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

Page 11 of 38

DESCRIPTION-Air Conditioner (Manual)
Refrigerant Leak Wai
,---Saturated liquid line
Super heat
-10 P=1010kPa
I1 03 kg/cm2, 14 6 si1 mnsant (141
U 4- Super heated vapor
P = 39 2 kPa 10 40 kglcm', 5 7 pal mmtant (-221
2 -40
P Saturated vapor line
5 40 + (-581
40 1, k;xture; 1 , (-761 liquid and vapor
-70
(-9410 02 04 06 08 10 12 1321 (641 (9 61 (12 81 (16 01 (1921
Volume m3/kg (cu ftilb)
Relation between temperature and volume
(Refrigerant R-121
SHA2398
Definition
The super heat is the difference between the tem-
perature of an optional super heated vapor point
and the saturated temperature point (which
is
located on the saturated vapor line) under the same
pressure
as for the former point
SUPER HEAT SWITCH
The super heat switch, placed, in the refrigerant
line
at the outlet of the evaporator, consists of a
diaphragm. temperature sensor, moving contact
(A) and fixed contact (B) The diaphragm detects
the refrigerant line pressure and the temperature
sensor senses the refrigerant line temperature.
ing System (Cont'd)
When the temperature in the refrigerant line in-
creases, the
gas charged inside the temperature
sensor expands This causes
a force to move the
diaphragm upward against
the refrigerant line pres-
sure When
the difference between the saturated
temperature and the detected temperature
in rela-
tion to the detected pressure reaches
a specified
condition, the adjusting screw
is pushed up by the
diaphragm This then causes moving contact point
(A) to move down so that the super heat switch
turns
"ON"
0
vmg COntaCt
I . ,I
$(& Temperature sensor & (R-12 within b~ capillary rubel
SHA2298
SUPER HEAT TIMER
During rapid acceleration, the "super heat" in-
creases momentarily and returns to
its original level
quickly even when the amount of the refrigerant
is
normal. Because of this, a timer, used in the warn-
ing system, detects an increase
in "super heat"
only when the amount of refrigerant
is low, there-
by preventing erroneous alarms
HA-I 1