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11. Ensure surfaces are not allowed to dry before rinsing.
Reapplying cleaner as needed to ensure 10-minute satura-
tion is achieved.
12. Thoroughly rinse all surfaces with low velocity clean wa-
ter using downward rinsing motion of water spray nozzle.
Protect fins from damage from the spray nozzle.
MICROCHANNEL HEAT EXCHANGER (MCHX) CON-
DENSER COIL MAINTENANCE AND CLEANING
RECOMMENDATIONS
Routine cleaning of coil surfaces is essential to maintain
proper operation of the unit. Elimination of contamination and
removal of harmful residues will greatly increase the life of the
coil and extend the life of the unit. The following steps should
be taken to clean MCHX condenser coils:
1. Remove any foreign objects or debris attached to the core
face or trapped within the mounting frame and brackets.
2. Put on personal protective equipment including safety
glasses and/or face shield, waterproof clothing and
gloves. It is recommended to use full coverage clothing.
3. Start high pressure water sprayer and purge any soap or
industrial cleaners from sprayer before cleaning condens-
er coils. Only clean potable water is authorized for clean-
ing condenser coils.
4. Clean condenser face by spraying the core steady and
uniformly from top to bottom while directing the spray
straight toward the core. Do not exceed 900 psig or
30 degree angle. The nozzle must be at least 12 in. from
the core face. Reduce pressure and use caution to prevent
damage to air centers.
CONDENSATE DRAIN — Check and clean each year at
start of cooling season. In winter, keep drains and traps dry.
FILTERS — Clean or replace at start of each heating and cool-
ing season, or more often if operating conditions require. Refer
to Installation Instructions for type and size.
NOTE: The unit requires industrial grade throwaway filters
capable of withstanding face velocities up to 625 fpm.
OUTDOOR-AIR INLET SCREENS — Clean screens with
steam or hot water and a mild detergent. Do not use disposable
filters in place of screens.
Lubrication
FAN SHAFT BEARINGS — Lubricate bearings at least ev-
ery 6 months with suitable bearing grease. Do not over grease.
Typical lubricants are given below:
*Preferred lubricant because it contains rust and oxidation inhibitors.
CONDENSER AND EVAPORATOR-FAN MOTOR BEAR-
INGS — The condenser and evaporator-fan motors have perma-
nently sealed bearings, so no field lubrication is necessary.
Evaporator Fan Performance Adjustment
(Fig. 40) —
Fan motor pulleys are designed for speed
shown in Physical Data table in unit Installation Instructions
(factory speed setting).
To change fan speeds, change pulleys.
To align fan and motor pulleys:
1. Shut off unit power supply.
2. Loosen fan shaft pulley bushing.
3. Slide fan pulley along fan shaft.
4. Make angular alignment by loosening motor from
mounting plate.
5. Retighten pulley.
6. Return power to the unit.
Evaporator Fan Coupling Assembly — If the cou-
pling has been removed for other blower assembly component
repair or replacement, it is critical that the coupling be reassem-
bled and aligned correctly to prevent premature failures.
REASSEMBLING THE COUPLING INTO THE UNIT
(Fig. 41)
1. Prior to reassembling the coupling, loosen the 4 bearing
mounting bolts, which secure the 2 bearings on either side
of the coupling. Remove the drive belts.
2. Reassemble the coupling with the bearings loose. This
allows the coupling to find its own self-alignment position.
3. Check the hub-to-shaft fit for close fitting clearances.
Replace hubs if high clearances are determined.
4. Check the key for close-fitted clearances on the sides and
0.015 in. clearance over the top of the key. Replace key if
necessary.
5. Be sure that hub flanges, flex members, spacer, and hard-
ware are clean and free of oil.
6. Place the flanges onto the shafts with the hub facing out-
ward. Do not tighten the set screws at this time.
CAUTION
Do not apply any chemical cleaners to MCHX condenser
coils. These cleaners can accelerate corrosion and damage
the coil.
CAUTION
Excessive water pressure will fracture the braze between
air centers and refrigerant tubes.
MANUFACTURER LUBRICANT
Texaco Regal AFB-2*
Mobil Mobilplex EP No. 1
Sunoco Prestige 42
Texaco Multifak 2
IMPORTANT: Check to ensure that the unit drive matches
the duct static pressure using Tables 3-38.
Fig. 40 — Evaporator-Fan Alignment
and Adjustment
A48-4036