Checking Compressor; S-17A Resistance Check; S-17B Ground Test - Amana AVZC18 Series Service Instructions Manual

SERVICING
S-17 CHECKING COMPRESSOR
WARNING
Hermetic compressor electrical terminal venting can
be dangerous. When insulating material which
supports a hermetic compressor or electrical terminal
suddenly disintegrates due to physical abuse or as a
result of an electrical short between the terminal and
the compressor housing, the terminal may be
expelled, venting the vapor and liquid contents of the
compressor housing and system.
If the compressor terminal PROTECTIVE COVER and gasket (if re-
quired) are not properly in place and secured, there is a remote
possibility if a terminal vents, that the vaporous and liquid dis-
charge can be ignited, spouting flames several feet, causing po-
tentially 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 im-
pinges 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 pres-
ence 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, elec-
trical power, and other heat sources should be extinguished or
turned off prior to servicing a system.
S-17A RESISTANCE TEST
Inverter on the outdoor control board takes the position signal
from UVW line connected with compressor. When the system de-
tects the malfunction on the compressor, check the insulation
resistance in accordance with the following procedure.
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.
See warnings S-17 before removing compressor
terminal cover.
2. Check the wiring connection of UVW on compressor terminal.
3. Check the insulation resistance of compressor between the
compressor terminal and unpainted refrigerant piping.
Unpainted
Refrigerant
Piping
OHMMETER
TESTING COMPRESSOR WINDINGS
If the insulation resistance of compressor is less than 100 k Ohms,
replace the compressor.

S-17B 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 con-
tinue to reset.
Disconnect all power to unit, making sure that all power legs are
open.
1. DO NOT remove protective terminal cover. Disconnect the
three leads going to the compressor terminals 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 unpainted 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 compressor
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.
Compressor
Terminal
37