Marvair 8AA1024A-1060A & 8AA2036A-2060A I&O Manual
03/2021 Rev.1
9
pigment) technology.
The Coat all Package includes all of the above, plus:
• Protective coating on the evaporator coil (Luvata Insitu®) contains ES2 (embedded stainless steel
pigment) technology
• Protective coating on exterior and interior components and sheet metal. (Note: the internal sheet
metal which is insulated, bottom outside panel, and the internal control box are not coated)
Hot Gas Bypass (Non-Economizer Models Only)
Used in specialty applications; i.e., Magnetic Resonance Imaging (MRI) buildings, to prevent magnetic
voltage disturbance caused by compressor cycling. Two hot gas bypass option packages are available
to allow operation to 20°F (-7°C) or minus 20°F (-29°C). Please refer to Hot Gas Bypass Application
Bulletin for details.
Electric Reheat Dehumidification
A humidity controller allows electric heat and cooling to operate simultaneously. Marvair
®
air conditioners
equipped with the dehumidification option allow the indoor humidity of the controlled environment
to be maintained at or below a certain humidity set point. These units do not have the ability to add
humidity to the building.
IMPORTANT
The electrical wire and breaker or fuses must be sized for simultaneous operation
of the electric heater and the air conditioner. Refer to the data sticker on the unit or
the appropriate Air Conditioner Product Data Sheet for the sizing information.
Dehumidification is achieved by operating mechanical cooling in conjunction with electric reheat. The
strip heat is sized approximately to the sensible capacity of the total tonnage of the machine (i.e., on a
24,000 BTU unit the strip heat is sized at approximately 20,000 BTU). Because the strip heat is sized
to the approximate sensible cooling capacity, only selected models are available.
Operation:
When the humidity rises above the set point on the humidity controller both mechanical cooling and
electric reheat operate to temper the air and lower the humidity. If the temperature in the controlled
environment rises above the set point of the thermostat and the unit is operating in the dehumidification
mode, the call for cooling will override the call for dehumidification and the strip heat is disengaged
until the thermostat is satisfied. This assures the environment temperature is maintained as first priority
and humidity control is second.
In applications where a shelter has redundant air conditioning units and is controlled by a lead lag control-
ler (CommStat Touch, CommStat 4, CommStat 3 HVAC Controller), most times the dehumidification
option is only necessary on one of the two units. It is possible for one unit to be operating in the cooling
mode while the unit with dehumidification is operating at the same time. If the cooling unit does not
maintain the shelter temperature set point, the unit with dehumidification will go into the cooling mode.
It does not matter whether the unit with dehumidification is the lead or lag unit.
Three Phase Voltage Monitor
Continuously measures the voltage of each of the three phases. The monitor separately senses low
and high voltage, voltage unbalance including phase loss and phase reversal. An LED indicator glows
when all voltages are acceptable. Automatically resets when voltages and phases are within operating
tolerances. Not required on 1ø units.
Dirty Filter Indicator
A diaphragm type of indicator measures the air pressure on either side of the filter and when the pressure
