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COOLING SYSTEM

The cooling section is a complete factory package utilizing an
air-cooled condenser. The system is factory-charged with
Refrigerant-22.
The compressors are hermetically sealed, internally sprung
and base mounted with rubber insulated hold-down bolts.
Compressors have inherent (internal protection. If there is an
abnormal temperature rise in compressor, the protector will
open to shut down the compressor.

PRELIMINARY OPERATION COOLING

After installation has been completed, energize the crankcase
heaters for at lest four hours before operation the unit. After the
initial installation, the compressors should be given three false
starts (energized just long enough to make a few revolutions
with 5-7 minutes delay between each start, before being put
into full time service.

COOLING SEQUENCE OF OPERATION

NO OUTDOOR AIR OPTIONS - When the room thermostat
calls for “first-stage” cooling, the low voltage control circuit from
“R” to “G” and “Y1" is completed to energize compressor #1,
condenser fan motor #1, condenser fan motor #2 (if the ambient
temperature is above 60

°

F), and the supply air blower motor (if

the fan switch on the room thermostat is set in the ”AUTO"
position).
When the thermostat calls for “second-stage” cooling, the low
voltage control circuit from “R” to “Y2" is completed to energize
compressor #2.
After the thermostat is satisfied and opens, all components will
stop simultaneously. The blower motor will continue to operate
if the fan switch on the room thermostat is set in the “ON”
position.

ECONOMIZER WITH SINGLE ENTHALPY SENSOR - When
the room thermostat calls for “first-stage” cooling, the low
voltage control circuit from “R” to “G” and “Y1" is completed.
The  ”R" to “G” circuit energizes the blower motor (if the fan
switch on the room thermostat is set in the “AUTO” position)
and drives the economizer dampers from fully closed to their
minimum position. If the enthalpy of the outdoor air is below the
setpoint of the enthalpy controller (previously determined), “Y1"
energizes the economizer. The dampers will modulate to
maintain a constant supply air temperature as monitored by the
discharge air sensor. If the outdoor air enthalpy is above the
setpoint, ”Y1" energizes compressor #1, condenser fan motor
#1, and condenser fan motor #2 (if the ambient temperature is
above 60

°

F).

When the thermostat calls for “second-stage” cooling, the low
voltage control circuit from “R” to “Y2" is completed. If the
enthalpy of the outdoor air is below the setpoint of the enthalpy
controller (i.e. first stage has energized the economizer), ”Y2"
will energize compressor #1. If the outdoor air is above the
setpoint, “Y2" will energize compressor #2.

After the thermostat is satisfied and opens, all components will
stop simultaneously. The blower motor will continue to operate
if the fan switch on the room thermostat is set in the “ON”
position.
ECONOMIZER WITH DUAL ENTHALPY SENSORS - The
operation with the dual enthalpy sensors is identical to the
single sensor except that a second enthalpy sensor is mounted
in the return air. This return air sensor allows the economizer
to choose between outdoor air and return air, whichever has
the lowest enthalpy value, to provide maximum operating
efficiency.

ECONOM IZ ER (SINGLE OR DUAL) WITH POWER
EXHAUST - This system operates as specified above with one
addition. The power exhaust motor is energized whenever the
economizer is chosen by the enthalpy sensor for first stage
cooling,  “Y1". As always, the ”R" to “G” connection provides
minimum position but does not provide power exhaust
operation.
MOTORIZED OUTDOOR AIR DAMPERS - This system
operation is the same as the units with no outdoor air options
with one exception. When the “R” to “G” circuit is complete, the
motorized damper drives open to a position set by the
thumbwheel on the damper motor. When the “R” to “G” circuit
is opened, the damper spring returns fully closed.
CONTINUOUS BLOWER - Continuous blower operation is
possible by closing the R to G circuit on the thermostat.

SAFETY CONTROLS

Each refrigerant system is equipped with the following safety
controls:

1. A Suction Line Freezestat to protect against low evaporator

temperatures due to a low air flow or a low return air
temperature. (Opens at 26

°

F +5

°

 F and resets at 38

°

F +

5

°

F.)

