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NO 230V ATCOMPRESSOR
If thecompressor
voltage is notsensed when thecnmpressor
should bestarting, the contactor
may bestuck o pen o rthere i sa
wiring error. T he control willflash the appropriate
fault c ode.
Check the contactor
and control box wiring.
TROUBLESHOOTING
UNITFORPROPER SWITCHING
BETWEEN
LOW &HIGH STAGES
Check t hesuction pressures
attheservice valves. Suction
pressure
should bereduced
by3-10% when s witching from low
tohigh capacity.
NOTE: The liquid pressures
are very similar between lowand
high stage operation,
soliquid pressure
should n ot b eused f or
troubleshooting.
Compressor
current should i ncrease 20-45% when switching
fromlowto highstage. Thecompressor
solenoid, when
energized
inhigh stage, should measure
24vac.
COMPRESSOR
INTERNAL
RELIEF
The compressor
isprotected
byaninternal pressure
relief (IPR)
which relieves d ischarge gasinto compressor
shell w hen
differential
between
suction and discharge
pressures
exceeds 550
- 625psi.Thecnmpressor
is also protected by aninternal
overload
attached
tomotor windings.
TEMPERATURE
THERMISTORS
Thermistors
are electronic
devices which sense temperature.
As
thetemperature
increases,
the resistance
decreases.
Thermistors
are used t osense outdoor ambient (OAT) and coiltemperature
(OCT). Refer toFig. 2 0forresistance
values versus temperature.
See F ig. 2 5forOCT location.
If the outdoor ambient orcoil t hermistor
should fail.the HP/AC
control willflash the appropriate
fault code ( See Table 3).
IMPORTANT:
(;oilthermistor
is factory m ounted. Check t o
insure t hermistor is mounted properly. Outdoor airthermistor
(OAT) isfield mounted and connected.
Verify t hat t he OAT has
been p roperly installed.
THERMISTOR
CURVE
90 |
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".,--'------'----'------1-------'
....
,,.__.'______'____'______'______'
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Xt
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O
20
40
60
80
100
120
TEMPERATURE
(DEG.
F)
A9143t
Fig. 20 - Resistance
Values
Versus
Temperature
THERMISTOR
SENSOR
COMPARISON
The control continuously
monitors
and compares
the outdoor
air
temperature
sensor and outdoor
coil temperature
sensor to ensure
proper operating
conditions.
The comparison
is:
•
If the outdoor
air sensor indicates
->10 °F warmer than the
coil sensor
(or) the outdoor
air sensor indicates
-> 20°F
cooler
than the coil sensor, the sensors
are out of range.
If the
sensors
are
out
of range,
the
control
will
flash
the
appropriate
fault code as shown
in Table 3.
The thermistor
comparison
is not performed
during
low ambient
cooling
operation.
FAILED
THERMISTOR
DEFAULT
OPERATION
Factory
defaults
have
been
provided
in the event
of failure
of
outdoor
air thermistor
and/or coil thermistor.
If the OAT sensor
should
fail, low ambient
cooling
will not be
allowed
and the one-minute
outdoor
fan off delay will not occur.
If the OCT sensor
should
fail. low ambient
cnoling
will not be
allowed.
Refer
to the
Troubleshooting
(;hart
(Table
8) for additional
troubleshooting
information.
F
A06311
Fig.
21 - Outdoor
(?oil
Thermistor
(OCT)
Attachment
FINAL CHECKS
IMPORTANT:
Before leaving
job, be sure to do the following:
1. Ensure
that all wiring
is routed
away
from
tubing
and
sheet
metal
edges
to
prevent
rub-through
or
wire
pinching.
2. Ensure
that all wiring
and tubing
is secure
in unit before
adding
panels
and covers.
Securely
fasten
all panels
and
covers.
3. Tighten
service
valve
stem caps
to 1/2-turn
past finger
tight.
4. Leave
Users
Manual
with
owner.
Explain
system
operation
and periodic
maintenance
requirements
outlined
in manual.
5. Fill out Dealer Installation
Checklist
and place in customer
file.
(:ARE
AND MAINTENANCE
For
continuing
high
performance
and
to
minimize
possible
equipment
failure,
periodic
maintenance
must
be performed
on
this equipment.
Frequency
of maintenance
may vary depending
upon geographic
areas,
such
as
coastal
applications.
See
Users
Manual
for
information.
24
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