York R-410A - Manual (Page 9)

251933-YTG-J-1009
Johnson Controls Unitary Products 9
factor. Units shall be designed not to operate above service
factor. Fan wheel shall be double-inlet type with forward-curved
blades, dynamically balanced to operate smoothly throughout
the entire range of operation. Airflow design shall be constant
air volume. Bearings shall be sealed and permanently
lubricated for longer life and no maintenance.
Outdoor (Condenser) Fan Assembly
The outdoor fan shall be of the direct-driven propeller type,
discharge air vertically, have aluminum blades riveted to a
corrosion resistant steel spider bracket and shall be
dynamically balanced for smooth operation. The outdoor fan
motor shall be totally enclosed with permanently lubricated
bearings, internally protected against overload conditions and
staged independently.
Refrigerant Components
Compressor:
a. Shall be internally protected with internal high-pressure
relief and over temperature protection.
b. Shall have internal spring isolation and sound muffling to
minimize vibration and noise, and be externally isolated
on a dedicated, independent mounting.
Coils:
a. Evaporator coils shall have aluminum plate fins
mechanically bonded to seamless internally enhanced
copper tubes with all joints brazed. Special Phenolic
coating shall be available as a factory option.
b. Evaporator coils shall be of the direct expansion, draw-
thru design.
c. Condenser coils shall have aluminum plate fins
mechanically bonded to seamless internally enhanced
copper tubes with all joints brazed or Micro-Channel
aluminum tube, aluminum fins.
d. Condenser coils shall be of the direct expansion, draw-
thru design.
Refrigerant Circuit and Refrigerant Safety Components shall
include:
a. Independent fixed-orifice or thermally operated
expansion devices.
b. Filter drier/strainer to eliminate any moisture or foreign
matter.
c. Accessible service gage connections on both suction
and liquid lines to charge, evacuate, and measure
refrigerant pressure during any necessary servicing or
troubleshooting, without losing charge.
d. The refrigeration system shall provide at least 15°F of
sub-cooling at design conditions.
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.
d. High-pressure switch.
e. Freeze-protection thermostat, evaporator coil.
f. Unit shall incorporate “AUTO RESET” compressor over
temperature, over current protection.
g. Unit shall operate with conventional thermostat designs
and have a low voltage terminal strip for easy hook-up.
h. Unit control board shall have on-board diagnostics and
fault code display.
i. Standard controls shall include anti-short cycle and low
voltage protection, and permit cooling operation down to
0°F.
j. Control board shall monitor each refrigerant safety switch
independently.
k. Control board shall retain last 5 fault codes in non volatile
memory which will not be lost in the event of a power loss.
Gas Heating Section (Single Or 2 Stage)
Shall be designed with induced draft combustion with post
purge logic, energy saving direct spark ignition, and redundant
main gas valve. Venter wheel shall be constructed of stainless
steel for corrosion resistance. 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 25°F. Burners shall be of the inshot type,
constructed of aluminum coated steel and contain air mixture
adjustments. All gas piping shall enter the unit cabinet at a
single location through either the side or curb without any field
modifications. Integrated control boards shall provide timed
control of evaporator 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 motor speed sensor.
c. Flame roll out switch.
d. Flame proving controls.
e. If any of the above safety devices trip, a LED (light-
emitting diode) indicator shall flash a diagnostic code that
indicates which safety switch has tripped.
NOTE: All 2 Stage Gas Heat, 60% Capacity 1
st
Stage, 40%
Capacity 2
nd
Stage.