Carrier 38AQS012 Installation, Start-Up And Service Instructions Manual Download Page 15

Page: 15 / 28

PRE-START-UP

System Check

1. Check all air handler and other equipment auxiliary com-

ponents. If unit has field-installed accessories, be sure all
are properly installed and correctly wired. If used, airflow
switch must be properly installed. See Fig. 11.

2. Backseat (open) compressor suction and discharge

valves. Now close valves one turn to allow refrigerant
pressure to reach test gages.

3. Open liquid line service valve.
4. Check tightness of all electrical connections.
5. Compressor oil level should be visible in sight glass. Ad-

just the oil level as required. No oil should be removed
unless the crankcase heater has been energized for at least
24 hours. See Start-Up section, Preliminary Oil Charge
on page 16.

6. Be sure unit is properly leak checked, dehydrated, and

charged. See Preliminary Charge, this page.

7. Electrical power source must agree with nameplate

rating.

8. Crankcase heater must be firmly locked into compres-

sor crankcase. Be sure crankcase is warm (heater must
be on for 24 hours before starting compressor).

9. Be sure compressor floats freely on the mounting

springs and that upper flat washers can be moved with
finger pressure. See Compressor Mounting, page 5,
and Fig. 4 for loosening compressor bolts.

Leak Test and Dehydration —

Leak test the entire

refrigerant system using soap bubbles and/or an electronic leak
detector. Evacuate and dehydrate entire refrigerant system by
use of methods described in GTAC II, Module 4, System
Dehydration.

Turn on Crankcase Heater —

Turn on crankcase

heater for 24 hours before starting the unit to be sure all refrig-
erant is out of the oil. To energize crankcase heater, perform the
following steps:

1. Set the space thermostat system switch to OFF, or adjust

the temperature so there is no demand for cooling.

2. Close the field disconnect.
3. Leave the compressor circuit breaker off. The crankcase

heater is now energized.

Preliminary Charge —

Refer to GTAC II, Module 5,

Charging, Recovery, Recycling, and Reclamation for charging
methods and procedures. Charge with R-22 by the liquid
charging method (through liquid service valve) on the high
side. See approximate refrigerant charge in Table 4. Charge ac-
cording to the values in the Charging Chart, Fig. 12 and 13 on
page 16.

Thermostat Anticipator Adjustment

HEATING/COOLING THERMOSTAT (HH07AT172,
Degrees F and HH07AT162, Degrees C) — The thermostat
has an adjustable heat anticipator for both first- and second-
stage heating circuits.
SETTINGS — Set adjustment lever for first-stage anticipator
at 0.79 (left-hand side). Set adjustment lever for second-stage
anticipator (right-hand side) at 0.42.
OUTDOOR THERMOSTAT — Refer to 40RMQ accessory
heater installation instructions for details of this thermostat (if
used).

START-UP

Compressor crankcase heater must be on for 24 hours be-

fore start-up. To energize the crankcase heater, set the space
thermostat above the ambient temperature so there is no de-
mand for cooling. Close the field disconnect. Leave the com-
pressor circuit breaker off/open. The crankcase heater is now
energized.

After the heater has been on for 24 hours, the unit can be

started. If no time has elapsed since the preliminary charge step
was completed, it is unnecessary to wait the 24-hour period.

Preliminary Checks

1. Ensure that compressor service valves are backseated.
2. Verify that the compressor floats freely on its mounting

springs.

3. Check that electric power supply agrees with unit name-

plate data.

4. Verify that compressor crankcase heater is securely in

place.

5. Check that compressor crankcase heater has been on at

least 24 hours.

6. Check to see if compressor oil level is visible in the sight

glass. If oil level adjustment is required, see the following
Preliminary Oil Charge section.

7. Recheck for leaks using same procedure as previously

outlined in Pre-Start-Up section, Leak Test and Dehydra-
tion, this page.

8. If any leaks are detected, evacuate and dehydrate as pre-

viously outlined in Pre-Start-Up section, Leak Test and
Dehydration, this page.

IMPORTANT: Before beginning Pre-Start-Up or
Start-Up, review Start-Up Checklist at the back of
this book. The checklist assures proper start-up of the
system and provides a record of unit condition, appli-
cation requirements, system information, and opera-
tion at initial start-up.

Do not attempt to start the heat pump system, even
momentarily, until the following steps have been com-
pleted. Compressor damage may result.

LEGEND

NOTES:

1. Locate YEL wire between

on DB and terminal 5 of CR3

and cut.

2. Splice airflow switch (AFS) (field supplied) contact wires (field

provided) to two ends of cut YEL wire as depicted.

Fig. 11 — Field Wiring for Airflow Switch —

38AQS012,016/40RMQ

AFS —

Airflow Switch (Sail Switch)