IOM 1206-1
65
Unit Maintenance
Unit Maintenance
General
On initial start-up and periodically during operation, it will be
necessary to perform certain routine service checks. Among
these are checking the liquid line sight glasses, taking
condensing and suction pressure readings, and checking to see
that the unit has normal superheat and subcooling readings. A
recommended maintenance schedule is located at the end of
this section.
Compressor Maintenance
The scroll compressors are fully hermetic and require no
maintenance other than checking oil level.
Lubrication
No routine lubrication is required on AGZ units. The fan
motor bearings are permanently lubricated and no further
lubrication is required. Excessive fan motor bearing noise is an
indication of a potential bearing failure.
POE type oil is used for compressor lubrication.
ARNING
Further details are listed in the Unit Service section starting on
page 69
.
Electrical Terminals
All-Aluminum Condenser Coils
The condenser coils are an all-aluminum design including the
connections, micro-channels, fins (an oven brazing process
brazes the fins to the micro-channel flat tube), and headers
(
Figure 24
), which eliminates the possibility of corrosion
normally found between dissimilar metals of standard coils.
During the condensing process, refrigerant in the coil passes
through the micro-channel flat tubes, resulting in higher
efficiency heat transfer from the refrigerant to the airstream.
In the unlikely occurence of a coil leak, contact Daikin
Applied to receive a replacement coil module.
Figure 24: Micro-Channel Coil Cross Section
Connecting the Condenser Coil to Copper
Tubing
Figure 25
shows the aluminum condenser coil connection to
the copper tubing in the unit. Because of the low melting
point
of aluminum (1220°F compared to 1984°F for copper), this
brazed joint is performed with a low temperature brazing
process.
WARNING
POE oil must be handled carefully using proper protective
equipment (gloves, eye protection, etc.) The oil must not come
in contact with certain polymers (e.g. PVC), as it may absorb
moisture from this material. Also, do not use oil or refrigerant
additives in the system.
DANGER
Electric shock hazard. Turn off all power before
continuing with following service.
!
CAUTION
Potential equipment damage. If a standard copper
brazing process is performed at this joint, the process will
damage the aluminum connection. If a condenser coil
ever needs to be replaced, the copper aluminum joint
repair should be done with a ProBraze™ repair kit
manufactured by OmniTechnologies Corporation. A
non-corrosive flux must also be used. The brazing
temperature should be between 850°F–900°F
.
If a coil
needs replacing, contact Daikin Applied for a coil and
copper connection assembly
.
!