PREVOST LE MIRAGE XLII BUS SHELLS, Руководство по обслуживанию

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Section 22: HEATING AND AIR CONDITIONING
PA1564
43
FIGURE 47: PNEUMATIC WATER VALVE
22241
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Valve Troubleshooting
PROBLEM PROCEDURE
Valve fails to
close. 1. Check electrical supply
with a voltmeter. It
should agree with
nameplate rating.
2. Check pressure at pilot
solenoid valve inlet. It
must be at least equal
to the minimum
pressure stamped on
the nameplate. It
should not go below
minimum while valve is
operating.
Valve fails to open. 1. Check that the closure
member assembly,
and that main actuator
and cylinder springs
are free to travel.
2. Check that there is no
restriction to the air
escaping from the
actuator casing.
3. Make sure that pilot
solenoid valve
operates properly.
11.1.6 Central Hot Water Pneumatic Valve
Assembly
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Description
The flow of hot water to the vehicle's central
heater core is controlled by a 3-way pneumatic
water valve assembly. The valve, located in the
evaporator compartment, is designed so that the
pilot solenoid valve, which is part of the
assembly, opens and closes a port which directs
air pressure to the actuator casing, thereby
allowing the hot water to enter the main heater
core or bypassing it.
When the vehicle is operating with no current to
the pilot solenoid valve, no air pressure is
admitted to the actuator casing, the cylinder
spring pushes up against the cylinder, thereby
allowing the hot water to enter the main heater
core.
The central heater water valve requires a
minimum amount of maintenance. The valve
should be free of dirt sediment that might
interfere with its operation. No other
maintenance is needed unless a malfunction
occurs.
FIGURE 48: CENTRAL HOT WATER PNEUMATIC VALVE
ASSEMBLY
22240