E. P trap: An engineered P trap (condensate drain) assembly shall be provided for each unit, to
include cleanout ports, cleanout tool, vacuum break device and see-through reservoir to
permit visual verification of water or glycol solution levels.
F. Evaporator Coil: Evaporator coil shall be AHRI Certified and shall be (silver) soldered or
brazed into the compressed refrigerant system. Coil shall be constructed of copper tubing,
permanently bonded to aluminum fins and enclosed in a galvanized steel frame. If two
compressors are used as components of the MAU, then the evaporator coil shall be of
“interlaced” configuration, permitting independent operation of either compressor without
conflict with the other compressor.
G. Supply Air blower assemblies: Blower assembly shall consist of an electric motor as
specified by A / E and a belt driven blower. Assembly shall be mounted on heavy gauge
galvanized steel rails and further mounted on [1.125 inch thick neoprene vibration
isolators][spring-type vibration isolation devices (combination helical coil spring with
neoprene support cup)].
I. Control panel / connections: Makeup Air Unit shall have an electrical control center where all
high and low voltage connections are made. Control center shall be constructed to permit
single-point high voltage power supply connections. [Electric heater shall have a separate
electrical control center and separate high voltage power circuit as shown on the plans.]
J. Packaged DX System: Makeup Air Unit shall have an integral compressor(s) and evaporator
coil located within the weather-tight unit housing. Condenser coils and appurtenant
condenser fan assemblies shall be factory installed as integral subassemblies of the MAU
and mounted on the exterior of the MAU. Condenser fan motors shall be three phase, type
56 frame, Open Air Over and Shaft Up. Each condenser fan motor shall have a vented
frame, rated for continuous duty and be equipped with an automatic reset thermal protector.
Motors shall be UL Recognized and CSA Certified.The refrigerant compressor(s) shall be
[digital] hermetic scroll-type and shall be equipped with liquid line filter drier, thermal
expansion valve (TXV), manual reset high pressure and low pressure cutouts and all
appurtenant sensors, service ports and safety devices. Compressed refrigerant system shall
be fully charged with R-410A refrigerant. Each compressor shall be factory-equipped with an
electric crankcase heater to boil off liquid refrigerant from the oil. The use of an electric
crankcase heater is an essential unit-protective device in most climates. See IOM,
Subassembly Description. [Hot gas bypass shall be provided on the lead circuit to prevent
icing of the evaporator coil under low load conditions.] Hot gas bypass is not used with
digital scroll compressors.
Packaged DX Control and Diagnostics: The Packaged DX system shall be controlled by an
onboard digital controller (DDC) that indicates both owner-supplied settings and fault
conditions that may occur. The DDC shall be programmed to indicate the following faults:
Global alarm condition (active when there is at least one alarm)
Supply Air Proving alarm
Dirty Filter Alarm
Compressor Trip alarm
Compressor Locked Out alarm
Supply Air Temperature Low Limit alarm
• Sensor #1 Out of Range (outside air temperature)
• Sensor #2 Out of Range (supply air temperature)
• Sensor #3 Out of Range (cold coil leaving air temperature)
Product Specifications: Packaged Outdoor Heating and Cooling Make-Up Air Conditioners with Packaged DX (08/10) Page 4 of 7
Copyright © 2010 Greenheck Fan Corporation
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