035-20401-001 Rev. A (0904)
Unitary Products Group
5
See "System Charge” section for checking and recording system
charge.
SECTION IV: INSTALLATIONS REQUIRING
TXV
For installations requiring a TXV, the following are the basic steps for
installation. For detailed instructions, refer to the Installation Instructions
accompanying the TXV kit.
Install TXV kit as follows:
1.
First, relieve the holding charge by depressing the Schrader valve
located in the end of the liquid line.
2.
After holding charge is completely discharged, loosen and remove
the liquid line fitting from the orifice distributor assembly. Note that
the fitting has
right
hand
threads
.
3.
Remove the orifice from the distributor body using a small diame-
ter wire or paper clip. Orifice is not used when the TXV assembly
is installed.
4.
After orifice is removed, install the thermal expansion valve to the
orifice distributor assembly with supplied fittings. Hand tighten and
turn an additional 1/8 turn to seal. Do not overtighten fittings.
5.
Reinstall the liquid line to the top of the thermal expansion valve.
Hand modify the liquid line to align with casing opening.
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 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: ELECTRICAL CONNECTIONS
GENERAL INFORMATION & GROUNDING
Check the electrical supply to be sure that it meets the values specified
on the unit nameplate and wiring label.
Power wiring, control (low voltage) wiring, disconnect switches and over
current protection must be supplied by the installer. Wire size should be
sized per NEC requirements.
The complete connection diagram and schematic wiring label is located
on the inside surface of the unit service access panel and this instruc-
tion.
FIELD CONNECTIONS POWER WIRING
1.
Install the proper size weatherproof disconnect switch outdoors
and within sight of the unit.
2.
Remove the screws at the bottom of the corner cover. Slide corner
cover down and remove from unit. See Figure 5.
3.
Run power wiring from the disconnect switch to the unit.
4.
Remove the service access panel to gain access to the unit wiring.
Route wires from disconnect through power wiring opening pro-
vided and into the unit control box.
5.
Install the proper size time-delay fuses or circuit breaker, and
make the power supply connections.
6.
Energize the crankcase heater if equipped to save time by pre-
heating the compressor oil while the remaining installation is com-
pleted.
Never attempt to repair any brazed connections while the system is
under pressure. Personal injury could result.
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.
All field wiring must USE COPPER CONDUCTORS ONLY and
be in accordance with Local, National Fire, Safety & Electrical
Codes. This unit must be grounded with a separate ground
wire in accordance with the above codes.
FIGURE 5:
Typical Field Wiring
CONTROL
WIRING
POWER
WIRING
CORNER
COVER
SERVICE
ACCESS
PANEL
