York DM 078 manual Gas Heating Section If Equipped, Electric Heating Section If Equipped

Refrigerant Circuit and Refrigerant Safety Components shall include:

A.Independent fixed-orifice or thermally operated expan- sion devices.

B.Solid core filter drier/strainer to eliminate any moisture or foreign matter.

C.Accessible service gage connections on both suction and discharge lines to charge, evacuate, and measure refrigerant pressure during any necessary servicing or troubleshooting, without losing charge.

D.The unit shall have two independent refrigerant circuits, equally split in 50% capacity increments.

Unit Controls:

A.Unit shall be complete with self-contained low-voltage control circuit protected by a resettable circuit breaker on the 24-volt transformer side.

B.Unit shall incorporate a lockout circuit which provides reset capability at the space thermostat or base unit should any of the following standard safety devices trip and shut off compressor:

C.Loss-of-charge/Low-pressure switch.

(1)High-pressure switch.

(2)Freeze-protection thermostat, evaporator coil. If any of the above safety devices trip, an LED (light-emitting diode) indicator shall flash a diagnostic code that indi- cates which safety switch has tripped.

D.Unit shall incorporate “AUTO RESET” compressor over temperature, over current protection.

E.Unit shall operate with conventional thermostat designs and have a low voltage terminal strip for easy hook-up.

F.Unit control board shall have on-board diagnostics and fault code display.

G.Standard controls shall include anti-short cycle and low voltage protection, and permit cooling operation down to 0 ºF.

H.Control board shall monitor each refrigerant safety switch independently.

I.Control board shall retain last 5 fault codes in non-vola- tile memory, which will not be lost in the event of a power loss.

GAS HEATING SECTION (IF EQUIPPED)

Heat exchanger and exhaust system shall be constructed of aluminized steel and shall be designed with induced draft combustion with post purge logic, energy saving direct spark ignition, and redundant main gas valve. The heat exchanger shall be of the tubular type, constructed of T1-40 aluminized steel for corrosion resistance and allowing minimum mixed air entering temperature of 40 ºF. Burners shall be of the in-

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shot type, constructed of aluminum-coated steel. All gas pip- ing shall enter the unit cabinet at a single location, through either the side or bottom, without any field modifications. An integrated control board shall provide timed control of evapo- rator fan functioning and burner ignition. Heating section shall be provided with the following minimum protection:

A.Primary and auxiliary high-temperature limit switches.

B.Induced draft pressure sensor.

C.Flame roll out switch (manual reset).

D.Flame proving controls. Unit shall have two independent stages of capacity (60% 1st stage, 100% 2nd stage).

ELECTRIC HEATING SECTION (IF EQUIPPED)

An electric heating section, with nickel chromium elements, shall be provided in a range of 9 thru 54 KW, offering two states of capacity all sizes. The heating section shall have a primary limit control(s) (automatic reset) to prevent the heat- ing element system from operating at an excessive tempera- ture. The Heating Section assembly shall slide out of the unit for easy maintenance and service. Units with Electric Heating Sections shall be wired for a single point power supply with branch circuit fusing (where required).

UNIT OPERATING CHARACTERISTICS

Unit shall be capable of starting and running at 125 ºF out- door temperature, exceeding maximum load criteria of ARI Standard 340/360. The compressor, with standard controls, shall be capable of operation down to 0 ºF outdoor tempera- ture. Unit shall be provided with fan time delay to prevent cold air delivery before heat exchanger warms up. (Gas heat only)

ELECTRICAL REQUIREMENTS - All unit power wiring shall enter unit cabinet at a single factory provided location and be capable of side or bottom entry to minimize roof penetrations and avoid unit field modifications. Separate side and bottom openings shall be provided for the control wiring.

STANDARD LIMITED WARRANTIES - Compressor – 5 Years, Heat Exchanger – 10 Years, Elect. Heat Elem. – 5 Years, Parts – 1 Year

FACTORY INSTALLED OPTIONAL OUTDOOR AIR (Shall be made available by either/or):

1.ELECTRONIC ENTHALPY AUTOMATIC ECONO- MIZER – Outdoor and return air dampers that are inter- locked and positioned by a fully-modulating, spring- return damper actuator. The maximum leakage rate for the outdoor air intake dampers shall not exceed 2% when dampers are fully closed and operating against a pressure differential of 0.5 IWG. A unit-mounted potenti- ometer shall be provided to adjust the outdoor and return air damper assembly to take in outdoor air to meet the minimum ventilation requirement of the conditioned space during normal operation. During economizer oper- ation, a mixed-air temperature control shall modulate the

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