbase.
IWITIAL START-UP
The 38CQ unit is equipped with a crankcase
heater. It is recommended that heater be energized
a minimum of 24 hours before starting unit. To
energize heater only, turn the thermostat to OFF
position and close electrical disconnect to heat
pump.
Heat Anticipator Settings for Room Thermostat
(HH07AT071) — Set anticipator settings for room
thermostat according to Table 5. These settings
may be changed slightly to provide a greater degree
of comfort for a particular installation.
Table 5 — Thermostat Anticipator Settings
UNIT
38CQ
FIRST-
STAGE
ANTICIPATOR
SETTING
INDOOR
UNIT WITH
ELECTRIC
HEATER
HTR
KW
second -
stage
ANTICIPATOR
SETTINGS
015
020
027
033
40AQ Fan-Coil
with 40AQ Htrs
5 0
7 5
10 0
15 0
16
039
044
Fixed
40FS/28MQ
with 40FQ
20 0
25 0
33
048
Htrs
30 0
34 0
49
Accessory Outdoor Thermostat provides adjustable
outdoor control of accessory electric heater. This
thermostat makes contact when a drop in outdoor
temperature occurs. It energizes a stage of electric
heat when the outdoor temperature setting is
reached, provided the room thermostat is on the
second stage of heating. One outdoor thermostat is
recommended for each stage of electric heat after
the first stage. Set the outdoor thermostat(s)
progressively lower for each stage. Refer to heat
load of building and unit capacity to determine the
correct outdoor thermostat settings.
The accessory emergency heat relay is required
when 2 outdoor thermostats are used. It is auto­
matically energized by the manually operated
emergency heat switch in the indoor thermostat
subbase. The thermostat locks out compressor and
the relay bypasses the outdoor thermostats for
electric heater operation during heat pump shut­
down. When one outdoor thermostat is used, an
emergency heat relay is not required. The emer­
gency heat switch in the indoor thermostat subbase
bypasses outdoor thermostat, locks out compressor
and activates electric heater. See 40FS Indoor Unit
and Electric Heater Installation, Start-Up and
Service Instructions for installation of emergency
heat relay.
Accessory Outdoor Thermostat(s) Installation —
Install outdoor thermostat at a suitable location on
the outside of the control box. Use any free hole
to fasten thermostat bracket. Be sure that engage­
ment screw does not interfere with wiring or
components inside of control box Thermostat
bracket may be secured with only one screw;
however, make sure that bracket is firmly attached
to resist vibration forces. If a free hole is not
available, drill hole in control box after assuring
that drilling will not damage any components
inside of box If a second thermostat is used,
follow the procedure outlined above. If there is no
available space on the control box for a second
thermostat, mount the 2 thermostats together.
Connect the 2 thermostats with a machine screw,
lock washer and nut, and then mount assembled
thermostats to the control box (See Fig. 8a).
Route the capillary and attached bulb below the
control box to the upper portion of the outdoor
coil grille. Carefully insert the bulb between the
tube sheet and nearest vertical grille wire. Place the
bulb across the grille and fasten with wire, wire ties
or other suitable fastener (See Fig. 8b). Never
expose bulb to direct sunlight. If necessary, shield
bulb with appropriate material.
Replace access wrapper on unit. Check that
capillary is not pinched by wrapper
To Start Unit — (Make sure crankcase heater has
been energized for 24 hours.) Adjust the thermo­
stat as follows:
1. Set selector switch at OFF.
2. Turn on main disconnect switch(es) to indoor
and outdoor units.
3. Set fan switch as desired (ON or AUTO.).
4. Set thermostat dial at desired temperature.
5. Set selector switch at HEAT or COOL.
Check system refrigerant charge. See Refrig­
erant Charging.
SERVICE
Refrigerant Charging — The 38CQ units contain
correct operating charge for complete system when
connected to 40FS/28MQ or 40AQ indoor units
with 25 ft of tubing of recommended diameter.
Charge adjustment is required on other systems.
Adjust system charge for refrigerant line lengths
and diameters that differ from 25 ft and 3/8-in.
V