To Clean Coil; Check Drain; Fan Motor Bearings; Clean Fan Wheel - Carrier 42S Series Installation, Start-Up And Service Instructions Manual

To Clean Coil

1. Be sure electrical service switch is open, locked, and
tagged while working on unit.
2. Remove return-air grille access panel and brush between
coil fins with stiff wire brush. Care should be taken to
not damage coil fins. Follow-up by cleaning with vac-
uum cleaner. If coil is cleaned with air hose and nozzle,
take care not to drive dirt and dust into other compo-
nents. Blow air through the coil fins from the leaving air
face. This should again be followed by vacuuming. Units
provided with the proper type of air filters, replaced reg-
ularly, will require less frequent coil cleaning.
3. Install clean filter. Refer to Filters section.

Check Drain

Lock open and tag unit electrical service switch.
Check drain pan, drain line and trap before initial start-up and
at start of each cooling season. A standard type pipe cleaner
for 3 / -in. ID pipe can be used to ensure that pipe is clear of
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obstruction so that condensate is carried away. Check the
drain line at filter cleaning time during the cooling season. Be
sure that debris has not fallen into unit through supply-air
grille. Should the growth of algae and/or bacteria be a con-
cern, consult an air conditioning and refrigeration supply or-
ganization familiar with local conditions for chemicals or
other solutions available to control these agents.

Fan Motor Bearings

Lock open and tag unit electrical service switch.
Standard motors are permanently sealed and lubricated. No
lubrication is required unless special motors have been sup-
plied or unusual operating conditions exist.

Clean Fan Wheel

Lock open and tag unit electrical service switch.
For access to fan assembly, remove front or bottom panel.
Fan assembly may be removed from its tracks if unit has a
long conduit lead. Dirt and debris should not be allowed to
accumulate on the blower wheel or housing. This can result in
an unbalanced blower wheel condition which can damage a
blower wheel or motor. The wheel and housing may be
cleaned periodically using a vacuum cleaner and a brush, tak-
ing care not to dislodge the factory balancing weights on the
blower wheel blades.

Clean Electric Heater

Electric resistance heaters typically require no normal period-
ic maintenance when unit air filters are changed properly. The
operation and service life may be affected by other conditions
and equipment in the system. The two most important operat-
ing conditions for an electric heater are proper airflow and
proper supply voltage. High supply voltage and/or poorly dis-
tributed or insufficient airflow over the element will result in
element overheating and possible limit switch opening. This
condition may result in the heater cycling on the high-limit
thermal cutout. The high-limit thermal cutout device is a safe-
ty device only and is not intended for continuous operation.
With proper unit application and operation, the high-limit
thermal cutout will not operate. This device only operates
when a problem exists, and ANY condition that causes high-
limit cutout MUST be corrected immediately. High supply
voltage also causes excessive amperage draw and may trip
the circuit breaker or blow the fuses on the incoming power
supply.
After proper airflow and supply power are assured, regular
filter maintenance is important to provide clean air over the
heater. Dirt that is allowed to deposit on the heating element
will cause hot spots and eventual element burn through.
These hot spots will normally not be enough to trip the high-
limit thermal cutout device and may not be evident until actu-
al heater element failure.

Electrical Wiring and Controls

The electrical operation of each unit is determined by the
components and wiring of the unit. This may vary from unit
to unit. Consult the wiring diagram attached to the unit for the
actual type and number of controls provided on each unit.
The integrity of all electrical connections should be verified
at least twice during the first year of operation. Afterwards,
all controls should be inspected regularly for proper opera-
tion. Some components may experience erratic operation or
failure due to age. Wall thermostats may also become clogged
with dust and lint and should be periodically inspected and
cleaned to provide reliable operation.
When replacing any components such as fuses, contactors, or
relays, use only the exact type, size and voltage component as
furnished from the factory. Any deviation without factory au-
thorization could result in personal injury or damage to the
unit. This will also void all factory warranties. Only factory-
supplied replacement parts ensure that the warranty and agen-
cy status remain in effect. All repair work should be done in
such a manner as to maintain the equipment in compliance
with governing codes, ordinances and testing agency listings.
More specific information regarding the use and operating
characteristics of the standard controls offered by the manu-
facturer are contained in other manuals.

Valves and Piping

No formal maintenance is required on the valve-package
components most commonly used with fan coil units other
than a visual inspection for possible leaks in the course of
other normal periodic maintenance. In the event that a valve
should need replacement, the same precautions taken during
the initial installation to protect the valve package from ex-
cessive heat should also be used during replacement.

Filters

The type of throwaway filter most commonly used on fan coil
units should be replaced on a regular basis. The time interval
between each replacement should be established based on
regular filter inspection and should be recorded in the log for
each unit. Refer to product catalog for recommended filter
size for each product type and size. If the replacement filters
are not purchased from the factory, the filter used should be
of same type and size as those furnished from or recommend-
ed by the factory. Pleated media or extended surface filter
should not be used since the high air pressure drop encoun-
tered with these type of filters is not compatible with the type
of fan coil unit covered in the manual.
A maintenance schedule for permanent filters should be de-
veloped in the same manner as throwaway filters. Unlike
throwaway filters, permanent filters may be cleaned and rein-
stalled in the unit instead of being discarded when dirty. The
optional factory permanent filter may be cleaned in hot soapy
water to remove any trapped dirt, then set aside on edge to
dry.
Before replacing the filter in the unit, it should be recharged
with some type of entrapment film. The filter should be
sprayed on both sides or submerged in the film to assure com-
plete coverage. The filter should not be allowed to soak in the
film but should be immediately removed and the excess film
drained from the filter before re-installation in the unit.
NOTE: Permanent filters normally have less static pressure loss
than throwaway filters.

Drain

The drain must be checked before initial start-up and at the
beginning of each cooling season to assure that the drain trap
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