background image

to the compressor so that eventually the oil pressure switch
opens. This requires re-setting manually at the unit.

PRE-START CHECK

Before starting the unit, the following check list should be
completed.

1. Make sure the proper clearances were considered.
2. Make sure all foreign matter has been removed from the

interior of the unit (tools, construction or shipping
materials).

3. Rotate all fans and blower wheels manually to check for free

rotation.

4. Check belt tensions and alignment.
5. Make sure all wiring connections are tight.
6. Make sure the available power supply and unit nameplate

data agree.

7. Make sure the fuse sizes and the power wire are properly

sized.

8. Make sure all controls are set at their proper set points.
9. Make sure condensate drain line is trapped per instructions

as indicated with Figure 4.

10 For shipping, the compressor hold-down nuts are

tightened, drawing the mounting feet down to the shipping
stops. After the unit is in its final position, the four hold-down
nuts must be removed to insert the rubber grommets found
in the small parts bag. Replace the hold-down nuts and
tighten until they start to compress the isolator springs and
then give them an additional half turn.

INITIAL START-UP

1. Supply power to the unit through the disconnect switch at

least 8 hours prior to starting the compressors.

2. Move the system switch on the thermostat or the status

panel to the AUTO position.

3. The proper supply air CFM should be established at this

time with an inclined manometer as outlined in this
instruction. This is an important part of the start-up

procedure since it directly affects nuisance trip-outs on unit
safety controls, condensate water blow-off from the
evaporator coil, bearing and shaft damage, noise and
vibration.

4. Lower the room thermostat to energize compressor No. 1.
5. With an ammeter, check the compressor and the supply air

blower amps to make sure they agree with the unit data
plate.

6. Lower the room thermostat to energize compressor No. 2

or load the compressor.

7. Check the compressor amps with the unit data plate.
8. After approximately 15 minutes of operation, check the

liquid line sight glasses for a proper liquid refrigerant seal
in each of the refrigerant circuit(s).

9. Next increase the setting of the room thermostat until the

heating contacts are energized.

10. Refer to the proper heating installation and operation

instruction for the correct heating sequence of operation.

11. After the unit has been operating for several minutes,

de-energize the main power and inspect all factory wiring
connections and bolted surfaces for tightness.

POST-START CHECK LIST

After the entire control circuit has been energized, check the
following:

1. Cooling system start-up.
2. Rotation of blower wheels. Adjust the air system if

necessary per the procedures as outlined in this instruction.

NOTE: If the supply air blower rotates in the wrong direction,

reverse two of the motor leads at blower motor contac-
tor 3M.

3. Operation of the outside and return air dampers as

explained under “Damper Linkage Adjustment” in this
instruction.

Code: SBY

530.25-N3Y

Unitary Products Group
P.O. Box 1592, York, Pennsylvania USA 17405-1592
Subject to change without notice.   Printed in U.S.A
Copyright 

 by York International Corporation 1994.  All Rights Reserved.

CAUTION: Prior to any of the following maintenance proce-

dures, shut off all electircal power to the unit to
prevent personal injury.

FILTERS

The filters must be replaced as often as necessary to assure
good air flow and filtering action.
Refer to Figure 1 for filter access location.

COILS

Do not allow dirt to accumulate on the evaporator and condenser
coil or other parts of the evaporator and condenser circuit. Clean
as often as necessary to assure good system performance. Use
a brush, vacuum cleaner attachment or other suitable means.

DRAIN PAN

The drain pan should be inspected regularly to assure proper
drainage.

LUBRICATION

The bearings for the blower shaft and the blower motor are
permanently lubricated and should not require any additional
lubrication.

BELTS

Maintain belt tension to extend belt life. Replace when signs of
failure begin to appear.

DSC360

DSC480

40 lbs. 8 oz.

29 lbs. 8 oz. each system

REFRIGERANT CHARGE R-22

MAINTENANCE

Summary of Contents for D*SC360

Page 1: ...te request for inspection by the carrier s agent should be made in writing Refer to Form 50 15 NM for additional information REFERENCE Additional information on the design installation operation and service of this equipment is available in the following reference forms 55 70 N1 General Installation 55 70 N2 Pre start Post start Check List Renewal Parts Refer to the Renewal Parts Manual for comple...

Page 2: ...ta 21 10 Resistances Unit Options Accessories 21 11 Supply Air Blower Performance 22 FIGURES No Description Page 1 Unit Less Panels 3 2 Typical Rigging 3 3 Center of Gravity 3 4 Recommended Drain Piping 4 5 Bottom Power Wiring Entrance 5 6 Side Power Wiring Entrance 5 7 Control Wiring Entrance DSC360 6 8 Control Wiring Entrance DSC480 6 9 Control Wiring Conns w o Status Panel 7 10 Control Wiring C...

