Carrier 69NT40-541-306 Operation And Service
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T-354 7–18CAUTION!Take necessary steps (place plywood over coil or use sling on motor) to prevent motor fromfalling into condenser coil.3. Remove motor mounting hardware and replace the motor. It is recommended that new locknuts be usedwhen replacing motor. Connect wiring per wiring diagram.4. Install fan loosely on motor shaft (hub side in). DO NOT USE FORCE. If necessary, tap the hub only, not thehub nuts or bolts. Install venturi. Apply “Loctite H” to fan set screws. Adjust fan within venturi so that theouter edge of the fan projects 3.2 to 6.4mm (3/16” to 1/16”) back from edge of the venturi. Spin fan by handto check clearance.5. Close and secure condenser fan screen guard.6. Apply power to unit and check fan rotation. If fan motor rotates backward, reverse wire numbers 5 and 8.7.12 WATER-COOLED CONDENSER CLEANINGThe water-cooled condenser is of the shell and coil type with water circulating through the cupro-nickel coil. Therefrigerant vapor is admitted to the shell side and is condensed on the outer surface of the coil.Rust, scale, and slime on the water-cooling surfaces inside of the coil interfere with the transfer of heat, reducesystem capacity, cause higher head pressures and increase the load on the system.By checking the leaving water temperature and the actual condensing temperature, it can be determined if the con-denser coil is becoming dirty. A larger than normal difference between leaving condensing water temperature andactual condensing temperature, coupled with a small difference in temperature of entering and leaving condensingwater, is an indication of a dirty condensing coil.To find the approximate condensing temperature, with the unit running in the cooling mode, install a gauge 0 to36.2kg/cm (0 to 500psig) on the compressor discharge service valve.Example: Discharge pressure is 10.3kg/cm 2 (146.4psig). Referring to Table 6-8 (R-134a pressure/ temperaturechart), the 10.3kg/cm 2 (146.4psig) value converts to 43° C (110° F).If the water-cooled condenser is dirty, it may be cleaned and de-scaled by the following procedure:1. Turn unit off and disconnect main power.2. Disconnect water pressure switch tubing by loosening the two flare nuts. Install one-quarter inch flare capon water-cooled condenser inlet tube (replaces tubing flare nut). De-scale tubing if necessary.What You Will Need:• Oakite Aluminum Cleaner® 164, available as a powder in 20kg (44lb) pails and 205kg (450lb) drums.• Oakite composition No. 32, available as a liquid in cases, each containing 3.785 liters (4 U.S. gallon) bottlesand also in carboys of 52.6kg (116lbs) net.• Fresh clean water.• Acid proof pump and containers or bottles with rubber hose.NOTEWhen Oakite compound No. 32 is being used for the first time, the local Oakite Technical Service rep-resentative should be called in for assistance in planning the procedure. They will advise the reader onhow to do the work with a minimum dismantling of equipment, estimate the time and amount of com-pound required, preparation, how to control and conclude the de-scaling operation by rinsing and neu-tralizing equipment before putting it back into service.Summary of Procedure:1. Drain water from condenser tubing circuit.2. Clean water tubes with Aluminum Cleaner® 164 to remove mud and slime. Clean water tubes with OakiteNo. 22 to remove mud and slime.3. Flush. |
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