9
Marvair ComPac AVHDA I&O Manual 03/2019 Rev.3
1.7 Optional Controls & Packages
Protective Coating Packages
Two corrosion protection packages are offered- one for the condenser section (the Coastal Environmental
package) and the other for the entire unit (the Coat-All Package).
The condenser protection package includes:
• Corrosion resistant fasteners
• Sealed or partially sealed condenser fan motor
• Two layer epoxy/urethane applied to all exposed internal copper and metal in the condenser section
• A protective coating on the condenser coil
The Coat-all package includes all of the above but also includes a protective coating on the evaporator
coil and the two layer epoxy/urethane on all exterior and interior components and sheet metal. (Note:
the internal sheet metal which is insulated and the internal control box are not coated).
Dirty Filter Indicator
A diaphragm type of indicator measures the air pressure on either side of the filter and when the pressure
drops below the set point, a red LED is illuminated. The set point is adjustable.
Protective Coil Coatings
Either the condenser or evaporator coil can be coated. For harsh conditions, e.g., power plants, paper
mills or sites were the unit will be exposed to salt water, the condenser coil should be coated. Note:
Cooling capacity may be reduced by up to 5% on units with coated coils.
Cabinet Color and Material
The air conditioners are available in two standard cabinet colors -the standard grey with beige as an
option. The standard cabinet’s sides, top and front panels are constructed of 16 gauge painted steel.
Contact your Marvair representative for color chips, custom colors and 316 stainless steel cabinets.
Dual Compressors With Lead/Lag Operation
Freeze Sensor On Indoor Coil
Prevents frost on the indoor coil caused by a loss of air flow or restrictive duct work.
Filter Access From Return Air Grille
Factory or field installed filter bracket allows changing and access to the filters from the return air grille.
See model ID, special option code “I”.
Reverse Air Flow Configuration
Location of Supply and Return Air Openings are reversed.
1.8 Electrical Operation
The compressor and condenser fan are energized with a contactor controlled by a 24 VAC pilot signal.
Some compressors incorporate an internal PTC crankcase heater that functions as long as primary power
is available. The heater drives liquid refrigerant from the crankcase and prevents loss of lubrication
caused by oil dilution. Power must be applied to the unit for 24 hours before starting the compressor.
The condenser (outside fan) motor is energized by the same contactor.
The indoor evaporator fan motor is controlled by the fan purge on the electronic control board.
