Table of Contents
Advertisement
X. OUTDOOR-COIL TEMPERATURE THERMISTOR (OCT TH)
Thermistor is for use only with duct-free split systems em-
ploying a microprocessor control (619B and 619C fan coil units
only) as part of the system diagnostics. Refer to separate in-
stallation instructions for the 619B and 619C indoor units.
The thermistor is mounted in a well attached to the con-
denser coil. See Table 6 for thermistor characteristics.
NOTE: The 619F in-ceiling fan coil units use 24-v electro-
mechanical controls for system diagnostics. Refer to 619F in-
stallation instructions for more details.
Table 6 — Thermistor Characteristics
TEMP (F)
MIN
20
36,230
30
28,330
32
26,870
40
22,320
50
17,710
60
14,230
70
11,490
77
9,900
80
9,340
90
7,610
100
6,230
110
5,130
120
4,250
130
3,550
140
2,960
150
2,500
160
2,120
170
1,810
180
1,540
190
1,320
200
1,140
210
980
212
954
220
853
230
742
NOTES:
1. A high quality digital volt-ohmmeter is required to check thermistor resistance.
2. Measure temperature at thermistor location with an accurate thermocouple-
type temperature measuring instrument.
3. If a more accurate check is required, thermistor must be removed and checked
at a known temperature (freezing point or boiling point of water).
XI. LOW-AMBIENT CONTROL THERMISTOR (LAT)
The low-ambient control thermistor is located on the outdoor
fan support bracket. See Operating Sequence section on
page 13 and Fig. 12 for more information about the controls.
XII. PRESSURE TRANSDUCER
The pressure transducer activates the low-ambient control when
discharge pressure drops to either 250 psig or 200 psig based
on the setting of control jumper J1. See Operating Sequence
section on page 13 for more information about the controls.
If transducer has to be removed for any reason, first discon-
nect the snap lock plug. The transducer can now be un-
screwed and removed without loss of refrigerant since there
is a Schrader-type core valve in the transducer port. When
reinserting the transducer, reverse this procedure. Be care-
ful not to overtighten the transducer.
MAINTENANCE
WARNING: Before performing recommended main-
tenance, be sure unit main power switch is turned off.
Failure to do so may result in electric shock or injury
from rotating fan blade.
I. LUBRICATION
A. Fan-Motor Bearings
Oiling holes are provided at each end of condenser-fan motor.
Remove fan motor and lubricate motor with 32 drops (16 drops
RESISTANCE (OHM)
NOMINAL
MAX
37,100
37,980
28,930
29,540
27,430
27,990
22,740
23,160
17,990
18,280
14,420
14,620
11,630
11,760
10,000
10,100
9,440
9,540
7,700
7,800
6,320
6,410
5,220
5,310
4,340
4,420
3,620
3,690
3,030
3,100
2,560
2,620
2,170
2,230
1,850
1,900
1,580
1,630
1,360
1,400
1,170
1,210
1,020
1,050
986
1,019
882
912
769
796
per hole) of SAE-10 (Society of Automotive Engineers) non-
detergent oil at the following intervals:
• Annually when environment is very dirty, ambient tem-
perature is higher than 105 F, and average unit operating
time exceeds 15 hours a day, or
• Every 3 years when environment is reasonably clean, am-
bient temperature is less than 105 F, and unit operating
time averages 8 to 15 hours a day, or
• Every 5 years when environment is clean, ambient tem-
perature is less than 105 F, and unit operating time aver-
ages less than 8 hours a day.
B. Compressor
Compressor contains factory oil charge; replace oil when lost.
See Table 1 for oil recharge.
NOTE: Use only Cryol 150A oil in these units.
II. CLEANING COILS
Coil should be washed out with water or blown out with com-
pressed air. Note that the blow-thru design causes dirt and
debris to build up on the inside of the coils.
Clean coil annually or as required by location and outdoor
air conditions. Inspect coil monthly and clean as required. Fins
are not continuous through coil sections. Dirt and
debris may pass through first section, become trapped be-
tween the rows of fins, and restrict condenser airflow. Use a
flashlight to determine if dirt or debris has collected between
coil sections. Clean coil as follows:
1. Turn off unit power.
2. Using a garden hose or other suitable equipment, flush
coil from the outside to remove dirt. Be sure to flush all
dirt and debris from drain holes in base of unit. Fan mo-
tors are waterproof.
TROUBLESHOOTING
I. CHECKING COOLING CONTROL OPERATION
Check the system for proper control operation as follows (re-
fer to Troubleshooting Chart on page 18 for more details):
1. Check status LED at the 538S control board. A green
LED will flash on and off at one-second intervals when
the unit is ready to run. If a time delay function is ac-
tive (3 green LED flashes followed by 2 or 3 red LED
flashes), wait 2 minutes for time delay to clear.
2. At a fan coil unit remote controller, (619B or 619C units)
select AUTO fan mode, COOL system mode, and adjust
set point down until thermometer segment is fully dis-
played. Notice the snowflake display on the handset (sys-
tem mode is COOL) and the compressor run display
(demand signal is being sent to the outdoor unit). Note
that the indoor fan starts at low speed.
For 619F units, position selector switch at subbase in
each fan speed setting in sequence.
3. At the outdoor unit, check that the LED signal lamp for
the indoor fan coil unit is illuminated, that the compres-
sor and the outdoor-fan motor start and run, that the
solenoid valve for the indoor fan coil is energized, and
that refrigerant is flowing to the correct indoor unit.
4. Observe that cooling operation shuts down when con-
trol setting at the fan coil unit is satisfied (compressor
stops, outdoor fan stops, solenoid valve closes, and LED
for fan coil demand is off).
5. Observe operation of indoor fan during the off period.
The fan will be off for 3 minutes, then turn on for 1 minute
at low speed (for occupied space air temperature
sampling).
—17—
Advertisement
Table of Contents
