Carrier 69NT40-541-001 Operation And Service page 107

If the water-cooled condenser is dirty, it may be cleaned and de-scaled by the following procedure:
a. Turn unit off and disconnect main power.
b. Disconnect water pressure switch tubing by loosening the two flare nuts. Install one-quarter inch flare
cap on water-cooled condenser inlet tube (replaces tubing flare nut). De-scale tubing if necessary.
What You Will Need:
1. Oakite composition No. 22, available as a powder in 68 kg (150 lb) and 136 kg (300 lb) containers.
2. Oakite composition No. 32, available as a liquid in cases, each containing 3.785 liters (4 U.S. gallon)
bottles and also in carboys of 52.6 kg (116 lbs) net.
3. Fresh clean water.
4. Acid proof pump and containers or bottles with rubber hose.
When Oakite compound No. 32 is being used for the first time, the local Oakite Technical Service rep-
resentative should be called in for their suggestions in planning the procedure. They will advise the
reader on how to do the work with a minimum dismantling of equipment: how to estimate the time and
amount of compound required; how to prepare the solution; how to control and conclude the de-scal-
ing operation by rinsing and neutralizing equipment before putting it back into service. Their knowl-
edge of metals, types of scale, water conditions and de-scaling techniques will be highly useful.
Summary of Procedure:
a. Drain water from condenser tubing circuit. Clean water tubes with Oakite No. 22 to remove mud and slime.
b. Flush.
c. De-scale water tubes with Oakite No. 32 to remove scale.
d. Flush.
e. Neutralize.
f. Flush.
g. 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 accom-
plished 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.
Oakite No. 32 is an acid. Be sure that the acid is slowly added to the water. DO NOT PUT
WATER INTO 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.
Fill the tubes with this solution by filling from the bottom. See
the top for escaping gas.
NOTE
WARNING
!
WARNING
!
Figure 7.17. Important: be sure to provide a vent at
7–19 T-316