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Thermostat Designations

See unit wiring diagram for power supply connections.
If the indoor unit is not equipped with a blower relay, one must
be field supplied and installed.

Do not connect C (common) connection between indoor unit
and thermostat except when required by the indoor thermostat.
Refer to thermostat installation instructions.  C (common)
connection between indoor unit and outdoor unit required for
proper operation.

Figure 4

Refrigerant Piping

If the 4SCU18LT 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 set and/or indoor
coil will be used to complete the system, refer to this section
as well as the section that follows entitled - 

Flushing

Existing Line Set and Indoor Coil

.

If this  unit is being matched with an approved line set or
indoor coil which was previously charged with R-22
refrigerant, the line set and coil must be flushed prior to
installation.  If the unit is being used with and existing indoor
coil which was equipped with a liquid line which served as a
metering device (RFCI), the liquid line must be replaced prior
to the installation of the 4SCU18LT unit.

Field refrigerant piping consists of liquid and suction lines
from the outdoor unit (sweat connections) to the indoor coil
(flare or sweat connections).

Select line set diameters from Table 2 to ensure that oil
returns to the compressor.  Size vertical suction riser to
maintain minimum velocity at minimum capacity.
Recommended line length is 50’ or less.  If more than 50’
line set is required, contact Technical Services.  Table 2
shows the diameters for line sets up to 100’ although vertical
lift applications and trapping requirements need to be
reviewed with Technical Services for line sets over 50’.

Installing Refrigerant Line

During the installation of an air conditioning system, it is
important to properly isolate the refrigerant line to prevent
unnecessary vibration.  Line set contact with the structure
(wall, ceiling, or floor) may cause objectionable noise when
vibration is translated into sound.  As a result, more energy
or vibration can be expected.  Close attention to line set
isolation must be observed.

Following are some points to consider  when placing and
installing a high-efficiency outdoor unit:

1. Install line voltage power supply to unit from a properly
sized disconnect switch.  Any excess high voltage field wiring
should be trimmed or secured away from the low voltage
field wiring.

2. Ground unit at unit disconnect switch or to an earth ground.
To facilitate conduit, a hole is in the bottom of  the  control
box.  Connect conduit to the control box using a proper
conduit fitting.  Units are approved for use only with copper
conductors.  24V Class II circuit connections are made in
the low voltage junction box.  Refer to Figure 4 for high
voltage field wiring diagram.  A complete unit wiring diagram
is located inside the unit control box cover.

3. Install room thermostat on an inside wall that is not subject
to drafts, direct sunshine, or other heat sources.

4. Install low voltage wiring from outdoor to indoor unit and
from thermostat to indoor unit (See Figure 5).

5. Do not bundle any excess 24V control wire inside control
box.  Run control wire through installed wire tie and tighten
wire tie to provide low voltage strain relief and to maintain
seperation of field-installed low and high voltage circuits.

506254-01

Page 4 of  25

Issue  0912

Содержание 4SCU18LT Series

Страница 1: ...injury death or property damage Use appropriate safety gear including safety glasses and gloves when installing this equipment WARNING Installation and servicing of air conditioning equipment can be hazardous due to internal refrigerant pressure and live electrical components Only trained and qualified service personnel should install or service this equipment Installation and service performed by...

Страница 2: ...onnel and do not supersede any national or local codes in any way The installation must comply with all provincial state and local codes as well as the National Electrical Code U S or Canadian Electrical Code Canada Compliance should be determined prior to installation 4SCU18LT condensing units use R410Awhich is an ozone friendly HFC refrigerant The unit must be installed with a matching indoor co...

Страница 3: ...of 2 or 2 per 5 This will prevent ice from building up under the unit during a defrost cycle Refer to following roof mounting section for barrier construction if unit must face prevailing winter winds If unit coil cannot be mounted away from prevailing winter winds a wind barrier should be constructed See Figure 3 Size the barrier at least the same height and width as the outdoor unit Mount barrie...

Страница 4: ...s the diameters for line sets up to 100 although vertical lift applications and trapping requirements need to be reviewed with Technical Services for line sets over 50 Installing Refrigerant Line During the installation of an air conditioning system it is important to properly isolate the refrigerant line to prevent unnecessary vibration Line set contact with the structure wall ceiling or floor ma...

Страница 5: ...e the refrigerant piping This will help to prevent oxidation and the introduction of moisture into the system 3 Use silver alloy brazing rods 5 or 6 silver alloy for copper to copper brazing or 45 silver alloy for copper to brass or copper to steel brazing which are rated for use with R410A refrigerant 4 Remove the Schrader core assemblies before brazing to protect them from damage due to extreme ...

Страница 6: ...d separately and which is approved for use with R410A refrigerant in the liquid line at the indoor coil see Refrigerant Metering Device on page 9 When flushing existing line set and or indoor coil be sure to empty all existing traps Residual mineral oil can act as an insulator preventing proper heat transfer It can also clog thethermalexpansionvalve reducingsystemperformance and capacity Failure t...

Страница 7: ...Figure 7 Figure 8 506254 01 Page 7 of 25 Issue 0912 ...

Страница 8: ...em Refer to the gauges after shutdown to confirm that the entire system is completely void of refrigerant Disconnect the liquid and suction lines from the existing outdoor unit If the existing outdoor unit is equipped with manual shutoff valves AND new R 22 refrigerant will be used to flush the system Start the existing R 22 refrigerant system in cooling mode and close the liquid line valve Pump a...

