Fan Coils
INSTALLATION, OPERATION, & MAINTENANCE MANUAL
13
SECTION THREE – Normal Operation & Periodic Maintenance, Cont'd.
Motor/Blower Assembly
The type of fan operation is determined by the control
components and their method of wiring. This may vary
from unit to unit. Refer to the wiring diagram that is
attached to each unit for that unit’s individual operating
characteristics.
All motors have permanently lubricated bearings. No field
lubrication is required.
Should the assembly require more extensive service, the
motor/blower assembly may be removed from the unit
to facilitate such operations as motor or blower wheel/
housing replacement, etc.
Dirt and dust 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 taking
care not to dislodge the factory balancing weights on the
blower wheel blades.
Coil
Coils may be cleaned by removing the motor/blower
assemblies and brushing the entering air face between
fins with a stiff brush. Brushing should be followed by
cleaning with a vacuum cleaner. If a compressed air source
is available, the coil may also be cleaned by blowing 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 regularly, will require
less frequent coil cleaning.
Electric Resistance Heater Assembly
Electric resistance heaters typically require no normal
periodic 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 operating conditions for an electric
heater are proper air flow and proper supply voltage. High
supply voltage and/or poorly distributed or insufficient air
flow over the element will result in element overheating.
This condition may result in the heater cycling on the high
limit thermal cutout. Sheath heaters have automatic reset
switches only. Open-strip heaters have an automatic reset
switch with a back-up, high-limit thermal switch.
Automatic reset switches are as the name implies, they
reset automatically after the heater has cooled down.
High-limit thermal switches must be replaced once the
circuit has been broken. The high-limit thermal cutout
device is a safety 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 air flow 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 cut-out device, and may not
be evident until actual 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 operation. 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 authorization could result in
personnel injury or damage to the unit. This will also
