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Observation
Fan Motor Rocks Back And
Forth
Fan Motor(s) Don't
Operate
Fan Motor(s) Turn Slow
Motor / Fan Assembly
Noisy
Do not attempt to remove / replace fan blade in the field! Blade & motor must be replaced as an assembly.
Observation
Visible deterioration of the
coil fins. Flakes of aluminum
or white powder present in
drain pan, on product or
elsewhere in the room
Pin hole leaks in copper
tubes / return bends or
factory braze joints
If the source of the corrosion cannot be identified and / or effectively eliminated from the immediate area of the unit installation then a
replacement unit with a coated coil assembly is highly recommended. Depending upon the concentration of the corrosive agent and
level of exposure it is possible to experience premature failure of the coil surface within a very short period of time after installation.
(even if the coil has been coated). Regardless of the time frame between exposure and failure any coil which has failed due to expo-
sure to environmental corrosion is considered to be outside the product warranty coverage.
SERVICE — MAINTENANCE
TROUBLESHOOTING EC MOTOR AND FAN ASSEMBLY
Possible Cause
Normal pre-start alignment for EC motor
No power to unit
(check voltage at power term block)
Bad connection at motor lead plug or terminal
block
Obstruction blocking fan blade
Fan delay control open on electric defrost unit
Motor physically locked up
Motor windings shorted, open or burned.
Low Voltage
Jumper wire installed between lead wires 1 & 3
(low speed)
Coil fouled with frost / ice / dirt
Product stacked too close to coil face
Fan hitting obstruction / damaged
or out of balance blade
Motor bearings worn or damaged
Damaged / broken motor mount
See illustrations on page 26
TROUBLESHOOTING CORROSION OF THE COIL ASSEMBLY
Possible Cause
Wrong cleaning agent or too high of concentra-
tion of cleaner being used. Inadequate / im-
proper rinsing of cleaner from the coil surface
Corrosive agent present in air attacking
aluminum fins
Corrosive agent present in air attacking the
copper tubing or phosphorous in braze joints
(copper may also appear discolored -
possibly black or green)
Check breaker or incoming power from defrost timer
Repair / replace burned, damaged or
Clear obstruction to ensure blade / motor turns freely
Temporarily jump out or replace defective control
If blade is free but motor will not turn replace assy.
Check resistance of all (3) motor lead wires to ground
Check resistance between motor lead wires
2 & 1 (Com & High) and 2 & 3 (Com & Low)
Replace motor / fan assembly
Check voltage at motor leads. Must be +/- 10% of
Clear / clean coil of all frost / ice build-up / dirt
Relocate product to clear return air path to coil
Rotate motor / fan assembly by hand.
Clear obstructions or replace fan / motor assy.
Replace defective motor / fan assembly
Replace damaged / broken motor mount
Use correct cleaner for the application. Follow the manu-
facturers directions completely. Use copious amounts of
Identify the source of corrosion. Some potential sources
include; vinegar based salad dressings (acetic acid) and
various spices often found in prepared foods, sulfur
(from water / melting ice, forklift charging stations), prod-
ucts of combustion present in automobile exhaust (un-
trapped drain lines near drive throughs / driveways),
exhaust from fork lifts, cooking areas / vent hoods,
sewer gas from drains / vents, etc.
Similar scenario to the above - attempt to identify the
potential source of the corrosive agent. Some possible
sources include; chlorine or ammonia (present in many
commercial cleaners), urine, sulfur (from water / melting
ice), dairy products (lactic acid), bread or bread dough
(active yeast), ethylene gas (ripening fruits), acids in
dried sausage / pepperoni, etc.
24
Corrective Action
Not Applicable
loose connections
Control closes at +25° F.
unit nameplate
Remove jumper wire
Corrective Action
rinse water
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