Coleman roof top rv air no cool,warm compressor
Turn the selector switch to “Cool” and the
thermostat to a low temperature (below room temperature).
The fan runs OK, but the unit does not cool. When the unit
housing is removed, we observe that the compressor does not
run; however, it periodically hums for 15 to 30 seconds.
Possible Causes- Check all of this before buying a new unit, that may not be the solution.
“The voltage could be low – ”
a) Check the voltage between #1 on the
overload switch and the “R” terminal of the
compressor while it is not humming. This
voltage must be 115 volts domestic USA
models or 240 volts export/overseas models.
No less than minus 10% is allowable.
b) Check the voltage from “C” or “R” of the
compressor while it is humming (trying to
start). The latter reading will probably be
lower, but it still must be 103.5 volts
minimum domestic USA or 216 volts
minimum export/overseas models.
If the first reading is above 103.5V domestic USA and
the second is under 103.5V domestic USA, there is
too much voltage drop in the lines - a situation which
must be corrected for the air conditioner to perform
safely and satisfactorily.
2. “A capacitor could be shorted, weak or open.”
Turn the power off.
Caution – There is always a chance that a capacitor is
holding a residual charge, so before touching a
terminal, discharge the capacitor as explained earlier
in this booklet.
Remove capacitors, visually examine them and test
them per instructions given in earlier section on
capacitor testing (See page 9).
If the capacitors test OK, replace them and carefully
reconnect the wires. Be sure the wires are connected
to the right terminals.
3. “Start relay contacts could be open – ” if so equipped.
Turn off all power, then check for continuity with
ohm meter between terminals 1 & 2.
4. “Compressor start winding could be open or
Check compressor windings per instructions. See the
section on the compressors (See page 8).
5. “Compressor could be mechanically stuck.”
This very rarely occurs and when it does, it is usually
after a lengthy shutdown. This should be considered
only after all the above possible causes have been
positively eliminated. To free a stuck compressor, use
your hermetic analyzer according to the
Jun 27, 2009 |
Coleman Mach III Air Conditioner