2. A High Pressure Cutout Switch to protect against excessive

discharge pressures due to a blocked condenser coil or a
condenser motor failure. (Opens at 380 psig + 10 and resets
at 300 psig + 10.)

3. A Low Pressure Switch to protect against loss of refrigerant

charge. (Opens at 7 psiog + 3 and resets at 22 psig +  5.)

If either one of the above safety controls opens, that individual
refrigerant system will be locked out. The other refrigerant
system will continue in operation unless it too is effected by the
same fault. The lock out of either system can be reset by
opening the 24V circuit either at the room thermostat or at the
unit disconnect.

HEATING SYSTEM

The following sequence describes the operation of the gas heat
section.
CONTINUOUS BLOWER
With the room thermostat switch set to “ON”, the supply air
blower will operate continuously. The normally closed contact
“K5-1" provides 24 volt power to the “3M” contactor. The “3M-1,
2 & 3" power contacts close and the blower motor operates.
INTERMITTENT BLOWER
With the room thermostat system switch set to the “AUTO” or
“HEAT” position and the fan switch set to “AUTO”, the supply
air blower will operate after the room thermostat calls for heat
and the time delay relay closes.
The  “TH1" closes, the heat relay ”RW1" is energized. The
“RW1-1” power contact closes energizing the line voltage draft
motor. The “RW1-2" contact is also closed. As the speed of the
draft motor reaches approximately 2500 RPM, the centrifugal
switch contact located on the end of the draft motor shaft closes
to power the first stage ignition module “IC1”.
Ignition module “IC1" will immediately start the first stage ignitor
sparking and will open the redundant valve located inside the
first stage main gas valve “GV1” to allow a flow of gas to only
the first stage carryover tube. Only after the pilot flame has been
ignited and the presence of pilot flame detected at the “IC1” by
a signal sent back through the flame sensor is sparking
terminated and the first stage main gas valve opened.
Gas flows into each of the main burners and is ignited from the
carryover tube flame.

If “IC1” fails to detect a pilot flame, it will continue to try for a
maximum of 85 seconds to ignite the pilot tube. If the pilot flame
is not detected, then “IC1" will lock out first stage furnace

OPERATION

530.18-N6Y

16

Unitary Products Group

Summary of Contents for D2CG180

Page 1: ...rsion Accessory USA 530 18 N6 2V High Altitude Accessory Nat Gas 530 18 N6 3V High Altitude Accessory Propane 530 18 N13Y Coil Guard Installation Renewal Parts Refer to the Renewal Parts Manual for co...

Page 2: ...7 Four And Six Point Loads 12 8 Supply Air Blower Perf 15 Ton 13 9 Supply Air Blower Perf 20 Ton 14 10 Static Resistances 15 11 Power Exhaust Performance 15 12 Blower Motor and Drive Data 15 13 Limit...

Page 3: ...ame other than a YORK roof curb gasketing must be applied to all surfaces that come in contact with the unit underside 5 Maintain level tolerance to 1 2 inch maximum across the entire length or width...

Page 4: ...ductwork to accommodate the damper Using the holes in the hood flanges as a template drill 9 64 inch dia 26 drill holes into the ductwork and secure with the screws provided CAUTION If outdoor air in...

Page 5: ...ing to the unit waterproof type connectors MUST BE USED so that water or moisture cannot be drawn into the unit during normal operation The above waterproofing conditions will also apply when installi...

Page 6: ...or John Crane may be used 4 All piping should be cleaned of dirt and scale by hammering on the outside of the pipe and blowing out the loose dirt and scale Before initial start up be sure that all of...

Page 7: ...securing in place OPTIONAL ECONOMIZER MOTORIZED DAMPER RAIN HOOD The instruction for the optional economizer motorized damper rain hood can be found in form 44 320 2 Use these instructions when field...

Page 8: ...FIG 9 ENTHALPY SETPOINT ADJUSTMENT 530 18 N6Y 8 Unitary Products Group...

Page 9: ...6 0 43 3 COMPRESSOR Qty Per Unit 10 TON TANDEM 1 2 5 TON HERMETIC 1 AIR FILTERS QUANTITY PER UNIT 16 X 20 X 2 4 QUANTITY PER UNIT 16 X 25 X 2 4 QUANTITY PER UNIT 18 X 24 X 2 5 TOTAL FACE AREA sq ft 15...

