Compu-aire CAG-30 Series, Installation And Operation Manual, Page: 39 / 48

39
18 TROUBLESHOOTING GUIDE
Complaint Problem Symptom Action
1. System does not run. No 24VAC supply
voltage.
Power LED is not on.
Check circuit breaker in
system 24VAC circuit
and reset if necessary.
Check System cutout
switch. Test for 24VAC
at pins 1 and 2 of MCP.
If no voltage check
machine wiring. Other-
wise, if voltage replaces
MCP.
System is not turned on.
Power LED is on but,
System LED is off.
Press the On button on
the MCP. If the system
does not start and the
display is blank, replace
the MCP.
Bad or locked up MCP.
Display is blank, shows
erroneous characters or
does not change
messages.
Press Off button on
MCP then press On
button. If the system
does not start or if the
display still shows
erroneous information,
replace the MCP.
Complaint Problem Symptom Action
2. Nothing is visible on
the display or is barely
visible.
Display contrast is
adjusted too low.
Power is on and system
is running okay. But,
nothing is visible or is
barely visible on display.
Refer to the section
MCP Circuit
Adjustments, in this
guide. Adjust display
contrast for best
visibility. The display will
not be visible unless
light is directed into it (it
does not have its own
light source).
3. Temperature or
humidity displayed is
wrong.
Sensor circuits are out
of calibration.
Displayed value(s) are
wrong by a few
increments.
If the value is wrong by
a few degrees or
percent when
compared to an
accurate measuring
instrument, then try