507607-03
Issue 1827
Page 9 of 23
Figure 11.
An R410A system will not operate properly with an R-22
metering device.
Install the refrigerant metering device as shown in Figure
11. Do not twist cap tubes when loosening the seal nut from
the orifice housing. Use wrench to back up the distributor.
Expansion Valve Systems
Expansion valves equipped with Chatleff-type fittings are
available from the manufacturer. See Table 3 for proper
TXV for each unit.
Model
Part Number
4SCU16LS-24-36
A4TXV01
4SCU16LS-48
A4TXV02
4SCU16LS-60
A4TXV02
Table 3. TXV Data
To install an expansion valve (Figure 11):
1. Separate the distributor assembly and remove the
piston orifice and used Teflon seal. Insert nozzle end
of the expansion valve along with a new Teflon seal
into the distributor and tighten to 20 - 30 ft. lbs. Use
backup wrench on all wrench flats. Overtightening will
crush the Teflon seal and may cause a leak.
2. Attach liquid line portion of distributor assembly along
with new Teflon seal to the inlet of the expansion valve.
Tighten to 20 - 30 ft. lbs. Use backup wrench on all
wrench flats. Overtightening will crush the Teflon seal
and may cause a leak.
3. Connect the external equalizer line to the equalizer
port on the suction line and tighten to 8 ft. lbs.
4. Strap the superheat sensing bulb to the suction header.
If installing an expansion valve on an indoor coil that
previously used a fixed orifice, be sure to remove the
existing fixed orifice. Failure to remove a fixed orifice when
installing an expansion valve to the indoor coil will result in
improper operation and damage to the system.
Manifold Gauge Set
Manifold gauge sets used with systems charged with
R410A refrigerant must be capable of handling the higher
system operating pressures. The gauges should be rated
for use with pressures 1 - 800 on the high side and a low
side of 30” vacuum to 250 psi with dampened speed to 500
psi. Gauge hoses must be rated for use at up to 800 psi of
pressure with a 4000 psi burst rating.
Liquid and Suction Line Service Valves
The liquid line and suction line service valves (Figure 12)
and service ports are used for leak testing, evacuation,
charging, and checking charge.
Each valve is equipped with a service port which has a
factory-installed Schrader valve. A service port cap protects
the Schrader valve from contamination and serves as the
primary leak seal.
To Access the Schrader Port:
1. Remove the service port cap with an adjustable
wrench.
2. Connect gauge to the service port.
3. When testing is completed, replace service port cap.
Tighten finger tight, then an additional 1/6 turn.
To Open Liquid or Suction Line Service Valve:
1. Remove stem cap with an adjustable wrench.
2. Use service wrench with a hex-head extension to back
the stem out counterclockwise as far as it will go. Use a
3/16” hex head extension for liquid line service valves
and a 5/16” extension for suction line service valves.
3.
Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.
To Close Liquid or 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
firmly.
3. An R410A system will not operate properly with an
R-22 metering device.
Suction Line (Ball Type) Service Valve
Suction line (ball type) service valves function the same
way as the other valves; the difference is in the construction
The ball valve is equipped with a service port with a factory-
installed Schrader valve. A service port cap protects the
Schrader valve from contamination and serves as the
primary seal.
