engine NISSAN 300ZX 1984 Z31 Heather And Air Conditioner Workshop Manual

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Pages: 38, PDF Size: 1.15 MB

Page 10 of 38

NISSAN 300ZX 1984 Z31 Heather And Air Conditioner Workshop Manual DESCRIPTION-Air Conditioner (Manual)
Refrigerant Leak Warning System
The refrigerant leak warning system, used in con-
junction with the low-pressure switch, protects the
cooler cycle fro

DESCRIPTION-Air Conditioner (Manual)
Refrigerant Leak Warning System
The refrigerant leak warning system, used in con-
junction with the low-pressure switch, protects the
cooler cycle from damage due to continued opera-
tion of the
air conditioning system when there is a
shortage of refrigerant
It also indicates when to re-
plenish the refrigerant
Refrigerant leak
warnmg lamp Recirculation switch
Air conditioner switch
control lever
SHA227B
I ll I
SHA2286
When the refrigerant in the cooler cycle is insuffi-
cient,
it vaporizes quickly inside the evaporator As
a result, the "super heat" of the refrigerant at the
outlet of the evaporator increases
If it exceeds the
specified level [Approximately 45°C
(8l0F)1, the
super heat switch turns on, allowing the current to
flow through the timer If current continues to
flow through the timer for the specified length of
time, the timer activates to close the contacts
which turn on the warning lamp
Leak warning lamp check
Conduct a continuity test in the leak warning lamp
circuit.
1) Turn ignition switch "ON" (with engine off) to
make sure warning lamp illuminates.
2) Start engine. Warning lamp should go out if the
amount of refrigerant
is sufficient.
EXPLANATION OF SUPER HEAT
When a liquid under constant pressure inside a
cylinder is heated, it apparently changes in three
different
states The relationship between the tem-
perature of the liquid (refrigerant) and
its volume,
which
uses the pressure as a parameter, is shown in
the graph below.
1) The temperature of the liquid rises along the
saturated liquid line (a -+ b or a + b')
2) When the temperature of the liquid reaches a
certain level, evaporating bubbles quickly ap-
pear This mixture of liquid and vapor contin-
ues to take place, during which the tempera-
ture remains constant until the
last droplet of
liquid vaporizes. Points c and c' where the
entire liquid vaporizes, are located on the
saturated vapor line (b
+ c or b -+ c').
3) When the liquid is further heated, the tempera-
ture of the vapor
rises again and its volume also
increases.
The volume will continue to increase
as the temperature is increased
We call this vapor "super heated vapor" (c + d
or c'
+ d')
The line between points c and c'
is called the
"saturated vapor line."
HA-I 0