PAGE 4
Pub. No. 11-AC17D1-1
INSTALLER'S GUIDE
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
REPLACED to prevent leaks. Replace valve stem and pres-
sure 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 page 6 and 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
and the indoor unit.
Table 1 — NEC Class II Wiring
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.)
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 24V AC to T1
(ODS-A) terminal. ODS-A thermistor WILL BE BLOWN.
G. COMPRESSOR START-UP
After all electrical wiring is complete, SET THE THERMO-
STAT SYSTEM SWITCH IN THE OFF POSITION SO COM-
PRESSOR WILL NOT RUN, and apply power by closing the
system main disconnect switch. This will activate the compres-
sor sump heat (where used). Do not change the Thermostat
System Switch until power has been applied for one (1) hour.
Following this procedure will prevent potential compressor
overload trip at the initial start-up.
FRC_DFT
TEST_COMMON
TST
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 coil temperature. The difference between the ambient and
the colder coil temperature is the difference or delta-T measure-
ment. This delta-T measurement is representative of the
operating state and relative capacity of the heat pump system.
By measuring 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.
6
PIN IDENTIFICATION
24 VOLTS
WIRE SIZE
MAX. WIRE LENGTH
18 AWG
150 FT
16 AWG
225 FT.
14 AWG
300 FT.
