MovinCool 24HFU Service Manual - Manual (Page 10)

MOVINCOOL 24HFU / 24HFU-1 SERVICE PAGE 10
REFRIGERANT SYSTEM
3-3. 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 capil-
lary 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 refrigerant 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
Capillary Tube Dimensions
Qty Purpose of Use I.D. (mm) Length (mm)
1 For cooling
∅
1.5
±
0.05 540
3-4. 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.
3-5. 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 refriger-
ating cycle for optimum operating condition; it
stores part of refrigerant under light load and
delivers additional refrigerant to the cycle under
heavy load.
■ Modulating Tank
3-6. High Pressure Switch
The high pressure switch prevents the con-
denser and compressor from being damaged by
excessively 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 abnor-
mally high, the snap disk moves down to push
the pin down, causing the internal contacts to
open. This generates a signal to open the
auxiliary relay.
Possible causes of this trouble include:
(1) The condenser air filter is dirty, restricting
air flow.
(2) The condenser blower is defective.
■ High Pressure Switch