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Electric Resistance Heater Assembly
Electric resistance heaters typically require no normal periodic
maintenance when unit air filters are changed properly. The opera
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tion and service life may be affected by other conditions and
equipment in the system. The two most important operating con
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ditions for an electric heater are proper air flow and proper supply
voltage. High supply voltage and/or poorly distributed or insuffi
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cient air flow over the element will result in element overheating.
This condition may result in the heater cycling on the high-limit
thermal cutout. The high-limit thermal cutout device is a safety de
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vice only and is not intended for continuous operation. With prop
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er 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 cor
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rected 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 nor
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mally not be enough to trip the high-limit thermal cutout 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 compo
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nents and wiring of the unit. This may vary from unit to unit. Con
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sult 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, contractors, or re
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lays, use only the exact type, size and voltage component as fur
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nished from the factory. Any deviation without factory authoriza
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tion could result in personal injury or damage to the unit. This will
also void all factory warranties. 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 charac
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teristics of the standard controls offered by the manufacturer are
contained in other manuals.
Valves and Piping
No formal maintenance is required on the valve-package compo
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nents 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 excessive heat should also be used during
replacement.
Filters, Throwaway
The type of throwaway filter most commonly used on fan coil
units should be replaced on a regular basis. The time interval be
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tween each replacement should be established based on regular in
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spection of the filter and should be recorded in the log for each
unit. Refer to the product catalog for the recommended filter size
for each product type and size. If the replacement filters are not
purchased from the factory, the filters used should be the same
type and size as those furnished from or recommended by the fac
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tory. Pleated media or extended surface filters should not be used
since the high air pressure drops encountered with these types of
filters are not compatible with the type of fan coil unit covered in
this manual. Consult the factory for applications using filter types
other than the factory standard or optional product.
Filters, Permanent
A maintenance schedule for permanent filters should be devel
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oped in the same manner as throwaway filters.
Unlike throwaway filters, permanent filters may be cleaned and
re-installed 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. It should then be set aside on
edge to dry.
Before replacing the filter in the unit, it should be recharged with
some type of entrapment film such as “Film-Cor Recharging Oil”
The filter should be sprayed on both sides or submerged in the
film to assure complete 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.
Consult a local filter supplier for types of available cleaning solu
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tions and charging films.
NOTE: Permanent filters normally have less static pressure loss
than throwaway filters.
Drain
The drain should be checked before initial start-up and at the be
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ginning of each cooling season to assure that the drain trap and ris
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er are clear. If it is clogged, steps should be taken to clear the de
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bris so that condensate will flow easily.
Periodic checks of the drain should be made during the cooling
season to maintain a free-flowing condensate.
Should the growth of algae and/or bacteria be a concern, consult
an air conditioning and refrigeration supply organization familiar
with local conditions for chemicals or other solutions available to
control these agents.
Replacement Parts
Factory replacement parts should be used wherever possible to
maintain unit performance, it’s normal operating characteristics,
and the testing agency listings.
Replacement parts may be purchased through a local Sales Repre
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sentative. Contact the local Sales Representative or the factory be
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fore attempting any unit modifications. Any modifications not au
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thorized by the factory could result in personnel injury, damage to
the unit, and could void all factory warranties.
When ordering parts, the following information must be supplied
to ensure proper part identification:
1. Complete unit model number
2. Unit serial number
3. Complete part description, including any numbers
Warranty
All equipment and components sold through the Parts Department
are warranted under the same conditions as the standard manufac
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turer’s warranty with the exception that the warranty period is
twelve (12) months unless the component is furnished as a war
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ranty replacement. Parts furnished as warranty replacements are
warranted for the remaining term of the original unit warranty or
not less than thirty (30) days.
