Chapter 19 Installation and Troubleshooting of Domestic Refrigerators and Freezers
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Pinpointing a Restriction
Use the following procedure to determine
whether the problem is a result of a clogged fi lter-
drier or a clogged capillary tube:
1. Recover the refrigerant.
2. Clean the connection between the fi lter-drier
and the capillary tube. Flux it, heat it, and sep-
arate the capillary tube from the fi lter-drier.
The system can now be checked to fi nd out if
either the fi lter-drier or the capillary tube is
clogged.
3. To fi nd which component is at fault, hook up
a nitrogen cylinder as shown in Figure 19-30.
4. Open the nitrogen cylinder valve, the mani-
fold gauge valves, and the piercing valves. If
the fi lter-drier is open, nitrogen will come out
of its open end. If the capillary tube is open,
Pinp p p p
a small fl ow (because the tube is small) will
come out its opening. If either one is clogged,
there will be no fl ow through it.
Clogged filter-driers must be replaced. Sometimes
clogged capillary tubes can be opened with a high-
pressure hydraulic pump. Repair and replacement pro-
cedures are presented in Chapter 20, Service and Repair
of Domestic Refrigerators and Freezers.
Pro Tip
Filter-Drier ReplacementlacementpRe
The fi lter-drier should be replaced any time the
system is opened, regardless of whether the fi lter-drier
is the point of restriction or not.
Post-Condenser (PC) Loop Problems
In the previous chapter, it was pointed out that
some domestic refrigerator-freezers are equipped with
Filter-Drier
T he fi lter-drier should be replaced any time the
system is opened, regardless o f whether the fi lter-drier
is the p oint of restriction or not .
Compressor Gauge
manifold
Condenser
Nitrogen
cylinder
B
E
F
G
D
C
A
Evaporator
Piercing valve
on suction line
Piercing valve
on liquid line
Capillary tube
Filter-drier
Nitrogen
Goodheart-Willcox Publisher
Figure 19-30. To check whether the capillary tube or the fi lter-drier is clogged, separate the capillary tube from the fi lter-drier. Charge
some nitrogen into the system by opening valves A, B, C, D, and E and then check the fl ow at F and G.