SERVICING
17
To reduce the possibility of external ignition, all open
flame, electrical power, and other heat sources should be
extinguished or turned off prior to servicing a system.
If the following test indicates shorted, grounded or open
windings, see procedure for the next steps to be taken.
Resistance Test
Each compressor is equipped with an internal overload.
The line break internal overload senses both motor
amperage and winding temperature. High motor
temperature or amperage heats the disc causing it to open,
breaking the common circuit within the compressor on
single phase units.
Heat generated within the compressor shell, usually due to
recycling of the motor, high amperage or insufficient gas to
cool the motor, is slow to dissipate. Allow at least three to
four hours for it to cool and reset, then retest.
WARNING
High Voltage!
Disconnect all power before servicing or
installing. Multiple power sources may be present.
Failure to do so may cause property damage,
personal injury or death.
1. Remove the leads from the compressor terminals.
WARNING
See warnings before removing compressor terminal cover.
2. Using an ohmmeter, test continuity between
terminals S-R, C-R, and C-S.
Testing Compressor Windings
If either winding does not test continuous, replace the
compressor.
NOTE: If an open compressor is indicated, allow
ample time for the internal overload to reset before
replacing compressor.
Ground Test
If fuse, circuit breaker, ground fault protective device, etc.
has tripped, this is a strong indication that an electrical
problem exists and must be found and corrected. The
circuit protective device rating must be checked and its
maximum rating should coincide with that marked on the
equipment nameplate.
With the terminal protective cover in place, it is acceptable
to replace the fuse or reset the circuit breaker
ONE TIME
ONLY
to see if it was just a nuisance opening. If it opens
again,
DO NOT
continue to reset.
Disconnect all power to unit, making sure that
all
power legs are open.
1. Carefully remove the compressor terminal protective
cover and inspect for loose leads or insulation breaks
in the lead wires.
2. Disconnect the three leads going to the compressor
terminals at the compressor or nearest point to the
compressor.
3. Check for a ground separately between each of the
three terminals and ground (such as an unpainted
tube on the compressor). If there is any reading of
continuity to ground on the meter, the compressor
should be considered defective.
4. If ground is indicated, replace the compressor.
WARNING
Damage can occur to the glass embedded terminals if the
leads are not properly removed. This can result in terminal
and hot oil discharging.
Compressor Ground Test
