PREVOST X3-45 COMMUTER, Руководство по обслуживанию

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SECTION 22: HEATING AND AIR CONDITIONING
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version – Rev.2 April 2016) 23
FIGURE 23: MOISTURE INDICATOR SIGHT GLASS
3- At fast idle, the high side pressure should
be near the following calculation: add 30° F
to the ambient temperature in Fahrenheit.
In the refrigerant chart (see 7.13
Temperatures & Pressure), find this
temperature and the corresponding
saturation pressure and add 10 psi for the
pressure drop between compressor and
condenser.
Calculation example:
At 70°F outside, add 30°F. In the chart
(paragraph 7.13 ), find the pressure value for
a temperature of 100°F. For 134a refrigerant
gas, you will find a value of 124 psi. Add 10
psi to this value for the compressor to
condenser line, this result gives 134 psi. So a
high side pressure value between 129 to 139
psi should be OK.
6.6.2 Refrigerant addition
NOTE
Use a bottle that is more than half full.
Always charge the system with the cylinder
upright and the valve on top to avoid drawing
liquid out of the cylinder.
1. Install a heated refrigerant bottle at the
back of the vehicle, on a scale, straight up.
Refer to section “Precautions in Handling
Refrigerant” for the proper heating method.
2. Connect the yellow hose of your manifold
gage set to the red (vapor) valve on the
bottle. Connect the blue valve of the gage
set on the suction shut-off valve service
port of the compressor. Connect the red
valve of the gage set to the discharge shut-
off valve service port. Hoses should be
purged of air at installation (evacuated).
WARNING
Secure manifold gage hoses so they will not
be damaged by engine belts and pulley.
3. Midseat the compressor suction and
discharge shut-off valves.
4. In order to speed up the charging, unplug
the unloader to keep all compressor
cylinders active.
CAUTION
When unplugging the unloader, use
exceptional caution so as not to rotate the
blue unloader solenoid coil on the Bitzer
compressor R.H. cylinder. The aluminum
cap on top of the coil may become loose; it
can result in failure of the unloader
stem/valve (FIGURE 30).
Make sure the aluminum cap on top of the
blue unloader coil remains tight.
5. Let the door and hatches open and maybe
open side windows to prevent cooling down
the coach too rapidly. Preferably, the
interior would be hot, at least over 68°F.
WARNING
If discharge pressure is above 138 psig, the
condenser fans will be running. Keep hands
clear of fans
6. Start engine.
7. Switch to fast idle for faster fill and battery
protection.
8. Open the blue gage valve. The suction
pressure should go up meaning the
compressor is sucking from the tank also. If
there is almost no pressure rise, the tank is
too low or too cold.
9. Check the moisture indicator sight glass
and the discharge pressure to meet the
criteria described above.
10. When the sight glass gets clear, you can
add some reserve, up to 2 pounds, as long
as the high pressure does not move up.
11. When finished, close gage valves and
bottle valve.
12. Before stopping the engine, check the
compressor oil level and note it in the repair