B.Shall have internal isolation and sound muffling to minimize vibration and noise, and be externally iso- lated on a dedicated, independent mounting.
2.Coils:
A.Evaporator and condenser coils shall have alumi- num plate fins mechanically bonded to seamless
B.Evaporator and Condenser coils shall be of the direct expansion,
3.Refrigerant Circuit and Refrigerant Safety Compo- nents shall include:
A.Independent thermal expansion devices (TXV).
B.
C.Accessible service gage connections on both suc- tion and discharge lines to charge, evacuate, and measure refrigerant pressure during any necessary servicing or troubleshooting, without losing charge and without disrupting condenser or evaporator air flow.
D.The refrigeration system shall provide at least 10° F of liquid
E.Unit shall have a suction line accumulator and auto- matic reversing valve.
4.Unit Controls:
A.Unit shall contain a large, low voltage Terminal Board for easy connection of field low voltage wir- ing.
B.Controls shall be mounted in a large control box with
C.Unit shall contain a reliable demand defrost control to provide defrost. The defrost control shall also have an “X” terminal to provide a 24 volt signal for
room thermostat “LED” indication of unit lockout. Plus a built in 5 minute
D.Unit shall have large, easily removable panels, cov- ering electrical controls and compressor, allowing easy access for any maintenance or servicing.
ELECTRIC HEATING SECTION
1.An electric heating section, with nickel chromium elements, shall be provided in a range of 5 thru 25 KW.
2.The heating section shall have an automatic reset primary limit control to prevent the heating element system from operating at an excessive tempera- ture.
3.The heating section assembly shall slide out of the unit for easy maintenance and service.
4.Units with electric heating sections shall be wired for a single point power supply, with branch circuit fusing (where required).
UNIT OPERATING CHARACTERISTICS
1.Unit shall be capable of starting and running at 125° F outdoor temperature, exceeding maximum load criteria of ARI Standard 210/240.
2.The compressor, with standard controls, shall be capable of operation down to 45° F outdoor tem- perature.
ELECTRICAL REQUIREMENTS
All unit power wiring shall enter unit cabinet at a single factory provided location and be capable of side or bot- tom entry. This will minimize roof penetrations and avoid unit field modifications. Separate side and bot- tom openings shall be provided for the control wiring.
26 | Unitary Products Group |