Page 10: ...84 9 100 460 3 60 19 2 124 9 6 62 1 2 1 5 7 2 42 4 50 575 3 60 15 4 100 7 7 50 1 2 0 5 5 9 33 9 40 DCG240 208 230 3 60 38 4 248 38 4 248 1 4 1 4 2 7 5 21 0 19 4 115 1 111 6 125 460 3 60 19 2 124 19 2...

Page 11: ...ic meters gas meters regulators and relief equip R E T U R N A I R S U P P L Y A I R B O T T O M S U P P L Y A N D R E T U R N A I R O P E N I N G S S e e N o t e B P O W E R W I R I N G E N T R Y A C...

Page 12: ...NOTE These weights are with economizer and the largest blower motor available UNIT 6 POINT LOADS LBS TOTAL A B C D E F 180 2300 351 367 392 416 399 375 240 2500 334 350 426 502 481 407 NOTE These weig...

Page 13: ...7 3 0 2 7 0 4 3 5 3 1 915 5 0 1 1 2 6 2 4 0 8 3 1 2 8 0 5 3 6 3 2 0 2 4 1 3 7 965 4 0 1 2 2 7 2 5 0 9 3 2 2 9 0 6 3 7 3 3 0 4 4 4 3 9 0 2 5 0 4 5 980 3 5 1 3 2 9 2 6 1 0 3 4 3 0 0 7 3 8 3 4 0 5 4 5 4...

Page 14: ...4 1 1 5 0 4 2 0 6 5 9 5 0 0 1 6 7 5 7 950 3 5 1 7 4 2 3 6 1 3 5 1 4 3 0 8 6 0 5 1 0 2 6 9 5 8 965 2 5 1 9 4 5 3 8 1 5 5 4 4 5 1 0 6 3 5 3 0 4 7 2 6 1 0 1 8 5 7 1 995 2 0 2 1 4 6 3 9 1 6 5 5 4 7 1 1 6...

Page 15: ...65 1190 BK80 7 75 7 4 1 BX68 69 8 1 20 TON Stan dard 870 1025 7 5 213T 89 1VP68 6 75 5 5 6 52 1 3 8 BK120 11 75 11 4 1 3 16 BX83 84 8 1 High Speed Access 950 1120 BK110 10 75 10 4 1 3 16 BX81 81 8 1 1...

Page 16: ...rating efficiency ECONOMIZER SINGLE OR DUAL WITH POWER EXHAUST This system operates as specified above with one addition The power exhaust motor is energized whenever the economizer is chosen by the e...

Page 17: ...here are two separate gas valves in the furnace Each valve contains a main and a redundant valve The redundant valves are located upstream of the main gas valves Should either or both of the main gas...

Page 18: ...units If gas pressure is outside these limits contact the local gas utility for corrective action MANIFOLD GAS PRESSURE ADJUSTMENT Small adjustments to the high fire gas flow may be made by turning th...

Page 19: ...within the limitations shown in the Applications Data Table 2 Pulleys can be adjusted in half turn increments 3 The tension on the belt should be adjusted as shown in the Belt Adjustment figure Start...

Page 20: ...2 With the furnace turned on measure the time needed for one revolution of the hand on the smallest dial on the meter A typical gas meter usually has a 1 2 or a 1 cubic foot test dial 3 Using the numb...

Page 21: ...E Exercise care when cleaning the coil so that the coil fins are not damaged Do not permit the hot condenser air discharge to be obstructed by overhanging structures of shrubs BURNER PILOT Periodicall...

Page 22: ...tat fan switch set to AUTO a Set fan switch to ON If blower motor runs go to Step f If it does not check to see if line voltage is being supplied to the contacts of the contactor M3 and if the contact...

Page 23: ...T CHECKOUT b Check all wiring between the ignitor control and the gas valve Check to make sure the ground connections are intact c If the wiring is intact check for 24 volts across terminals PV and CO...

Page 24: ...and information from OUR current parts list for this unit are available to your servicing contractor through our local distributor The name and address of our nearest distributor may be obtained by co...

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