A. Factory-Installed Expansion Valves
The sensing bulb must be installed to the vapor line
during the field installation. Skip to step 3 below for factory-
installed expansion valves.
B. Field-Installed Expansion Valves
1. Disassemble the flow rater body and remove the
piston from the distributor. Be sure to save the
O-ring in the tail piece.
2. Install the expansion valve between the tail piece
and the distributor as shown in Figure 2. Be sure to install
the O-rings as shown in Figure 2.
3. The bulb and capillary tubing should be routed outside of
the coils’ casing, making sure the capillary tube will not be
directly against sharp casing edges. The bulb should be
installed after the vapor and liquid line is soldered and
leak checked to prevent subjecting the bulb to excessive
heat. To assure accurate sensing and the best
performance, the bulb should be placed on the upper half
of the vapor line at the two or ten o’clock position and at
least 6" from the coil manifold as shown in Figure 2.
4. Attach the bulb securely with the copper strap provided.
5. Insulate the bulb thoroughly with a suitable insulation
material such as cork tape.
Figure 2
The indoor piston may require changing to match the outdoor unit.
The correct indoor piston is shipped with each outdoor unit. Each
coil has a marker strip, marked with the size of the factory-installed
piston located on the coil liquid line. Compare this piston marking
with the chart on page 8. If they are different, change the piston to
the correct size as shown in Figure 1.
The piston is located in the distributor fitting on the liquid line.
To change the piston, remove stub tube nut (left-hand thread) and
separate the liquid line from the distributor, then the piston. Install
the correct piston with the rounded end toward the distributor.
Reinstall the O-ring and stub nut (do not nick or handle the O-ring).
NOTE:
ON PRECHARGED COIL, THE REFRIGERANT WILL
HAVE TO BE REMOVED PRIOR TO CHANGING THE PISTON.
Figure 1
11
FIXED PISTON TYPE RESTRICTORS
EXPANSION VALVES
REFRIGERANT METERING DEVICES
NOTE:
The indoor expansion device size and type are located on the outdoor unit’s series and rating plate.
