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507607-03

Issue 1827

Page 13 of 23

2.  Attach high pressure gauge set and operate unit for 

several minutes to allow system pressures to stabilize.

3.  Compare stabilized pressures with those provided in 

the charge tables on inside control box cover. Minor 

variations in these pressures may be expected due 

to  differences  in  installations.  Significant  differences 

could mean that the system is not properly charged 

or that a problem exists with some component in the 

system. Pressures higher than those listed indicate 

Figure 14. Control Board

Non-Communicating System

For systems with a non-communicating thermostat, the system 

will operate based on the settings of the jumpers located on the 

control board. All system settings must be done at the control 

board.

Communicating System

For a communicating system, the Comfort Sync thermostat 

must  be  used.  The  complete  configuration  of  the  outdoor  unit 

is performed using the Comfort Sync thermostat. For complete 

details on how to integrate this unit into a Comfort Sync-enabled 

system, please refer to the Comfort Sync Wi-Fi installer’s system 

setup guide.

100 90 70 50

100 90 70 50

100 90 70 50

100 90 70 50

100 90 70 50

55 50 45 40

55 50 45 40

55 50 45 40

55 50 45 40

ON

OFF

30

PSC

LO

PS

HI

PS

Y1

OUT

Y2

OUT

OUT
O

R

I+

I -

C

DS

O

Y1

Y2

L

W

COIL

 AMB 

DIS

OPEN = OFF OPEN = 90 F

2ND ST

AGE

LOCK IN

55 F

50 F

45 F

40 F

DEFROST

TERMINA

TION

100 F

90 F

70 F

50 F

COMP

 SHIFT

DELA

Y

J4

J3

FA

N

CYCLING

J1

J2

ECM Y1

ECM Y2

COM

PARK

FA

N

PWM

DS TO R

7-Segment 

Display

Push 

Button

J2 (Two-Stage 

Heat Pump Only) 

Second Stage Lock-In 

Temperature

55 Degree 

Target

50 Degree 

Target

45 Degree 

Target

40 Degree 

Target 

(Default)

J4 (HP Only)

Compressor Shift

 

Delay

30 Second 

Delay 

(Default)

No Delay

J1 (HP Only)

Defrost Termination Temperature

100 Degree 

Target

90 Degree 

Target

70 Degree 

Target

50 Degree 

Target

Default When 

Jumper is 

Removed or 

Missing

90

J3 (All Units)

Fan De-Icing 

Jumper ON 

Fan On 5 Minutes

Jumper OFF 

Digable (Default)

DS to R Jumper (Two-Stage Heat Pump Only)

Break off DS to R jumper if Enhanced Dehumidification Accessory (EDA) is used 

with Comfort Sync thermostat (two-stage units only).

that the system is overcharged. Pressures lower than 

those listed indicate that the system is undercharged. 

Verify adjusted charge using the approach method.

4.  Use the same digital thermometer to check liquid line 

temperature.

5.  Subtract the outdoor ambient temperature from the 

liquid line temperature to determine the approach 

temperature.

6.  Compare the approach value with those shown on 

charge label located on back of control box cover

Summary of Contents for 4SCU 16 LS Series

Page 1: ...personal injury death or property damage Use appropriate safety gear including safety glasses and gloves when installing this equipment WARNING Risk of electrical shock Disconnect all remote power sup...

Page 2: ...lbs Service Port Caps 8 ft lbs Sheet Metal Screws 16 in lbs 8 Machine Screws 16 in lbs 10 Machine Screws 28 in lbs Compressor Bolts 90 in lbs Inspection of Shipment Upon receipt of equipment carefull...

Page 3: ...it properly can result in personal injury or death WARNING Line voltage is present at all components when unit is not in operation on units with single pole contactors Disconnect all remote electric p...

Page 4: ...to terminal C Single wire to terminal C Unused wires Unused wires Comfort Sync Thermostat with a Non Communicating Outdoor Unit ENABLED FURNACE Comfort Sync THERMOSTAT NON COMMUNICATING OUTDOOR AIR CO...

