Checking Compressor; Testing Compressor Windings; S-17A Resistance Test; S-17B Ground Test - Daikin ComfortNet DX16TC Series Service Instructions Manual
Condensing units, split system heat pumps with r-410a refrigerant blowers, coils, & accessories
Hide thumbs
Also See for ComfortNet DX16TC Series:
- Service instructions manual (93 pages) ,
- Service instructions manual (122 pages)
Table of Contents
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 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 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,
electrical power, and other heat sources should be extin-
guished or turned off prior to servicing a system.
If the following test indicates shorted, grounded or open wind-
ings, see procedures S-19 for the next steps to be taken.
S-17A 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 amper-
age 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 re-
cycling 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.
Fuse, circuit breaker, ground fault protective device, etc. has
not tripped -
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. Using an ohmmeter, test continuity between terminals S-R,
C-R, and C-S, on single phase units.
OHMMETER
TESTING COMPRESSOR WINDINGS
If either winding does not test continuous, replace the com-
pressor.
NOTE: If an open compressor is indicated, allow ample time
for the internal overload to reset before replacing 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
continue to reset.
A Meghometer should not be used to determine good or bad
compressors. There is not an industry recognized specification
for mega ohm values for small tonnage compressors. Scroll
compressors can have the motor winding end-turns in the oil,
which can produce a lower resistance reading to ground. The
insulation type is the same for scroll and reciprocating com-
pressors.
Disconnect all power to unit, making sure that all power legs
are open.
79
C
R
S
COMP
- Quick Links:
- Troubleshooting Chart
Hide quick links:
Table of Contents
Troubleshooting
