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12.11.2 - EXV troubleshooting procedure
Follow steps below to diagnose and correct EXV problems.
Check EXV motor operation rst (see procedure in the 30GX/
HXC Pro-Dialog Plus Controls IOM). You should be able to feel
the actuator moving by placing your hand on the EXV. You should
feel a hard knocking come from the actuator when it reaches the
top of its stroke (can be heard if surroundings are relatively quiet).
The actuator should knock when it reaches the bottom of its stroke.
If it is believed that the valve is not working properly, contact
your Carrier service department for further checks on:
• output signals on EXV module
• wire connections (continuity and tight connection at all pin
terminals)
• resistance of the EXV motor windings.
All metallic parts of the unit (chassis, casing panels, control boxes,
heat exchangers etc.) are protected against corrosion by a coating
of powder or liquid paint. To prevent the risk of blistering
corrosion that can appear when moisture penetrates under the
protective coatings, it is necessary to carry out periodic checks
of the coating (paint) condition.
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