5
STEP 7
—
Check Defrost Thermostat
Check defrost thermostat to ensure it is properly located and
securely attached. There is a liquid header with a brass distributor
and feeder tube going into outdoor coil. At the end of the one of
the feeder tubes, there is a 3/8 in. O.D. stub tube approximately 2
in. long. (See Fig. 6.) The defrost thermostat should be located on
stub tube. Note that there is only one stub tube used with liquid
header, and on most units it is the bottom circuit.
FEEDER TUBE
DEFROST
THERMOSTAT
STUB TUBE
A97517
Fig. 6
---
Defrost Thermostat Location
STEP 8
—
Make Piping Connections
!
WARNING
PERSONAL INJURY AND UNIT DAMAGE
HAZARD
Failure to follow this warning could result in personal
injury or death.
Relieve pressure and recover all refrigerant before
system repair or final unit disposal.
Use all service ports and open all flow--control
devices, including solenoid valves.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
If ANY refrigerant tubing is buried, provide a 6--in. vertical
rise at service valve.
Refrigerant tubing lengths up to 36--in. may be buried
without further special consideration. Do not bury lines
longer than 36 in.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
To prevent damage to unit or service valves, observe the
following:
S
Use a brazing shield
S
Wrap service valves with wet cloth or use a heat sink
material.
Outdoor units may be connected to indoor section using
accessory tubing package or field--supplied refrigerant grade
tubing of correct size and condition. For tubing requirements
beyond 80 ft., substantial capacity and performance losses can
occur. Following the recommendations in the Long Line
Guideline for Split--System Air Conditioners and Heat Pumps
will reduce these losses. Refer to Table 1 for accessory
requirements. Refer to Table 2 for field tubing diameters.
If refrigerant tubes or indoor coil are exposed to atmosphere, they
must be evacuated to 500 microns to eliminate contamination and
moisture in the system.
Table 1—Accessory Usage
Accessory
REQUIRED FOR LOW---AMBI-
ENT APPLICATIONS
(Below 55
°
F
)
REQUIRED FOR LONG LINE
APPLICATIONS* (Over 80 ft.)
REQUIRED FOR SEA
COAST APPLICATIONS
(Within 2 miles)
Crankcase Heater
Yes
Yes
No
Evaporator Freeze Thermostat
Yes
No
No
Winter Start Control
Yes
No
No
Accumulator
No
No
No
Compressor Start Assist Capacitor
and Relay
Yes
Yes
No
Motor Master
®
Control
Yes
{
No
No
Support Feet
Recommended
No
Recommended
Liquid Line Solenoid Valve
No
See Long---Line Application
Guideline
No
Ball Bearing Fan Motor
Yes
}
No
No
* For Tubing Set lengths between 80 and 200 ft. horizontal or 20 ft. vertical differential (250 ft. Total Equivalent Length), refer to the Long Line Guidelines for Air
Conditioners and Heat Pumps using R---22.
{
Required for low---ambient controller (full modulation feature) and Motor Master
control only.
25H
C
A