4-12
©
2015 Mobile Climate Control
T-367 Rev. 05/2015
switch should close, (continuity) within required
cut in tolerance.
f. For a low pressure switch, close cylinder valve and
bleed-off valve. Open cylinder valve to bring pres
sure above the cutout setting. Close the cylinder
valve and slowly open bleed-off valve. The switch
should open, (no continuity) within required cut
out tolerance. Open cylinder valve and increase
pressure by closing the bleed-off valve. As pres
sure increases, switch should close, (continuity)
within required cut in tolerance.
g. Replace or re-install switch (as required) and re
connect wiring.
4.10 FILTER-DRIER
4.10.1 To Check Filter-Drier
The filter-drier (see Figure 4-9) must be changed if
the drier is partially restricted or service has been
performed on the refrigerant system. Check for a
restriction by feeling the inlet and outlet lines of the
filter-drier. If the outlet side feels cooler than the
inlet side, then the filter-drier should be changed.
1
5
4
3
2
3
1. Filter--Drier Inlet Service Valve
2. Valve Service Port
3. Hex Nut
4. Filter--Drier
5. Filter--Drier Outlet Service Valve
Figure 4-9 Filter-Drier Removal
4.10.2 To Replace Filter-Drier
WARNING
Use of an electro-magnetic valve as a
means of positive shutoff for service is
not recommended for safety, or good ser
vice practice.
a. Perform a system low side pump down. Refer to
paragraph 4.4.2.
b. Front seat the filter drier outlet valve to isolate fil
ter drier.
c. Lock out/Tag out the bus electrical system to pre
vent unit operation.
d. Using wrenches to back up the service valves,
slowly loosen hex nuts retaining the filter drier.
WARNING
The filter-drier may contain liquid refrig
erant. Slowly loosen the ORS hex nuts to
avoid refrigerant contact with exposed
skin or eyes.
e. Place a new filter-drier near the unit for immediate
installation.
f. Loosen or remove clamps securing the filter-drier.
g. Remove the filter-drier.
h. Remove seal caps from the new filter-drier. Apply
a light coat of mineral oil to the O-Rings and seat in
the grooves of the filter-drier.
i. Assemble the new filter-drier to lines ensuring that
the arrow on the body of the filter-drier points in
the direction of the refrigerant flow (refrigerant
flows from the condenser to the evaporator), and
that the O-Rings have remained in place. Finger
tighten ORS hex nuts.
j. Tighten the filter-drier ORS hex nuts using two
open end wrenches.
k. Leak check filter drier connections with nitrogen
by adding through filter drier service valve ports.
l. Remove nitrogen and evacuate filter drier using fil
ter drier service ports.
m.Open filter drier service ports and restore electric
al power to unit.
4.11 SERVICING THE LIQUID LINE SERVICE VALVE
The Liquid line solenoid valve (Figure 4-10) requires
no maintenance unless a malfunction to the internal
parts or coil occurs. This may be caused by foreign
material such as: dirt, scale, or sludge in the
refrigeration system, or improper voltage to the coil.
There are only three possible valve malfunctions: coil
burnout, failure to open, or failure to close.
Coil burnout may be caused by the following:
1 Improper voltage.
2 Continuous over-voltage, more than 10% or un
der-voltage of more than 15%.