DENSO CORPORATION CLASSIC PLUS 26 - Manual (Page 20)

REFRIGERANT SYSTEM
12
3. Capillary Tube
The capillary tube is a long thin tube and its line
flow resistance serves as an expansion valve. The
length and the inner diameter of the capillary tube
are determined according to the capacity of
refrigeration system, operating conditions and the
amount of refrigerant. The capillary tube causes
the high pressure, high temperature liquid refriger-
ant sent from the condenser to expand rapidly as
the refrigerant is sprayed out through the fixed
orifice in the capillary tube. As a result, the
temperature and state of the refrigerant become
low and mist-like, and therefore it evaporates
easily.
Capillary Tube Dimensions
Qty Purpose of Use I.D. (mm) Length (mm)
1 For cooling
∅
1.5
±
0.05 540
4. Evaporator
The evaporator, like the condenser, is a heat
exchanger covered with spine fins. Heat is
removed from the air being pulled across the
evaporator by the centrifugal fan and the resulting
cool air is expelled through the cooling air ducts.
5. Modulating Tank
The modulating tank consists of a copper pipe
and tank sections, each being separated from the
other. The pipe connects to the evaporator outlet
at one end and to the compressor at the other;
the tank connects to the evaporator inlet. The
modulating tank is covered with insulation to
reduce thermal effects of ambient temperature. It
varies the quantity of refrigerant in the refrigerat-
ing cycle for optimum operating condition; it
stores part of refrigerant under light load and
delivers additional refrigerant to the cycle under
heavy load.
6. High Pressure Switch
The high pressure switch prevents the condenser
and compressor from being damaged by exces-
sively high pressure in the high pressure line of the
refrigeration cycle. The switch is normally closed.
The snap disk responds to variations in pressure
and, if pressure is abnormally high, the snap disk
moves down to push the pin down, causing the
internal contacts to open. This interrupts the
ground signal at the Control Board (J104 connec-
tor) which turns the compressor off.
Possible causes of this trouble include:
A. The condenser air filter is dirty, restricting air
flow.
B) The condenser blower is defective.
Capillary Tube
Modulating Tank
High Pressure Switch