Carrier 69NT40-511-199 - Manual (Page 125)

SECT
IO
N
6
6-31 T-268-07
7. Put unit back in service under normal load and
check head (discharge) pressure.
Detailed Procedure:
1. Drain and flush the water circuit of the condenser
coil. If scale on the tube inner surfaces is
accompanied by slime, a thorough cleaning is
necessary before de-scaling process can be
accomplished.
2. To remove slime or mud, use Oakite composition
No. 22. Mixed 170 grams (6 ounces) per 3.785 liters
(1 U.S. gallon) of water. Warm this solution and
circulate through the tubes until all slime and mud
has been removed.
3. After cleaning, flush tubes thoroughly with fresh
clean water.
4. Prepare a 15% by volume solution for de-scaling,
by diluting Oakite compound No. 32 with water.
This is accomplished by slowly adding 0.47 liter (1
U.S. pint) of the acid (Oakite No. 32) to 2.8 liters (3
U.S. quarts) of water.
WARNING
Oakite No. 32 is an acid --be sure that the
acid is slowly added to the water. DO NOT
PUT WATER INTO THE ACID! -- this will
cause spattering and excessive heat.
Wear rubber gloves and wash the solution
from the skin immediately if accidental
contact occurs. Do not allow the solution to
splash onto concrete.
5. Fill the tubes with this solution by filling from the
bottom. See Figure 6-32. Important: be sure to
provide a vent at the top for escaping gas.
Centrifugal pump
30 GPM at 35’ head
Pump
Suction
Pump
support
Tank
Fine mesh
screen
Return
Remove water
regulating valve
Condenser
Globe
valves
Gas
vent
Close vent pipe
valve when pump
is running.
Priming
connection
Figure 6-32. Water-Cooled Condenser Cleaning --
Forced Circulation
6. Allow the Oakite No. 32 solution to soak in the tube
coils for several hours, periodically
pump-circulating it with an acid-proof pump.
An alternate method may be used whereby a bottle (see
Figure 6-33) filled with the solution and attached to the
coils by a hose can serve the same purpose by raising
and lowering of the bottle. The solution must contact the
scale at every point for thorough de-scaling. Air pockets
in the solution should be avoided by regularly opening
the vent to release gas. Keep flames away from the vent
gases.
7. The time required for de-scaling will vary,
depending upon the extent of the deposits. One way
to determine when de-scaling has been completed is
to titrate the solution periodically, using titrating
equipment provided free by the Oakite Technical
Service representative. As scale is being dissolved,
titrate readings will indicate that the Oakite No. 32
solution is losing strength. When the reading
remains constant for a reasonable time, this is an
indication that scale has been dissolved.
8. When de-scaling is complete, drain the solution and
flush thoroughly with water.
9. Following the water flush, circulate a 56.7 gram (2
ounce) per 3.785 liter (1 U.S. gallon) solution of
Oakite No. 22 thru the tubes to neutralize. Drain this
solution.
10. Flush the tubes thoroughly with fresh water.