SERVICING
11
If the compressor terminal PROTECTIVE COVER and
gasket (if required) are not properly in place and secured,
there is a remote possibility if a terminal vents, that the
vaporous and liquid discharge can be ignited, spouting
flames several feet, causing potentially severe or fatal injury
to anyone in its path.
This discharge can be ignited external to the compressor if
the terminal cover is not properly in place and if the
discharge impinges on a sufficient heat source.
Ignition of the discharge can also occur at the venting
terminal or inside the compressor, if there is sufficient
contaminant air present in the system and an electrical arc
occurs as the terminal vents.
Ignition cannot occur at the venting terminal without the
presence of contaminant air, and cannot occur externally
from the venting terminal without the presence of an
external ignition source.
Therefore, proper evacuation of a hermetic system is
essential at the time of manufacture and during servicing.
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.
COMPRESSOR WINDING INSULATION TEST
The Inverter on the outdoor control board takes the position
signal from the UVW line, connected with the compressor.
If the system detects a malfunction on the compressor,
check the insulation resistance in accordance with the fol-
lowing procedure.
WARNING
HIGH VOLTAGE
Disconnect ALL power before servicing or in-
stalling this unit. Multiple power sources may
be present. Failure to do so may cause proper-
ty damage, personal injury or death.
1. Remove the leads from the compressor terminals.
WARNING
See warnings before removing compressor terminal cover.
2. Using a Megometer, attach one lead to ground.
3. Using the other lead of the Megometer, check the
insula tion between U to ground, V to ground, W to
ground.
Compressor
Terminal
Unpainted
Refrigerant
Piping
TESTING COMPRESSOR WINDINGS INSULATION
NOTE:
The 2, 3, and 4 ton compressor has a terminal on
the top. The 5 ton compressor has the terminals on the
side. If the insulation resistance of the compressor is less
than 100k Ohms between U to ground, V to ground, W to
ground, replace the 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. DO NOT remove protective terminal cover. Discon-
nect the three leads going to the compressor termi-
nals at the nearest point to the compressor.
2. Identify the leads and using an ohmmeter on the R x
10,000 scale or the highest resistance scale on your
ohmmeter check the resistance between each of the
three leads separately to ground (such as an unpaint-
ed tube on the compressor).
3. If a ground is indicated, then carefully remove the
compressor terminal protective cover and inspect for
loose leads or insulation breaks in the lead wires.
4. If no visual problems indicated, carefully remove the
leads at the compressor terminals.
5. Carefully retest for ground, directly between compres-
sor terminals and ground.
6. If ground is indicated, replace the compressor. The
resistance reading should be infinity. If there is any
reading on meter, there is some continuity to ground
and compressor should be considered defective.
