Carrier 69NT40-521, 69NT40-511-199 manual Detailed Procedure, Return, Pump Fine mesh Support Screen

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	Gas	Close vent pipe
30 GPM at 35’ head
	vent	valve when pump
Priming
	Globe	is running.
Pumpconnection
	valves
Suction		Condenser
Tank
		Remove water
		regulating valve
		Return
Pump	Fine mesh
support	screen

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.

6-31 T-268-07

SECTION 6