Страница 9: ... on the inverted R 22 cylinder and the gauge set valves Pump the remaining refrigerant out of the recovery machine and turn the machine off 10 Use nitrogen to break the vacuum on the refrigerant lines and indoor coil before removing the recovery machine gauges and R 22 refrigerant drum Re install pressure tap valve cores into the 4SCU18LT unit s service valves 11 Install the fixed orifice or therm...

Страница 10: ...chrader Port 1 Remove the service port cap with an adjustable wrench 2 Connect gauge to the service port 3 When testing is completed replace service port cap Tighten finger tight then an additional 1 6 turn To Open Liquid or Suction Line Service Valve Remove stem cap with an adjustable wrench Use service wrench with a hex head extension to back the stem out counterclockwise as far as it will go Us...

Страница 11: ...l vary with lenths Check all joints for leaks Purge nitrogen and R410A mixture Correct any leaks and rechecks Evacuation Evacuating the system of noncondensables is critical for proper operation of the unit Noncondensables are defined as any gas that will not condense under temperatures and pressures present during operation of an air conditioning system Noncondensables and water vapor combine wit...

Страница 12: ...rogen cylinder with pressure regulator set to 150 psig and purge the hose Open the manifold gauge valves to break the vacuum in the line set and indoor unit Close the manifold gauge valves 7 Shut off the nitrogen cylinder and remove the manifold gauge hose from the cylinder Open the manifold gauge valves to release the nitrogen from the line set and indoor unit 8 Reconnect the manifold gauge to th...

Страница 13: ...s based on a matching indoor coil and outdoor coil with 15 line set For varying lengths of line set refer to Table 5 for refrigerant charge adjustment A blank space is provided on the unit rating plate to list the actual field charge Table 5 If the system is void of refrigerant clean the system using the procedure described below 1 Use dry nitrogen to pressurized the system and check for leaks Rep...

Страница 14: ...e to liquid line service valve 2 Close manifold gauge set valves Connect the center manifold hose to an upright cylinder of R410A 3 If room temperature is below 70 F set the room thermostat to call for heat This will create the necessary load for properly charging the system in the cooling cycle 4 Use a digital thermometer to record the outdoor ambient temperature 5 When the heating demand has bee...

Страница 15: ...ch temperature or recover refrigerant from the system to increase the approach temperature Check Charge Using Normal Operating Pressures Use Table 8 to perform maintenance checks Table 8 is not a procedure for charging the system Minor variations in these pressures may be due to differences in installations Significant deviations could mean that the system is not properly charged or that a problem...

Страница 16: ... 147 344 147 348 150 363 144 105 372 148 391 149 402 151 405 148 115 413 151 438 153 456 154 447 152 High Capacity 24 36 48 60 Outdoor Coil Entering Air Temp F L S L S L S L S 65 212 137 210 141 237 137 248 123 75 254 139 247 143 286 139 293 128 85 295 142 298 145 330 140 337 132 95 337 144 349 147 374 142 382 137 105 379 146 400 149 418 144 427 142 115 424 149 451 151 462 145 471 146 506254 01 Pa...

Страница 17: ...r of times consecutively pause and then repeat the process To identify a flash code number count the number of consecutive flashes Refer to Table 9 on page 18 and Table 10 on page 19 for information on the flash codes Every time the module powers up the lastALERT LED flash code that occurred prior to shutdown is displayed for 60 seconds The module will continue to display the previous flash code u...

Страница 18: ...Table 9 Flash Codes 506254 01 Page 18 of 25 Issue 0912 ...

Страница 19: ...Table 10 Flash Codes cont 506254 01 Page 19 of 25 Issue 0912 ...

Страница 20: ...Table 11 Miswired Module Troubleshooting 506254 01 Page 20 of 25 Issue 0912 ...

Страница 21: ...the unit should be gauged and refrigerant charge checked Refer to the Refrigerant Charging section on page 12 Indoor Coil 1 Clean coil if necessary 2 Check connecting lines and coils for evidence of oil leaks 3 Check condensate pan line and clean if necessary Indoor Unit 1 Clean or change filters 2 Adjust blower speed for cooling Measure the pressure drop over the coil to determine the correct blo...

Страница 22: ... _________ Compressor Amperage ________ Outdoor Fan __________ Maximum Fuse or Circuit Breaker ________________________ Electical Connections Tight Indoor Filter Clean Supply Voltage Unit Off __________ Indoor Blower RPM ___________________ S P Drop Over Indoor Dry ____________________ Outdoor Coil Entering Air Temperature ________ Voltage with Compressor Operating __________ Discharge Pressure __...

Страница 23: ...506254 01 Page 23 of 25 Issue 0912 WIRE DIAGRAM ...

Страница 24: ...stallation date and location c an accurate description of the problem WARRANTY LIMITATIONS 1 This warranty is void if the covered equipment is removed from the original installation site 2 This warranty does not cover damage or defect resulting from a Flood wind fire lightning mold or installation and operation in a corrosive atmosphere or otherwise in contact with corrosive materials chorine fluo...

Страница 25: ... lightening strike to the home or unit corrosive atmosphere contact with corrosive material Chlorine fluorine salt recycled waste water fertilizers or other damaging substances or other conditions beyond the control of Allied 2 Use of parts accessories or refrigerant not compatible with the unit 3 Modification change or alteration of the unit except as expressly directed in writing by Allied 4 Imp...

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