PAGE 4
Pub. No. 11-BC14D1-2
INSTALLER'S GUIDE
24 VOLTS
WIRE SIZE
MAX. WIRE LENGTH
18 AWG
150 FT
16 AWG
225 FT.
14 AWG
300 FT.
service valve. A 1/4" Open End or Adjustable wrench is required to
open gas line valve. A 3/4" Open End wrench is required to take off
the valve stem cap.
9. The liquid line shut-off valve can now be opened. Remove shut-
off valve cap. Fully insert hex wrench into the stem and back out
counterclockwise until valve stem just touches rolled edge (ap-
proximately five [5] turns) observing
WARNING
statement on
page 2. See Figure 3.
10. Replace liquid service pressure tap port cap and valve stem
cap. These caps
MUST BE REPLACED
to prevent leaks.
Replace valve stem and pressure tap cap finger tight, then
tighten an additional 1/6 turn.
11. The gas valve can now be opened. For a ball type gas valve,
open the gas valve by removing the shut-off valve cap and turning
the valve stem 1/4 turn counterclockwise, using 1/4" Open End or
Adjustable wrench. See Figure 4. For brass gas line service valve
opening, follow 9 and 10 above. See Figure 5.
12. The gas valve is now open for refrigerant flow. Replace valve
stem cap to prevent leaks. Again, these caps
MUST BE RE-
PLACED
to prevent leaks. Replace valve stem and pressure tap
cap finger tight, then tighten an additional 1/6 turn. See Figure 4.
If refrigerant lines are longer than 15 feet and/or a different size
than recommended, it will be necessary to adjust system refriger-
ant charge upon completion of installation. See unit Service Facts.
E. ELECTRICAL CONNECTIONS
▲
WARNING:
When installing or servicing
this equipment, ALWAYS exercise basic safety precau-
tions to avoid the possibility of electric shock.
1. Power wiring and grounding of equipment must comply with
local codes.
2. Power supply must agree with equipment nameplate.
3. Install a separate disconnect switch at the outdoor unit.
4. Ground the outdoor unit per local code requirements.
5. Provide flexible electrical conduit whenever vibration trans-
mission may create a noise problem within the structure.
6. The use of color coded low voltage wire is recommended to
simplify connections between the outdoor unit, the thermostat
coil temperature. The difference between the ambient and the
colder coil temperature is the difference or delta-T measurement.
This delta-T measurement is representative of the operating
state and relative capacity of the heat pump system. By measur-
ing the change in delta-T, we can determine the need for defrost.
The coil sensor also serves to sense outdoor coil temperature for
termination of the defrost cycle.
FAULT IDENTIFICATION
A fault condition is indicated by the flashing light on the defrost
control inside the heat pump control box.
In normal operation, the defrost control light will flash once each
second. If the light is flashing more than once per second or not
at all, refer to the service manual for that unit.
PIN IDENTIFICATION
(See Figure 6)
1. TEST_COMMON (Shorting any of the other pins to this pin
causes the function of the other pin to be executed. Leaving this
pin open results in the normal mode of operation.)
2. TST = Test (Shorting TEST_COMMON to this pin speeds up
all defrost board timings.)
FRC_DFT
TEST_COMMON
TST
LOW_FAN
PIN IDENTIFICATION
6
(
*
applicable to 2A6H4 Models only)
*
and the indoor unit.
Table 1 — NEC Class II Wiring
7. Table 1 defines maximum
total
length of low voltage wiring
from outdoor unit, to indoor unit, and to thermostat.
8. Mount the indoor thermostat in accordance with instruction
included with the thermostat. Wire per appropriate hookup
diagram (included in these instructions).
F. DEFROST CONTROL
The demand defrost control measures heat pump outdoor ambi-
ent temperature with a sensor located outside the outdoor coil. A
second sensor located on the outdoor coil is used to measure the
3. FRC_DFT = Forced Defrost (Short TEST_COMMON to this
pin for two [2] seconds to initiate a forced defrost. Remove the
short after defrost initiates.)
DEFROST CONTROL CHECKOUT
Normal operation requires:
a
LED on board flashing 1 time/second.
b. 24V AC between R & B
c. 24V AC between Y & B with unit operating
d. Defrost initiation when FRC_DFT pin is shorted to
TEST_COMMON pin.
If a defrost control problem is suspected, refer to the service
information in control box.
▲
WARNING:
Do NOT connect 24 VAC to T1
(ODS-A) terminal. ODS-A thermistor WILL BE BLOWN.
G. COMPRESSOR START-UP
After all electrical wiring is complete, SET THE THERMOSTAT
SYSTEM SWITCH IN THE OFF POSITION SO COMPRESSOR
WILL NOT RUN, and apply power by closing the system main
disconnect switch. This will activate the compressor sump heat
(where used). Do not change the Thermostat System Switch
