88
Evaporator Fan Belt Tension Adjustment —
To
adjust belt tension:
1. Turn off unit power.
2. Slide out fan deck to service position as shown in Evapo-
rator Fan Service and Replacement section above.
3. Loosen fan motor bolts.
4. Move motor mounting plate to adjust to proper belt ten-
sion. See Table 57. Motor adjuster bolts may be used to
tighten belts. See Fig. 38.
5. Check for proper belt alignment. Adjust if necessary.
6. Tighten motor mounting plate bolts to lock motor in
proper position.
7. Return fan deck back into operating position.
8. Restore power to unit.
Condenser-Fan Adjustment (Fig. 40)
1. Shut off unit power supply.
2. Remove condenser-fan assembly (grille, motor, motor
cover, and fan) and loosen fan hub setscrews.
3. Adjust fan height as shown in Fig. 40.
4. Tighten setscrews and replace condenser-fan assembly.
5. Turn on power to unit.
Verify Sensor Performance —
Verify that thermistor,
transducer, and switch inputs (see Tables 50-52) are reading
correctly. These values can be accessed through the Scrolling
Marquee display in the Temperatures, Pressures, and Inputs
menus. Some values will depend on configuration choices.
Refer to the Control Set Up Checklist completed for the
specific unit installation and to the configuration tables in
Appendix A.
Economizer Operation During Power Fail-
ure —
Dampers have a spring return. In event of power fail-
ure, dampers will return to fully closed position until power is
restored.
Do not manually operate damper motor.
Evacuation —
Proper evacuation of the system will re-
move noncondensables and ensure a tight, dry system before
charging. Evacuate from both high and low side ports. Never
use the system compressor as a vacuum pump. Refrigerant
tubes and indoor coil should be evacuated to 500 microns.
Always break a vacuum with dry nitrogen. The two possible
methods are the deep vacuum method and the triple evacuation
method.
DEEP VACUUM METHOD — The deep vacuum method
requires a vacuum pump capable of pulling a minimum vacu-
um of 500 microns and a vacuum gage capable of accurately
measuring this vacuum depth. The deep vacuum method is the
most positive way of assuring a system is free of air and liquid
water. (See Fig. 41.)
Table 57 — Belt Tension Adjustment
48PG
VOLTAGE
BELT TENSION (lb)
Unit Model Number Position 10
A,J
B,K
C,L
D,M
E,N
F,P
G,Q
H,R
20
230
4.8
5.1
5.6
4.5
NA
4.7
5.0
5.5
460
4.8
5.1
5.6
4.5
NA
4.7
5.0
5.5
575
5.3
5.1
5.6
4.5
NA
5.2
5.0
5.5
24
230
4.8
5.1
5.6
4.5
NA
4.7
5.0
5.5
460
4.8
5.1
5.6
4.5
NA
4.7
5.0
5.5
575
5.3
5.1
5.6
4.5
NA
5.2
5.0
5.5
28
230
4.5
5.4
5.9
4.5
4.5
5.4
5.9
4.5
460
4.5
5.4
5.9
4.5
4.5
5.4
5.9
4.5
575
4.5
5.4
5.9
4.5
4.5
5.4
5.9
4.5
50PG
VOLTAGE
BELT TENSION (lb)
Unit Model Number Position 10
A,J
B,K
C,L
D,M
E,N
F,P
G,Q
H,R
20
230
4.8
5.1
5.6
4.5
4.8
5.1
5.6
4.5
460
4.8
5.1
5.6
4.5
4.8
5.1
5.6
4.5
575
5.3
5.1
5.6
4.5
5.3
5.1
5.6
4.5
24
230
4.8
5.1
5.6
4.5
4.8
5.1
5.6
4.5
460
4.8
5.1
5.6
4.5
4.8
5.1
5.6
4.5
575
5.3
5.1
5.6
4.5
5.3
5.1
5.6
4.5
28
230
4.5
5.4
5.9
4.5
4.5
5.4
5.9
4.5
460
4.5
5.4
5.9
4.5
4.5
5.4
5.9
4.5
575
4.5
5.4
5.9
4.5
4.5
5.4
5.9
4.5
Fig. 40 — Condenser-Fan Adjustment
a48-5711
Содержание 48PG24
Страница 68: ...68 Fig 14 Low Voltage Control Schematic 48PG20 28 Units without Humidi MiZer System a48 7627...
Страница 69: ...69 Fig 15 Low Voltage Control Schematic 48PG20 28 Units with Humidi MiZer System a48 8227...
Страница 70: ...70 Fig 16 Low Voltage Control Schematic 50PG20 28 Units without Humidi MiZer System a48 7778...
Страница 71: ...71 Fig 17 Low Voltage Control Schematic 50PG20 28 Units with Humidi MiZer System a50 8101...
Страница 72: ...72 Fig 18 Power Schematic Units without Humidi MiZer System a48 7628...
Страница 73: ...73 Fig 19 Power Schematic Units with Humidi MiZer System a48 8228...
Страница 74: ...74 Fig 20 Component Arrangement Units without Humidi MiZer System a48 8229...
Страница 75: ...75 Fig 21 Component Arrangement Units with Humidi MiZer System a48 8230...
Страница 105: ......