Trane CAUC-C20, Installation Operation & Maintenance

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Service and Maintenance (Continued)
System operation
[ ] Close the main power disconnect switch for the Con-
densing Unit and all system support equipment. Turn all
system control circuit switches to the “On” position.
HAZ A R D O U S V O L TA G E
R O T A T I N G P A R T S !
UNIT STARTS AUTOMATICALLY
Make sure all personnel are standing clear of the unit
before proceeding. The system components will start
when the power is applied.
[ ] With the unit running, check and record the:
ambient temperature;
compressor oil level (each circuit);
compressor suction and discharge pressures (each
circuit);
superheat and Subcooling (each circuit);
Record this data on an “operator’s maintenance log”
simular to the one illustrated in the “Final Setup” section
of this manual. If the operating pressures indicate a re-
frigerant shortage, measure the system Superheat and
system Subcooling. For guidelines, refer to the “system
Start-Up” section.
Note: Do Not release refrigerant to the
atmosphere! If adding or removing refrigerant is
required, the service technician must comply with
all federal, state and local laws. Refer to general
service bulletin MSCU-SB-1 (latest edition).
Coil Cleaning
Regular coil maintenance, including annual cleaning, en-
hances the unit’s operating efficiency by minimizing:
compressor head pressure and amperage draw;
evaporator water carryover;
fan brake horsepower, due to increase static pressure
losses;
airflow reduction.
At least once each year, or more often if the unit is located
in a “dirty” environment, clean the evaporator and con-
denser coils using the instructions outlined below. Be sure
to follow these instructions as closely as possible to avoid
damaging the coils.
To clean refrigerant coils, use a soft brush and a sprayer
(either a garden pump-up type or a high-pressure sprayer).
A high-quality detergent is also required; suggested brands
include “SPREX A.C.”, “OAKITE 161”, “OAKITE 166” and
“COILOX”. If the detergent selected is strongly alkaline (ph
value exceeds 8.5), add an inhibitor.
1. Remove enough panels from the unit to gain access to
the coil.
2. Protect all electrical devices such as motors and control-
lers from any overspray.
3. Straighten any bent coil fins with a fin comb.
4. Mix the detergent with water according to the
manufacturer’s instructions. If desired, heat the solution
to 150
o F maximum to improve its cleansing capability.
CONTAINS REFRIGERANT!
SYSTEM CONTAINS OIL AND REFRIGERANT
Do not heat the detergent-and-water solution above
150 o F. Hot liquids sprayed on the exterior of the coil
will raise the coil’s internal pressure and may cause
it to burst.
Failure to follow proper procedures can result in per-
sonal illness or injury or severe equipment damage.
Note: Refrigerant oil is detrimental to some roofing
materials. Care must be taken to protect the roof
from oil leaks or spills.
5. Pour the cleaning solution into the sprayer. If a high-pres-
sure sprayer is used:
a. do not allow sprayer pressure to exceed 600 psi.
b. the minimum nozzle spray angle is 15 degrees.
c. maintain a minimum clearance of 6" between the
sprayer nozzle and the coil.
d. spray the solution perpendicular (at 90 degrees) to
the coil face.
6. Spray the leaving-airflow side of the coil first; then spray
the opposite side of the coil. Allow the cleaning solution
to stand on the coil for five minutes.
7. Rinse both sides of the coil with cool, clean water.
8. Inspect both sides of the coil; if it still appears to be dirty,
repeat Steps 6 and 7.
9. Reinstall all of the components and panels removed in
Step 1 and any protective covers installed in step 2.
10. Restore the unit to it’s operational status and check sys-
tem operation.