Service and Maintenance
186
RT-SVX24J-EN
c. Spray the solution perpendicular (at 90 degrees) to
the coil face.
d. For evaporator and reheat coils, maintain a
minimum clearance of 6" between the sprayer
nozzle and the coil. For microchannel condenser
coils, optimum clearance between the sprayer
nozzle and the microchannel coil is 1"-3”.
6. Spray the leaving-airflow side of the coil first; then
spray the opposite side of the coil. For evaporator and
reheat coils, 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; then restore power to the unit.
10. For evaporator and reheat coils, use a fin comb to
straighten any coil fins which were inadvertently bent
during the cleaning process.
Steam or Hot Water Coils
To clean a steam or hot water coil, use a soft brush, a
steam-cleaning machine, and water.
1. Verify that switches 1S1 and 1S70 are turned “OFF”,and
that the main unit disconnect is locked open.
2. Remove enough panels and components from the unit
to gain sufficient access to the coil.
3. Straighten any bent coil fins with a fin comb. (Use the
data in
Table 58, p. 179
to determine the appropriate fin
comb size.)
4. Remove loose dirt and debris from both sides of the
coil with a soft brush.
5. Use the steam-cleaning machine to clean the leaving-
air side of the coil first; start at the top of the coil and
work downward; then clean the entering-air side of the
coil, starting at the top of the coil and working
downward.
6. Check both sides of the coil; if it still appears dirty,
repeat Step 5.
7.
Reinstall all of the components and panels removed in
Step 2; then restore power to the unit.
Evaporative Condenser Coil Cleaning
Sump Water Management
Water Supply
Overall performance of any water- cooled device can be
affected by suspended particulates, mineral
concentration, trash and debris resulting in clogging and
heat transfer loss.The unit is designed to greatly minimize
problems with these impurities, however, float valves and
solenoid valves are used to control the incoming water.
If the incoming water contains contaminants, sand or
other objects, it is best to insert an incoming line strainer
having a mesh of 80 to 100.The inlet line should be flushed
prior to connection to the unit, whether or not there is a
strainer.
There is an air gap between the water inlet float valve and
sump water level to prevent back flow; however, if local
code dictates, a backflow prevention valve may be
required (field-provided and installed by a qualified
technician).
Water Drain
Local Site Discharge: Rooftop or simple storm sewer
discharge is generally acceptable. Do not routinely direct
the sump discharge onto an area that will be adversely
affected. For example, continued sump discharge into a
flower bed where the input water contains CaCO3 (lime)
will eventually decrease the pH of the soil.
Sewer Discharge: The quantities of mineral and debris
flushed are actually very small and do not cause problems
when diluted in normal sewer flow. However, local, state
or federal standards and restrictions must be followed in
any given locality.
Traditional Bleed Method
ASHRAE recommendation for continuous bleed rates:
With good, quality makeup water, the bleed rates (0.8 - 2
GPH/ton) may be as low as one-half the evaporation rate
(1.6 -2 GPH), and the total water consumption would range
from 2.4 GPH/ton for air conditioning to 3 GPH/ton for
refrigeration (Chapter 36.17 of ASHRAE's “Systems and
Equipment Handbook”)
Operation and Care
The sump should be inspected at least every 6 months for
possible build up of scale pieces that has been shed from
the coils. The sump flush frequency or bleed rate should
be increased if large amounts of scale are present.
If the water has a “milky or cloudy” appearance, then
minerals are concentrating in the sump and the number of
flushes should be increased.
If the water remains clear between flushes, then the
number of flushes can be decreased.Through field trials,
the optimum flush frequency can be determined. Please
note that in some areas, water quality can vary during
WARNING
No Step Surface!
Do not walk on the sheet metal drain pan. Walking on
the drain pan could cause the supporting metal to
collapse, resulting in the operator/technician to fall.
Failure to follow this recommendation could result in
death or serious injury.
