126115-UIM-D-0306
Unitary Products Group
5
6.
Install the TXV equalizer line into the vapor line as follows:
a.
Select a location on the vapor line for insertion of the equal-
izer line which will not interfere with TXV bulb placement.
b.
Use an awl to punch through the suction tube and insert the
awl to a depth to achieve a 1/8” diameter hole.
7.
Install TXV equalizer line in 1/8” hole previously made in vapor
line. Equalizer line should not be bottomed out in the vapor line.
Insert equalizer line at least 1/4” in the vapor line. Braze equalizer
line making sure that tube opening is not brazed closed.
All connections to be brazed are copper-to-copper and should be
brazed with a phosphorous-copper alloy material such as Silfos-5 or
equivalent. DO NOT use soft solder.
Install the TXV bulb to the vapor line near the equalizer line, using the
two bulb clamps furnished with the TXV assembly. Ensure the bulb is
making maximum contact. Refer to TXV installation instruction for view
of bulb location.
a.
Bulb should be installed on a horizontal run of the vapor line if
possible. On lines under 7/8" OD the bulb may be installed on
top of the line. With 7/8" OD and over, the bulb should be
installed at the position of about 2 or 10 o'clock.
b.
If bulb installation is made on a vertical run, the bulb should
be located at least 16 inches from any bend, and on the tub-
ing sides opposite the plane of the bend. The bulb should be
positioned with the bulb tail at the top, so that the bulb acts as
a reservoir.
c.
Bulb should be insulated using thermal insulation provided to
protect it from the effect of the surrounding ambient tempera-
ture.
SECTION V: EVACUATION
It will be necessary to evacuate the system to 500 microns or less. If a
leak is suspected, leak test with dry nitrogen to locate the leak. Repair
the leak and test again.
To verify that the system has no leaks, simply close the valve to the vac-
uum pump suction to isolate the pump and hold the system under vac-
uum. Watch the micron gauge for a few minutes. If the micron gauge
indicates a steady and continuous rise, it’s an indication of a leak. If the
gauge shows a rise, then levels off after a few minutes and remains
fairly constant, it’s an indication that the system is leak free but still con-
tains moisture and may require further evacuation if the reading is
above 500 microns.
SECTION VI: SYSTEM CHARGE
The factory charge in the outdoor unit includes enough charge for the
unit, a 15 ft. line set, and the smallest indoor coil match-up. Some
indoor coil matches may require additional charge. See tabular data
sheet provided in unit literature packet for charge requirements.
The “TOTAL SYSTEM CHARGE” must be permanently stamped on the
unit data plate.
Total system charge is determined as follows:
1.
Determine outdoor unit charge from tabular data sheet.
2.
Determine indoor coil adjustment from tabular data sheet.
3.
Calculate the line charge using the tabular data sheet if line length
is greater than 15 feet.
4.
Total system charge = item 1 + item 2 + item 3.
5.
Permanently stamp the unit data plate with the total amount of
refrigerant in the system.
Use the following charging method whenever additional refrigerant is
required for the system charge.
If a calibrated charging cylinder or accurate weighing device is avail-
able, add refrigerant accordingly. Otherwise, model-specific charging
charts are provided on the access panel of the unit. If mix matched TXV
indoor coils are used with these models, the following subcooling charg-
ing method must be used. Superheat charging charts are not valid with
TXV equipped systems.
SUBCOOLING CHARGING METHOD - MIXED MATCH
COILS
The recommended subcooling is 10°F
1.
Set the system running in the cooling mode by setting the thermo-
stat at least 6°F below the room temperature.
2.
Operate the system for a minimum of 15-20 minutes.
3.
Refer to the tabular data sheet for the recommended airflow and
verify this indoor airflow (it should be about 400 SCFM per ton).
4.
Measure the liquid refrigerant pressure P and temperature T at the
service valve.
5.
Calculate the saturated liquid temperature ST from Table 2.
6.
Subcooling temperature TC = Saturated Temperature (ST) - Liquid
Temp (T).
Add charge if the calculated subcooling temperature TC in Step 6 is
lower than the recommended level. Remove and recover the refrigerant
if the subcooling TC is higher than the recommended level. See Table
2.
Check flare caps on service ports to be sure they are leak tight. DO
NOT OVERTIGHTEN (between 40 and 60 inch - lbs. maximum).
Dry nitrogen should always be supplied through the tubing while it
is being brazed, because the temperature required is high enough
to cause oxidation of the copper unless an inert atmosphere is pro-
vided. The flow of dry nitrogen should continue until the joint has
cooled. Always use a pressure regulator and safety valve to insure
that only low pressure dry nitrogen is introduced into the tubing.
Only a small flow is necessary to displace air and prevent oxidation.
In all cases, mount the TXV bulb after vapor line is brazed and has
had sufficient time to cool.
Do not leave the system open to the atmosphere.
Refrigerant charging should only be carried out by a qualified air
conditioning contractor.
Compressor damage will occur if system is improperly charged. On
new system installations, charge system per tabular data sheet for
the matched coil and follow guidelines in this instruction.
Example: The pressure P and temperature T measured at the liq-
uid service port is 196 psig and 90°F, respectlvely. From Table 2,
the saturated temperature for 196 psig is 100°F. The subcooling
temperature TC = 100°-90°=10°F
