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Maintenance
Inspect Regularly
Under average conditions, it is recommended that unit
heaters be inspected before every heating season - more
often in locations where air is contaminated with cor-
rosive fumes, dust, soot or oil spray. Check for dirty,
clogged coils, excessive vibration and loose connections.
Motors
A. Cleaning
Remove grease and dirt on motor during each
inspection or lubrication. Open frame motors should
be blown clean every heating season, or whenever
coils are cleaned, whichever is sooner.
B. Lubrication
1. Lubricate motor according to manufacturer’s
instructions located on the motor.
2. When no motor oiling instructions are on the
motor, oil the motor every two thousand hours
of operation with SAE20 motor oil for units in
normal applications. Adjust oiling according to
usage and atmosphere.
3. Some motors do not have oil fittings. These
motors are lubricated for long life and do not
require further lubrication.
C. Overload Protection
A change in line voltage higher or lower than motor
nameplate rating may cause overheating and serious
motor damage. Check plant voltage conditions. A
separate manual starter with thermal overload
protection device is recommended for those units
that do not have motors with built-in overload
protection.
Coils
A. Cleaning
Clean coil at least once a year; more often under
unfavorable conditions. Unless coil is kept reason-
ably free of dirt, lint and grease, its original heat-
ing capacity will be reduced - possibly to a serious
degree - and motor damage may result.
Two commonly used cleaning methods are:
1. Loosen dirt by brushing fins on side where air
enters coil and then turn on fan to blow dirt from
unit.
2. Use high pressure air hose to loosen dirt by
blowing from side where air leaves coil (side
adjacent to louvers on blow-through units; side
adjacent to fan on draw-through units).
For thorough cleaning of coil, remove motor and
fan and spray a mild alkaline cleaning solution
over the coil.
After a few minutes, follow by a hot water rinse.
(A steam gun can be used for spraying cleaning
solution and hot water.)
Coils subjected to corrosive fumes should be
checked and cleaned frequently.
B. Internal Corrosion Safeguards
1. Provide controlled water treatment - don’t use
excess of boiler compounds. Contact your boiler
compound supplier for proper usage or the
services of a water treatment laboratory.
2. Periodic internal flushing of the coils is
recommended in areas where water supply is
suspected of causing scale. Use an alka-
line-cleaning solution and introduce it at
the main pump of the hydronic system.
Flush thoroughly.
3. De-aerate boiler feed-water (particularly if large
amount of new water is used).
4. Insure rapid continuous and adequate condensate
drainage by properly sized and installed traps
and piping. Check traps for sticking.
Clean strainers ahead of traps. (When traps don’t
work, condensate accumulates in unit heater coil;
water hammer results.)
5. Adequately vent each unit.
6. Use low pressure steam when possible.
Casings
A. Cleaning
Periodic cleaning of casings is recommended to
remove dirt, grease and corrosive substances that
may injure finish. Rusted or corroded spots should be
cleaned and repainted.
B. General Inspection
Tighten fan guard and motor bracket. Check fan for
proper clearance, free rotation and firm connection to
shaft. When servicing is complete, tag unit to
indicate date of inspection, lubrication and cleaning.
WARNING
Using inorganic or mineral acids such as muriatic
(hydrochloric) acid, even though inhibited, may lead to
severe damage including corrosion and leakage
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