Page 5: ...evice section Refrigerant Piping If the 4SCU16 LS unit is being installed with a new indoor coil and line set the refrigerant connections should be made as outlined in this section If an existing line...

Page 6: ...ne only 8 8 Tape or Wire Tie Strap the vapor line to the joist or rafter at 8 intervals then strap the liquid line to the vapor line Floor Joist or Roof Rafter Metal Sleeve Floor Joist or Roof Rafter...

Page 7: ...507607 03 Issue 1827 Page 7 of 23 Figure 9 Refrigerant Line Sets Installing Vertical Runs Figure 10 Flushing Connections...

Page 8: ...voltage and line voltage connections to the new outdoor unit Do not turn on power to the unit or open the outdoor unit service valves at this time 4 Remove the existing R 22 refrigerant flow control o...

Page 9: ...ling the higher system operating pressures The gauges should be rated for use with pressures 1 800 on the high side and a low side of 30 vacuum to 250 psi with dampened speed to 500 psi Gauge hoses mu...

Page 10: ...w R410A into the line set and indoor unit Weigh in a trace amount of R410A A trace amount is a maximum of 2 oz of refrigerant or 3 lbs pressure Close the valve on the R410A cylinder and the valve on t...

Page 11: ...et disconnect the manifold hose from the vacuum pump Open the service valves to break the vacuum in the line set and indoor unit Start Up If unit is equipped with a crankcase heater it should be energ...

Page 12: ...perature 5 When the heating demand has been satisfied switch the thermostat to cooling mode with a set point of 68 F When pressures have stabilized use a digital thermometer to record the liquid and s...

Page 13: ...5 50 45 40 55 50 45 40 55 50 45 40 ON OFF 30 PSC LO PS HI PS Y1 OUT Y2 OUT OUT O R I I C DS O Y1 Y2 L W COIL AMB DIS OPEN OFF OPEN 90 F 2ND STAGE LOCK IN 55 F 50 F 45 F 40 F DEFROST TERMINATION 100 F...

Page 14: ...unit control circuit is isolated from power and the field supplied relays bypass the outdoor thermostats An amber indicating light simultaneously comes on to remind the homeowner that the unit is ope...

Page 15: ...ers Verify configuration of system Communicating systems only Reconfigure the system Replace control if heating or cooling is not available Only applicable in the communicating mode not in startup Exi...

Page 16: ...he recommended upper limit of 279 F Discharge line high temperature error count reached 5 strikes Confirm that the system is properly charged with refrigerant Check system operating pressures and comp...

Page 17: ...C 2AC 1 Stage AC 1HP 1 Stage AC 2HP Power Up 7 Segment Display String 2 H P ___ ___ ___ ___ ___ ___ Unit Type Stages No Capacity No Fan Profile Power Up Reset following display of self discovered conf...

Page 18: ...1 E pause 250 pause E pause 231 Next codes up to 10 are shown using same method If there are no error codes stored E pause 000 Fault Memory Clear After the fault memory is cleared the following string...

Page 19: ...ode string d pause F Outdoor fan RPM pause A ambient temp displayed pause repeat mode IMPORTANT On 2 stage unit R to DS link must be cut and correct RPM outdoor fan profile selected for outdoor fan to...

Page 20: ...will automatically exit Field Test Mode If 10 second period expires or push button is held for less than 3 seconds control will automatically exit Field Test Mode and go into Idle Mode without storin...

Page 21: ...nd all access panels must be in place any time the unit is in operation Some systems are equipped with an electronic air cleaner designed to remove the majority of airborne particles from the air pass...

Page 22: ..._____________ Rated Load Ampacity _______________ Compressor Amperage _________________ OutdoorFan _____________________ Maximum Fuse or Circuit Breaker ____________________________ Electrical Connect...

Page 23: ...507607 03 Issue 1827 Page 23 of 23 Figure 15 4SCU16LS124 36 48 60 Wiring Diagram...

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