5169032-UIM-C-0416
Johnson Controls Unitary Products
7
SECTION V: COIL METERING DEVICES
A piston or a TXV is to be installed in the field. There is an installation
manual that comes with the TXV kit. It is recommended to install the
piston or TXV kit prior to installation of coil and brazing of line set. Until
brazing is completed and cooled, the TXV sensing bulb must not be
installed.
The outdoor technical guide for outdoor units should be consulted for
required piston or TXV on the indoor coil. The piston and the Schrader
core are supplied with the outdoor unit. When the piston is used instead
of the TXV, the Schrader core is installed in the suction line equalizer
connection port and is capped with the supplied plastic cap. The
Schrader core must not be installed if the TXV is installed, because the
TXV equalizer line attaches to the equalizer connection port.
PISTON INSTALLATION
Install Schrader Valve Core and
Piston
as follows:
1.
After holding charge is completely discharged, remove black plas-
tic cap from equalizer connection port on the vertical part of the
vapor line.
2.
Distributor position must be adjusted to allow the preformed liquid
line assembly to properly line up with the hole in the tubing access
panel. Raise the distributor body approximately 2” toward the top of
the coil or what would be the top of the coil if coil was in the upflow
position. See Figure 9. Adjust as necessary.
3.
Install Schrader valve core supplied with the outdoor unit into the
equalizer fitting connection port using a valve core tool.
4.
Loosen and remove the liquid line connection nut and the sealing
disc from the distributor assembly. Note that the fitting has right
hand threads.
5.
Slide the nut over the liquid line to be installed, and discard the
seal disc.
6.
Install required size piston into the distributor. Refer to supplied
Tabular Data Sheet for specific piston size and indoor coil match
up. See Figure 10.
7.
Verify that the Teflon washer is still in place in the distributor open-
ing. See Figure 10.
8.
After piston is installed, install the liquid line to the top of the pis-
ton/distributor assembly. Hand tighten, and turn an additional 1/4
turn to seal. Do not over tighten fittings.
9.
Replace black plastic cap on unused equalizer fitting connection
port.
10. After line set is installed, leak test the system.
THERMOSTATIC EXPANSION VALVE (TXV) INSTAL-
LATION
The following are basic steps for installation. For detailed instructions,
refer to the Installation Instructions accompanying the TXV kit. Install
TXV kit as follows:
1.
Relieve the holding charge by depressing Schrader core on the
suction manifold stub out.
2. After holding charge is completely discharged, loosen and remove
the Schrader core.
CAUTION
COIL UNDER PRESSURE.
Verify that pressure has been released by depressing schrader valve
core shown in Figure 2.
The coil requires a metering device to be added.
See outdoor unit documentation for correct TXV or piston to be used.
NOTICE
To prevent moisture and contaminates from entering the system, the
coil should not be open to atmosphere for extended periods of time. If
the coil cannot be brazed into the refrigeration system during a rou-
tine installation period, the ends should be temporarily closed or
plugged. For a short term delay, use masking tape over the ends of
the copper tubing to close the tube from the air. For a longer term
delay, use plugs or caps. There is no need to purge the coil if this pro-
cedure is followed.
WARNING
Failure to install Schrader Valve Core in the vapor line
equalizer con-
nection port
for piston applications could result in total refrigerant loss
of the system!
!
!
FIGURE 9:
Recommended Distributor Adjustment
FIGURE 10:
Piston Installation
CAUTION
Do not overtorque. Do not use slip joint pliers. This will distort the alu-
minum distributor and the brass fitting (potentially causing leaks).
CAUTION
Outdoor unit model numbers ending with an “H” have a factory
installed hard start kit which is required when a TXV is installed. Out-
door unit model numbers with no “H” ending do not require a hard
start kit unless local regulations dictate it.
IMPORTANT
Refer to the Technical Guide for the unit to determine the proper TXV
kit to be used on this product.
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