835966-UIM-E-0814
Johnson Controls Unitary Products
5
10.Release the refrigerant charge into the system in accordance with
the SYSTEM CHARGE procedures. Open the liquid line base valve
first and let pressures equalize. Then, open the suction line base
valve. When opening either valve, use an appropriate hex head
wrench and back seat the base valve by turning it counter clockwise
until it stops against the chamfered retaining wall, and then turn it
back 1/8 turn. If the service valve is a ball valve, use an adjustable
end wrench to turn valve stem one-quarter turn counterclockwise to
open. Do not overturn (or the valve stem may break or become dam-
aged).
11.To prevent leaks, replace base valve caps finger tight, and then
tighten the cap an additional 1/12 turn (1/2 hex flat).
12.Replace cap on service ports. Do not remove the flare caps from the
service ports except when necessary for servicing the system.
13. See “System Charge” section for checking and recording system
charge.
SECTION IV: INDOOR EXPANSION DEVICE
THERMOSTATIC EXPANSION VALVE
(
TXV) INSTAL-
LATIONS
Before accomplishing the following procedures, verify the proper TXV
kit to be installed on the coil distributor. Refer to supplied Tabular Data
Sheet for proper indoor coil match up and specific TXV kit.
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. Relieve nitrogen holding charge from the indoor coil by depressing
the Schrader valve stem located in the end of the suction line. After
nitrogen holding charge is completely discharged, cut the spundown
copper to allow installation of the suction line.
2. Slide indoor coil out of cabinet far enough to gain access to equal-
izer fitting on the suction line.
3. Before the suction line from the outdoor unit is brazed to the indoor
coil suction line, remove and discard black plastic cap from equalizer
fitting on the indoor coil suction line.
4. Loosen and remove distributor cap seal.
5. Install the TXV to the distributor assembly by hand tightening, and
then turn fitting an additional 1/4 turn to seal.
Do not overtighten fit-
tings.
6. Install the liquid line to the top of the TXV using the liquid line fitting
which is supplied with the indoor coil. Hand modify the liquid line to
align with casing opening. Hand tighten the liquid line on the TXV,
and tighten an additional 1/4 turn to seal.
7. Install the TXV liquid equalizer line onto the equalizer fitting of the
suction line. Hand tighten the 1/4” SAE nut to the equalizer fitting,
and tighten an additional 1/3 turn to seal.
8. Install the TXV bulb to the suction line near the equalizer line, using
the bulb clamp(s) furnished with the TXV assembly kit. Ensure the
bulb is making maximum contact. Refer to TXV kit installation
instructions for view of bulb location.
a.
Install the bulb on the suction line near the equalizer line with
the bulb horizontal to the suction line. On a suction line under
7/8” Outside Diameter (O.D.), install the bulb on top of the
line. On a suction line 7/8” O.D. or larger, install the bulb at
about the 2 or 10 o'clock position.
b.
If bulb must be installed vertically to the suction line, position
the bulb at least 16 inches (40.6 cm) from any bend and on
the opposite side of the bend plane. Positioned the bulb with
the bulb tail at the top, so that the bulb acts as a reservoir.
c.
Use thermal insulation provided to protect the bulb from the
effect of the surrounding ambient temperature. Cover the
bulb completely to insulate from air-stream.
9. Leak test system after outdoor unit is connected.
10.Slide indoor coil back into cabinet.
Do not connect manifold gauges unless trouble is suspected. Approxi-
mately 3/4 ounce of refrigerant will be lost each time a standard manifold
gauge is connected.
In all cases, mount the TXV bulb after vapor line is brazed and has
had sufficient time to cool.
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 provided.
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.
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. Soft solder is NOT to be used.
NOTICE
Do not install TXV onto distributor assembly until field supplied liquid
line is brazed onto the indoor coil liquid line and cooled.
Do not use slip joint pliers. Damage and distortion of distributor can
prevent proper seal. Use appropriate sized adjustable end wrench.
The schrader valve core from the TXV kit MUST NOT be installed in
the equalizer fitting when the TXV kit is installed. Poor system perfor-
mance or system failure could result.
Do not install TXV equalizer line onto equalizer fitting nor the TVX
bulb onto the suction vapor line until field supplied suction line is
brazed onto the indoor coil suction line and cooled.
The TXV bulb is to be installed on the suction line near the equalizer
line, using the two bulb clamps furnished with the TXV assembly kit.
The bulb is to make maximum contact. The TXV installation instruc-
tion provide an illustration of proper bulb location.
NOTICE
NOTICE
NOTICE
