Bryant DURAPAC 558F, Installation & Service Instructions Manual

Page: 26 / 40

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As the refrigerant leaves the evaporator, the refrigerant
passes a subcooler control low-pressure switch (S-LPS1 for
circuit 1 or S-LPS2 for circuit 2) in the suction line. This low-
pressure switch will deactivate the Perfect Humidity™ pack-
age when the suction pressure reaches 60 psig. The
subcooler control low-pressure switch is an added safety
device to protect against evaporator coil freeze-up during low
ambient operation. The subcooler control low-pressure
switch will only deactivate the 3-way liquid line solenoid
valve in the Perfect Humidity circuit. The compressors will
continue to run as long as there is a call for cooling, regard-
less of the position of the subcooler control low-pressure
switch. The 3-way solenoid valve and the Perfect Humidity
package will be reactivated only when the call for cooling has
been satisfied, the subcooler control low-pressure switch has
closed above 80 psig, and a new call for cooling exists. The
crankcase heaters on the scroll compressors provide addi-
tional protection for the compressors due to the additional
refrigerant charge in the subcooler.
When the humidistat or light commercial thermidistat con-
trol is satisfied, the control cuts power to and deenergizes
the LLSVs. The refrigerant is routed back through the evap-
orators and the subcooler coils are removed from the refrig-
erant loops. When the thermostat is satisfied, C1 and C2 are
deenergized and the compressors, IFM, and OFMs shut off.
If the thermostat fan selector switch is in the ON position,
the IFM will run continuously.
SERVICE
I. CLEANING
Inspect unit interior at beginning of each heating and cooling
season and as operating conditions require. Remove unit top
panel and/or side panels for access to unit interior.
A. Evaporator Coil
Clean as required with a commercial coil cleaner.
NOTE: The 558F300 unit has a mist eliminator screen
attached to the evaporator coil to prevent condensate runoff
at high wet-bulb conditions. Check periodically and clean as
necessary.
B. Condenser Coil
Clean condenser coil annually and as required by location
and outdoor-air conditions. Inspect coil monthly — clean as
required.
C. Condensate Drain
Check and clean each year at start of cooling season.
D. Filters
Clean or replace at start of each heating and cooling season,
or more often if operating conditions require. Refer to Table 1
for type and size.
NOTE: The 558F300 unit requires industrial grade throw-
away filters capable of withstanding face velocities up to
625 fpm. Ensure that replacement filters for the 558F300
units are rated for 625 fpm.
E. Outdoor-Air Inlet Screen
Clean screens with steam or hot water and a mild detergent.
Do not use throwaway filters in place of screens.
II. LUBRICATION
A. Compressors
Each compressor is charged with the correct amount of oil at
the factory. Conventional white oil (Sontext 200LT) is used.
White oil is compatible with 3GS oil, and 3GS oil may be
used if the addition of oil is required. See compressor name-
plate for original oil charge. A complete recharge should be
four ounces less than the original oil charge. When a com-
pressor is exchanged in the field it is possible that a major
portion of the oil from the replaced compressor may still be
in the system. While this will not affect the reliability of the
replacement compressor, the extra oil will add rotor drag and
increase power usage. To remove this excess oil, an access
valve may be added to the lower portion of the suction line at
the inlet of the compressor. The compressor should then be
run for 10 minutes, shut down, and the access valve opened
until no oil flows. This should be repeated twice to make sure
the proper oil level has been achieved.
B. Fan Shaft Bearings
The bearings are of the pillow block type and have grease fit-
tings. The bearing opposite the motor end has an extended
tube line so it can be lubricated from the motor side. Lubri-
cate the bearings twice annually.
Typical lubricants are given below:
*Preferred lubricant because it contains rust and oxidation inhibitors.
C. Condenser and Evaporator-Fan Motor Bearings
The condenser and evaporator-fan motors have permanently
sealed bearings, so no field lubrication is necessary.
III. EVAPORATOR FAN PERFORMANCE ADJUSTMENT
(Fig. 33 and 34)
Fan motor pulleys are factory set for speed shown in Table 1.
To change fan speeds:
1. Shut off unit power supply.
2. Loosen nuts on the 2 carriage bolts in the motor
mounting base. Install jacking bolt and plate under
motor base (bolt and plate are shipped in installer’s
packet). See Fig. 34. Using bolt and plate, raise motor
to top of slide and remove belt. Secure motor in this
position by tightening the nuts on the carriage bolts.
3. Loosen movable-pulley flange setscrew (see Fig. 33).
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed maximum speed specified in Table 1.
See Table 7 for air quantity limits.
5. Set movable flange at nearest keyway of pulley hub
and tighten setscrew. (See Table 1 for speed change
for each full turn of pulley flange.)
6. Replace and tighten belts. See Belt Tension Adjust-
ment section on page 27.
To align fan and motor pulleys:
1. Loosen fan pulley setscrews.
2. Slide fan pulley along fan shaft.
3. Make angular alignment by loosening motor from
mounting plate.
WARNING: Before performing service or mainte-
nance operations on unit, turn off main power switch
to unit and install lockout tag on disconnect switch.
Turn off accessory heater power switch if applicable.
Electrical shock could cause personal injury.
MANUFACTURER LUBRICANT
Texaco Regal AFB-2*
Mobil Mobilplex EP No. 1
Sunoco Prestige 42
Texaco Multifak 2