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|nstaI|er's
Guide
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. 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.
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 pressure
tap cap finger tight, then tighten
an
additional
1/6 turn. See Figure 4.
If refrigerant
lines are longer than
15 f_et and/or
a difi_rent
size than recommended,
it will be necessary
to adjust
system
refrigerant
charge upon completion
of installation.
See unit
Service Facts.
E. ELECTRICAL
CONNECTIONS
When installing or servicing this equipment, ALWAYS
exercise basic safety precautions 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
transmission
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 Control Wiring
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 5.)
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.)
4.
LOW_FAN
= Low speed Fan test mode (Short
TEST_COMMON
to this pin to force the outdoor
fan to
low speed. When the short is removed,
the fan will go
to high speed for approximately
15 seconds
and then
return
to the speed
it was running
before
the short
was applied.)
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.
24 VOLTS
WIRE SIZE
MAX. WIRE LENGTH
18 AWG
150 FT
16 AWG
225 FT.
14 AWG
300 FT.
7. Table i 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 instruc-
tion included
with the thermostat.
Wire per appropriate
hook-up diagram
(included
in these instructions).
F. DEFROST CONTROL
The demand
defrost control measures
heat pump outdoor
ambient
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 measurement.
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
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 THERMO-
STAT 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 until power has been applied
for
one (1) hour. Following
this procedure
-will prevent
potential
compressor
overload
trip at the initial start-up.
@
PiN iDENTiFiCATiON
z
0
0
o
I
k-
)m
LOW
FAN
4
18-BC55D 1-2
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