MCi Crusader II 1989 Maintenance Manual page 489

Date 1-1-89
Page __
1_6-_19 _ _
MC-9 MAINTENANCE MANUAL
3. Remove the two capscrews holding the power assem-
bly to the valve body flange. Lift off the power assembly and .
remove the cage assembly.
4. Thoroughly clean all parts with mineral spirits and stiff
bristle (not steel) brush. Dry thoroughly with compressed
air.
CAUTION: Do not
use
gasoline, nephtha,
carbon tetrachloride or slmilar solvent to
clean parts. Do not use steam or caustic
materials for cleaning.
5. Inspect all parts for wear, pitting, scoring, cracks or
distortion. Remote bulb and connecting tube must be free
of cracks, holes, kinks and cuts.
When reassembling, replace with new gaskets in proper
place. Be sure the two lugs on the cage assembly fit into
grooves provided in the power assembly. Do not force the
valve together. The cage must fit properly before tightening
the body flange. Tighten bolts evenly.
CAUTION: If necessary to make a sol-
dered connection, flrat remove the power
and cage assemblles and all gaskets.
Keep heat away from all parts except the
-body flange, partlcularly the remote con-
trol bulb and tube.
SOLDERING -Before soldering any part of the system,
make sure the area is well ventilated. Use (Stay-Clean) flux
·sparingly and apply solder (95-5 round wire ¼" (3.1 mm)).
After completing repairs, test for leaks.
When using heat at or near a valve, wrap with a water-
saturated rag to prevent overheating of vital parts.
EXPANSION VALVE TROUBLESHOOTING
TROUBLE
LOW SUCTION PRESSURE, HIGH SUPERHEAT
Expansion valve limiting flow or adjustment too
low.
,let pressure too low from excessive vertical lift,
Jndersize liquid line or excessive low condens-
• ing temperature. Resulting pressure difference across
valve too small.
Gas in liquid line due to pressure drop in the line
or insufficient refrigerant charge.
Inlet pressure too low from excessive vertical lift,
undersize liquid line or excessive low condens-
ing temperature. Resulting pressure difference across
valve too small.
Gas in liquid line t!ue to pressure drop in the line
or insufficient refrigerant charge.
Valve orifice too small.
Superheat adjustment too high.
Power assembly failure or partial loss of charge.
Air filter screen clogged.
King valve at liquid receiver too small or not fully
opened. Hand valve stem failure or valve too
,iall or not fully opened.
Plugged lines.
Liquid line too small.
CAUSE
Adjust and/or test expansion valve.
1. Increase head pressure.
2. If liquid line is too small, replace with proper size.
Locate cause of liquid line flash and correct by use of the
following methods: (1) Add charge (2) Replace or clean filter
dryer.
1. Increase head pressure.
2. If liquid line is too small, replace with proper size.
Locate cause of liquid line flash and correct by use of the
following methods (1) Add charge (2) Replace or clean filter
dryer (3) Check for proper line size.
Replace with proper valve.
Adjust superheat as outlined under Superheat Adjustment.
Replace power assembly or replace valve.
Clean or replace air filter screen.
1. Discharge or suction service valve on compressor restricted
or not fully opened.
2. Repair or replace faulty valve if it cannot be fully opened.
3. Replace any underside valve with one of correct size.
Clean, repair or replace lines.
Install proper size liquid line.