Carrier 69NT40-541-306, Операция и обслуживание

Страница: 107 / 154

7–19 T-354
4. De-scale water tubes with Oakite No. 32 to remove scale.
5. Flush.
6. Neutralize.
7. Flush.
8. 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 Aluminum Cleaner®

164. Mix 170 grams (6 ounces) per 3.785 liters (1 U.S.
gallon) of water. Mix cleaner in one half the volume of water, while stirring, and then add remaining 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.
WARNING
!
Wear rubber gloves and wash the solution from the skin immediately if accidental con tact
occurs. Do not allow the solution to splash onto concrete.
5. Fill the tubes with this solution by filling from the bot tom. See Figure 7.17 .
NOTE
It is important to provide a vent at the top for escaping gas.
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 pail (see Figure 7.18 ) filled with the solution and attached
to the coils by a hose can serve the same purpose by filling and draining. The solution must con tact 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 deter mine
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
Aluminum Cleaner

164 through the tubes to neutralize. Drain this solution.
10. Flush the tubes thoroughly with fresh water.
NOTE
If the condenser cooling water is not being used as drinking water or is not re-circulated in a closed or
tower system, neutralizing is not necessary.
11. Put the unit back in service and operate under normal load. Check the head pressure. If normal, a thorough
de-scaling has been achieved.