MCi Crusader II 1989 Maintenance Manual page 475

Date
1-1-89.
Page · __
1_6_-s _ _
MC-9 MAINTENANCE MANUAL
NOTE: The valve should be held secure in
a padded vise for disassembly.
The valve seat assembly (3) must be replaced in its entirety if
it is damaged or worn.
Remove the eight No. 10-24 fillister head machine screws (15)
used to secure the lower valve body (12) to the upper valve
body (11 ). Carefully separate the two portions by using a
screwdriver at the two pry-lugs on either side of the valve. The
dowel pin (14) will remain in the upper valve body.
The diaphragm valve disc assembly is now removed and the
diaphragm replaced. This is done by removing the locknut (10)
and the diaphragm washer (9). If difficulty is experienced in
removing the locknut, carefully hold the assembly in a vise
between two strips of soft wood.
CAUTION: Do not tighten vise so as to
damage or bend the disc assembly.
The locknut (10) should be torqued to 25-30 inch pounds
(2.8-3.3 Nm) and the valve disc screw (15) is torqued to 12-15
inch pounds (1.3-1.6 Nm).
CLEANING AND INSPECTION
Before reassembling the valve, make sure that all parts are
clean and in good condition. Thoroughly clean the serrations in
1e upper and lower valve bodies.
If the valve seat assembly is defective or leaks more than six
drops per minute at 10 psi (69 kPa) when the coil ls energized,
it should be replaced.
REASSEMBLY
Position the diaphragm disc assembly on the upper valve
body (11) so that the holes in the diaphragm align with the
dowel pin (14) as well as with the pilot-channel hole and the
valve body mounting holes. Set the conical spring (13) on the
locknut (1 O). Carefully place the lower valve body (12) on the
diaphragm disc assembly, engaging the dowel pin (14) with the
hole opposite. Secure the eight No. 10-24 fillister head machine
screws (15). Tighten the screws evenly around the valve body
to 15 in. lbs. (1.6 Nm). Insert the valve seat assembly into the
upper valve body (11) and tighten.
Screw the flux ring assembly (2) into the valve body.
Seat the cover assembly firmly on the flux ring assembly and
tighten.
TESTING VALVE AFTER SERVICING
After servicing, the valve should be tested using water at
approximately170°F ..:t.10° (77°C..:t.6°)andDCvoltageat24VDC.
Apply water at 25 psi (172 kPa) to valve inlet and outlet;
check for external leakage.
Reduce pressure to 1 O psi (69 kPa) and open valve outlet
'heck operation of valve by cycling valve several times.
Check internal leakage (through seat and needle valve) with
1 O psi (69 kPa) at valve in1et and solenoid energized. Maximum
allowable leakage is six drops per minute through the needle
valve and zero leakage through the disc seat
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Figure 16-3. Air Operated Water Valve. Installed
(Effective With Unit 41089).
An air operated type of main heater water valve is used
effective with unit 41089 (figure 16-3).
The bonnet of the valve contains a vane which is con-
nected to a ball in the valve body. The valve is double acting;
air is applied to both open and close the valve. The side of
the vane to which air pressure is applied is controlled by a
separate solenoid valve mounted on the same bracket as
the water valve. The solenoid is activated by signals from
the coach temperature control system which is described
later in this section.
The air operated valve does not require any particular
servicing; however, if for any reason the valve is disas-
sembled, care must be taken in its reassembly so that the
ball is oriented in the correct position in the valve body with
respect to the direction of air flow against the vane. If this is
not done, any signal to the solenoid valve from the tempera-
ture control system will result in the ball in the valve moving
in the opposite direction to what is desired, with a conse-
quent effect on the water flow.
DRIVER'S HEATER WATER
VALVE
DESCRIPTION
The driver's heater control valve is manually operated. It
is located at the left-hand side of driver in heater duct panel
at floor.
Note: Before removal of shut-off valve it is necessary to
close valve in engine compartment This prevents extensive
watN drainage from coolant system.
REMOVAL
1. Remove the valve control handle from the inside of the
coach.
2. Open the exterior service door under the driver's window.
3. Disconnect the heater hose clamps at front and rear of
valve assembly.
Slide hoses away from valve assembly. Remove the two hex
nuts and screws which mount valve assembly Remove
complete valve assembly.