Page 3: ... mounting curbs capable of supporting the unit s weight may also be field fabricated CLEARANCES These units must be installed with the minimum clearances listed below A 2 clearance within 3 feet of the unit must be maintained between any combustible material and the supply air duct work No objects should be left near the combustion air inlet to obstruct the openings If the unit is slab mounted shr...

Page 4: ... 90 degrees clockwise to facilitate entrance of the power wiring from the side of the box To do this remove the 1 4 bolt holding the power lug Next remove the slotted spring pin which keeps the lug from rotating Turn the power lug 90 degrees clockwise and replace both the slotted spring pin and the 1 4 bolt MODEL DSC 360 480 Voltage Variation Min Max1 200 Volts 187 218 230 Volts 216 252 460 Volts ...

Page 5: ...s the power wiring is already above the finished roof 2 Units that are mounted on structural steel above the finished roof unless the steel is blocking the 4 1 2 diameter sleeve in the base of the unit This applies to units with or without a factory installed disconnect switch CAUTION The 4 1 2 sleeve must be sealed after the power wiring has been routed to prevent pos sible condensation problems ...

Page 6: ...ugh the side entry must be sealed to prevent the entrance of water CONTROL WIRING MODEL DSC480 For bottom entry Figure 8 the control wiring should be routed 1 Up through the 2 1 4 O D tubing behind the control box 2 Through the positioned ty wrap on the outside of the control box 3 Through the 1 3 8 snap bushing in the control box 4 Through the 2 ty wraps positioned in the control box 5 Connect th...

Page 7: ...FIG 9 CONTROL WIRING CONNECTIONS WITHOUT STATUS PANEL 530 25 N3Y Unitary Products Group 7 ...

Page 8: ...FIG 10 CONTROL WIRING CONNECTIONS WITH STATUS PANEL 530 25 N3Y 8 Unitary Products Group ...

Page 9: ...FIG 11 CONTROL WIRING CONNECTIONS SOLID STATE CONTROL WITH STATUS PANEL FIG 12 CONTROL WIRING CONNECTIONS SOLID STATE CONTROL WITH STATUS PANEL 530 25 N3Y Unitary Products Group 9 ...

Page 10: ...air fans 4 Based on three 75ÉC insulated copper conductors in steel conduit 2 Rated at a 45ÉET and a 130ÉCT 5 Based on a 3 voltage drop 3 Dual element time delay type 6 A 575 to 460 volt transformer is provided for these motors ELECTRICAL DATA UNITS WITHOUT EXHAUST AIR FANS 1 DSC Model Supply Air Blower Motor HP Exhaust Air Fan Motors 1 Phase Unit Ampacity Amps Max Fuse Size 2 Amps Min Wire Size 3...

Page 11: ...g FF 1 1 2 Pipe 360 480 Drain Conn GG 2 5 8 KO 360 480 Gas Heat Piping1 HH 2 3 8 KO 360 Gas Heat Piping2 JJ 1 1 8 KO 360 480 Control Wiring KK 3 5 8 KO 480 Power Wiring LL 3 5 8 KO 360 Power Wiring 1 Heating Option G560 G800 2 Heating Option G400 DIM MODEL DSC 360 480 A 164 184 B 32 32 C 100 120 D 100 120 E 4 5 8 F 5 G 5 5 8 H 11 1 4 J 42 K 55 1 2 L 65 M 73 N 57 3 8 77 1 2 FRONT Control Box Side 3...

Page 12: ... by the unit is absorbed in the chamber and not transmitted to the condi tioned space The chamber may be constructed of fiberglass duct or metal duct lined with sound absorption material Ceiling return grilles should be located a minimum of 12 feet from the end of the sound chamber In every installation a return air duct must be installed to the unit FILTERS All filters being used in these units a...

Page 13: ...tside and return air dampers should be checked to make sure they operate freely and close tightly It may be necessary to readjust the linkage between the damper motor and the blades due to loosening in shipment Readjust linkage as follows 1 Turn the minimum outside air adjuster to the 100 outside air position All return air damper blades should be fully closed Be sure that the spring return damper...

Page 14: ...oses in the compressor control circuit NOTE The above operation is for intermittent fan operation For continuous operation the fan switch on the room thermostat or the status panel should be manually closed to energize 7R 6 Relay contact 1R closes and energizes 1M coil which starts the No 1 compressor At the same time 4M coil is energized to start the condenser fans 7 If the room temperature conti...

