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Page 10

# 504,910M

START-UP

1. Rotate fan to check for frozen bearings or binding.

2. Inspect all factory and field-installed wiring for loose

connections.

3. Open liquid line and suction line service valves to

release refrigerant charge (contained in outdoor unit)
into system. Replace and tighten caps. Use a backup
wrench on the suction and liquid valves when remov-
ing or replacing valve caps.

4. To open suction valve, remove hex cap and turn valve

stem fully open using an Allen (hex) wrench. To open
liquid valve, remove cap and turn valve stem until it is
fully open.

NOTE:

 When replacing valve caps, the caps should

be finger tight then tightened an additional 1/6 of a
turn.

5. Check voltage supply at the disconnect switch. the

voltage must be within the range listed on the unit
nameplate. If not, do not start equipment until the
power company has been consulted and the voltage
condition corrected.

6. Set thermostat for cooling demand, turn on power to

indoor blower and close the outdoor unit disconnect
switch to start the unit.

7. Recheck unit voltage with unit running. Power must be

within range shown on unit nameplate. Check amper-
age draw of unit. Refer to unit nameplate for correct
running amps.

Charging

This system is charged with R410A refrigerant which
operates at much higher pressures than R22. The liquid line
drier provided with the unit is approved for use with R410A.
Do not replace it with one designed for use with R22. 

This

unit is NOT approved for use with coils which use
capillary tubes as a refrigerant metering device.

Factory Charge

Units are factory charged with the amount of R410A
refrigerant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with 15'
line set. For varying lengths of line set, refer to Table 4 for
refrigerant charge adjustment.

4. Open both manifold valves and start vacuum pump.

5. Evacuate the line set and indoor unit to an absolute

pressure of 23mm (23,000 microns) of mercury
(approximately 1 in. of mercury). During the early
stages of evacuation, it is desirable to close the
manifold gauge valve at least once to determine if
there is a rapid rise in absolute pressure. A rapid rise
in pressure indicates a relatively large leak. If this
occurs, the leak testing procedure must be repeated.

NOTE

 – The term 

absolute pressure

 means the total

actual pressure with a given volume or system, above
the absolute zero of pressure. Absolute pressure in a
vacuum is equal to atmospheric pressure minus
vacuum pressure.

6. When the absolute pressure reaches 23mm of

mercury, close the manifold gauge valves, turn off the
vacuum pump, and disconnect the manifold gauge
center port hose from the vacuum pump. Attach the
manifold gauge center port hose to a nitrogen 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 the vacuum pump,

turn the pump on, and continue to evacuate the line
set and indoor unit until the absolute pressure does
not rise above .5mm (500 microns) of mercury within
a 20-minute period after shutting off the vacuum
pump and closing the manifold gauge valves.

9. When the absolute pressure requirement above has

been met, disconnect the manifold hose from the
vacuum pump and connect it to an upright cylinder of
R410A refrigerant. Open the manifold gauge valves to
break the vacuum in the line set and indoor unit.
Close manifold gauge valves and shut off R410A
cylinder and remove manifold gauge set.

Mineral oils are not compatible with R410A. If
oil must be added, it must be a polyol ester oil.

  IMPORTANT

Summary of Contents for SCU12M-024

Page 1: ...on and service performed by unqualified persons can result in property damage personal injury or death WARNING Risk of electrical shock Disconnect all remote power supplies before installing or servic...

Page 2: ...A B C 4 2 0 M 2 1 U C S n i 5 2 4 1 4 2 4 1 4 2 m m 5 3 6 6 1 6 6 1 6 0 3 0 M 2 1 U C S 6 3 0 M 2 1 U C S 2 4 0 M 2 1 U C S 8 4 0 M 2 1 U C S n i 3 3 4 1 2 3 4 1 4 2 m m 8 3 8 9 1 8 6 1 6 0 6 0 M 2 1...

Page 3: ...12M condensing units use R410A which is an ozone friendly HFC refrigerant This unit must be installed with a matching indoor coil and line set SCU12M units are designed for use in expansion valve TXV...

Page 4: ...SCU12M unit Field refrigerant piping consists of liquid and suction lines from the outdoor unit sweat connections to the indoor coil flare or sweat connections Flushing Existing Line Set and Indoor C...

Page 5: ...to flow back into the low side of the sys tem Disconnect the liquid and vapor lines from the existing outdoor unit 2 Remove the existing outdoor unit Set the new R410A unit and follow the brazing conn...

Page 6: ...that all of the R22 vapor is recovered Allow the recovery to pull a vacuum on the system NOTE A single system flush should remove all of the mineral oil from the existing refrigerant lines and indoor...

Page 7: ...using 4 Connect the external equalizer line to the equalizer port on the suction line splice 5 Strap the superheat sensing bulb to the suction header If installing an expansion valve on an indoor coil...

Page 8: ...r Suction Line Service Valve 1 Remove the stem cap with an adjustable wrench 2 Use a service wrench with a hex head extension to turn the stem clockwise to seat the valve Tighten it firmly 3 Replace t...

Page 9: ...s Check all joints for leaks Purge nitrogen and R410A mixture Correct any leaks and recheck IMPORTANT The leak detector must be capable of sensing HFC refrigerant Evacuation Evacuating the system of n...

Page 10: ...pen both manifold valves and start vacuum pump 5 Evacuate the line set and indoor unit to an absolute pressure of 23mm 23 000 microns of mercury approximately 1 in of mercury During the early stages o...

Page 11: ...he same digital thermometer used to check outdoor ambient temperature to check liquid line temperature Verify the unit charge using the approach method The difference between Refrigerant Charge Adjust...

Page 12: ...2 p m e T F e r u s s e r P g i s P 4 7 0 4 1 2 5 7 4 7 1 2 6 7 9 0 2 2 7 7 4 4 2 2 8 7 0 8 2 2 9 7 6 1 3 2 0 8 3 5 3 2 1 8 0 9 3 2 2 8 7 2 4 2 3 8 5 6 4 2 4 8 3 0 5 2 5 8 1 4 5 2 6 8 0 8 5 2 7 8 0 2...

Page 13: ...d installer or service agency At the beginning of each cooling season the system should be checked as follows 1 Clean and inspect condenser coil Coil may be flushed with a water hose Be sure the power...

Page 14: ...Page 14 504 910M 4 Check all wiring for loose connections 5 Check for correct voltage at unit with unit operating 6 Check amp draw on blower motor Unit nameplate _________ Actual _________...

Page 15: ...504 910M Page 15 Figure 7 Connection Diagram Part 534 638W...

Page 16: ...ligation in connection with the warranted product What is NOT Covered 1 Cabinets or cabinet pieces 2 Normal maintenance items such as filters fan belts fuses or other consumable items 3 Damage caused...

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