Temperatures & Pressures Chart; Leak Testing - PREVOST H3-41 Maintenance Manual

5.8 TEMPERATURES & PRESSURES
CHART
R134a VAPOR-PRESSURE
TEMPERATURE
°F °C
-100 -73.3
-90 -67.8
-80 -62.2
-70 -56.7
-60 -51.1
-50 -45.6
-40 -40.0
-30 -34.4
-20 -29
-10 -23
0 -18
10 -12
20 -7
30 -1
40 4
50 10
60 16
70 21.1
80 27
90 32.2
100 38
110 43.3
120 49
130 54.4
140 60
150 65.6
160 71
170 76.7
180 82.2
190 87.8
200 93.3
210 98.9
PRESSURE
psi kPa
27.8 191.7
26.9 185.5
25.6 176.5
23.8 164.1
21.5 148.2
18.5 127.6
14.7 101.4
9.8 67.6
3.8 26.2
1.8 12.4
6.3 43.4
11.6 80
18.0 124.1
25.6 176.5
34.5 237.9
44.9 309.6
56.9 392.3
70.7 487.5
86.4 595.7
104.2 718.5
124.3 857.0
146.8 1012.2
171.9 1185.3
199.8 1377.6
230.5 1589.3
264.4 1823.0
301.5 2078.8
342.0 2358.1
385.9 2660.8
433.6 2989.7
485.0 3344.1
540.3 3725.4
PA1621 Maintenance Manual All Series | Revised February 2019
SECTION 22: HEATING AND AIR CONDITIONING
5.9

LEAK TESTING

Some methods such as nitrogen pressure and
soap, and electronic sniffer can be used for leak
testing. However, the most common method
used is a "Halide" torch consisting of an
acetylene tank, a burner and a suction test hose.
Proceed as follows:
DANGER
Do not inhale fumes from leak detector.
The flow of acetylene to the burner causes a
depression in the test line. Any gas refrigerant
present will be drawn through the hose and into
the burner where it decomposes into free acids.
These acids come in contact with the hot copper
reaction plate in the burner, causing color
reaction in the flame. A small concentration is
indicated by a
concentration by an intense blue. Do not
confuse this change in color with the change
caused by shutting off the air supply through the
hose by holding the end too close to an object.
The procedure for testing is:
1. Adjust flame so that the top of the cone is
approximately level or within one-half inch
above the plate.
2. Probe end of suction test tube around all
joints, valves, etc. When a leak has been
found at a soldered joint, this specific
section of the system must be pumped
down. Do not solder as pressure will force
hot solder out. If the system is empty, it is
more economical to put in just enough R-
134a to produce about 15 psi (103 kPa).
The pressure can be raised to about 150 psi
(1034 kPa) with dry nitrogen.
NOTE
This gas is put into the suction and discharge
shutoff valves at the compressor. The receiver
valves must be opened. If no leaks are found,
recover this mixture, evacuate the system and
fill with refrigerant.
6. CENTRAL HVAC SYSTEM
The passenger's unit evaporator fan, located in
the evaporator compartment on the L.H. side of
vehicle is protected by circuit breaker CB3 (CB6
on X3 VIP), 90 amp with manual-reset mounted
green tint and a
53
large