Specifications

87
JOHNSON CONTROLS
Form 201.28-NM1.EN.PED/CE (0211)
9
Charging Refrigerant into a System
To charge the system with refrigerant, follow the
procedure below:
1. With all system valves open and the Condenser
Drain and Economizer Valves open to 100% by
manually opening them in the Service Mode, charge
refrigerant vapor into the high side of the system at
the charging port on the liquid line. Continue charg-
ing vapor until the pressure is above the freeze point
of the chilled liquid. Once above the freeze point,
liquid can be charged according to the recommend-
ed nameplate charge.
2. Reconnect the water piping to the water boxes.
3. Close the evaporator drain valves and fi ll the evapo-
rator with water from the cooling loop.
4. Fill the water loop and check for leaks.
5. Close (0%) the Condenser Drain and Economizer
Valve in the Service Mode. Recycle the chiller pow-
er.
6. Once the system is operating, the charge will distrib-
ute itself throughout the system. Trim the charge as
needed to a level of about midway on the evaporator
sight glass while running full speed for 15 minutes.
MICROCHANNEL COIL CLEANING
The coil cleaning procedure for microchannel coils is
significantly different than tube and fin type coils. As
such, care must be taken to understand the differences
to avoid damage to the microchannel coil. These
differences require a number of DO NOT’s that must be
observed:
• DO NOT use coil cleaners or any chemical on a
microchannel coil. This can cause severe damage
to the coils.
• DO NOT use a pressure washer to clean the coils.
While it is possible to clean a coil with a pressure
washer, it’s also possible to destroy it.
• DO NOT contact the coil with a hard surface such
as a hose nozzle or metal vacuum nozzle or any
other tool.
Microchannel coils tend to accumulate more dirt on the
surface, but less dirt inside the coils, which makes them
easier to clean. Follow the three steps below for cleaning
the coils:
1. Remove surface debris such as dirt, leaves, insects,
fi bers, etc. with a vacuum cleaner having a soft at-
tachment rather than a metal tube. Compressed air
blown from the inside out can also be used. When
brushing debris off the face of the coil a soft bristle
(not wire) brush can be used. Do not scrape the
coil with the vacuum nozzle, air nozzle, or any other
tool.
2. Rinse the coil with tap water. Do not use coil clean-
ers. Rinse the coil from the inside out, running
water through every passage in the heat exchanger
surface until it is clean. Microchannel coils are
stronger than conventional tube and fi n coils, but
handle them with care, since you can cause a leak
due to impact. Use a gentle spray from a spray noz-
zle with a plastic end or put your fi nger on the end
of the spray nozzle to reduce impact and provide a
gentle spray.
3. Because of the fi n geometry, microchannel coils re-
tain water more than tube and fi n style. It is gener-
ally recommended to blow or vacuum out the rinse
water from the coils to speed drying and prevent
water pooling.
Scheduled Maintenance
The maintenance operations detailed in the following
table should be carried out on a regular basis by a suitably
qualified Service Engineer. It should be noted that the
interval necessary between each ‘minor’ and ‘major’
service can vary depending on, for instance, application,
site conditions and expected operating schedule.
Normally a ‘minor’ service should be carried out every
three to six months and a ‘major’ service once a year. It is
recommended that your local Johnson Controls Service
Center is contacted for recommendations for individual
sites.