Page 15: ...ll not allow outdoor air to enter the unit during high humidity conditions except at a lower outdoor temperature During dry conditions air is introduced at a higher ambient The outdoor and return air dampers are controlled by the logic panel The discharge sensor acts as a modulating low limit which senses the temperature of the air leaving the evaporator coil If at any time during the cooling cycl...

Page 16: ...he compressor un loading solenoid which loads the compressor 9 The compressor short cycle time and low voltage protection is part of the solid state compressor protection module It prevents a compressor from starting unless it has been off for five minutes It also monitors the voltage of the 120 volt control circuit and will shut down the compressor if the 120 volt control voltage drops below 85 æ...

Page 17: ...erence line The recommended deflection force is as follows e Tension new belts at the maximum deflection force recommended for the belt section Check the belt ten sion at lease two times during the first 24 hours of operation Any retensioning should fall between the minimum and maximum deflection force values f After adjusting retighten nuts A 5 All pulleys are factory aligned 6 All supply air mot...

Page 18: ...f operation check all belts and pulleys for tightness and align ment WARNING Failure to properly adjust the total system CFM can result in extensive blower damage FIG 17 HOLE LOCATIONS FOR SUPPLY AIR CFM CHECK FIG 18 PRESSURE DROP ACROSS A DRY EVAPORATOR COIL VS SUPPLY AIR CFM MODEL OF NOMINAL CFM 80 90 100 110 120 CFM DSC360 9600 10800 12000 13200 14400 DSC480 12800 14400 16000 17600 19200 MASTER...

Page 19: ...Off On On Fan Compr 1 On O S A dampers operate to setting of mixed air control Compr 1st Stage Cool Off St 1 Cpr Auto On Off Off Off On Off Off On Fan Compr 1 On with O S A dampers open to min position Compr 2nd Stage Cool Off St 1 St 2 Cpr Auto On Off Off Off On On Off On Fan Compr 1 2 run with O S A dampers open to min position Heat 1st Stage Heat St 1 Off Auto On Off On Off Off Off Off On Heat ...

Page 20: ...FIG 19 FIXED OUTDOOR AIR ADJUSTMENT FIG 20 EXHAUST AIR PERFORMANCE 530 25 N3Y 20 Unitary Products Group ...

Page 21: ...haust Air 022 028 035 042 050 Return Air Damper for Economizer End Duct Connection 179 226 279 338 402 Return Air Damper for Economizer Side by Side Btm Duct 077 097 120 145 173 2 30 Efficient Filters1 007 009 011 014 016 Bag Type Filters1 056 071 089 107 127 End Duct Connections2 143 181 224 271 323 480 12800 14400 16000 17600 19200 G560 Gas Heat 038 049 06 073 086 G800 Gas Heat 051 065 08 097 11...

Page 22: ...W SP BHP KW SP BHP KW SP BHP KW 900 1 12 8 84 7 55 0 75 10 11 8 76 0 30 11 59 10 03 950 1 42 9 73 8 44 1 05 11 17 9 66 0 60 12 73 11 02 1000 1 72 10 59 9 16 1 36 12 19 10 55 0 92 13 78 11 96 0 42 15 45 13 49 1050 2 00 11 50 9 95 1 66 13 16 11 40 1 23 14 78 12 86 0 76 16 56 14 53 0 21 18 45 16 23 1100 2 30 12 27 10 62 1 98 14 10 12 24 1 58 15 83 13 84 1 10 17 61 15 49 0 55 19 54 17 28 1150 2 62 13 ...

Page 23: ... 1Mand 2M If however a low or high pressure cutout opens the lockout relay 10R or 11R will be energized Since the voltage across 10R or 11R will exceed 100V the voltage across 1M or 2M will be too low to pull in the contactors The normally closed contacts of 10R or 11R will open the circuit in series with the low or high pressure cutout When these contacts automatically close the lockout circuit c...

Page 24: ... Check the compressor amps with the unit data plate 8 After approximately 15 minutes of operation check the liquid line sight glasses for a proper liquid refrigerant seal in each of the refrigerant circuit s 9 Next increase the setting of the room thermostat until the heating contacts are energized 10 Refer to the proper heating installation and operation instruction for the correct heating sequen...

Page 25: ...After the unit is functioning properly instruct the owner and operator on how to operate the unit Replace all panels before leaving the job site 530 25 N3Y Unitary Products Group 25 ...

Reviews: