Trane SCXG-SVX01B-EN manual Coil Freezeup

maintenance

Maintenance procedures

Inspecting and Cleaning Coils

Coils become externally fouled as a result of normal operation. Coil surface dirt reduces heat transfer ability and can cause comfort problems, increased airflow resistance and thus increased operating energy costs.

Inspect coils at least every six months or more frequently as dictated by operating experience. Cleaning frequently is dependent upon system operating hours, filter maintenance, efficiency, and dirt load. Following is the suggested method for cleaning steam and hot water coils.

Steam and Hot Water Coils

1.Disconnect all electrical power to the unit.

2.Wear the appropriate personal protective equipment (PPE).

3.Access both sides of the coil section.

4.Use a soft brush to remove loose debris from both sides of the coil.

5.Use a steam cleaning machine, starting from the top of the coil and working downward. Clean the leaving air side of the coil first, then the entering air side. Use a block-off to prevent steam from blowing through the coil and into a dry section of the unit.

6.Repeat step 5 as necessary. Confirm that the drain line is open following completion of the cleaning process.

7.Allow the unit to dry thoroughly before putting the system back into service.

8.Straighten any coil fins that may be damaged with a fin rake.

9.Replace all panels and parts and restore electrical power to the unit.

10.Ensure that contaminated material does not contact other areas of the equipment or building. Properly dispose of all contaminated materials and cleaning solutions.

Refrigerant Coils

1.Disconnect all electrical power to the unit.

2.Wear the appropriate personal protective equipment (PPE).

3.Access to the coil section of the unit (both sides).

4.Use a soft brush to remove loose debris from both sides of the coil.

5.Mix a high quality coil cleaning detergent with water according to the manufacturer’s instructions. If the detergent is strongly alkaline after mixing (pH 8.5 or higher), it must contain an inhibitor. Carefully follow the cleaning solution manufacturer’s instructions regarding product use.

6.Place the mixed solution in a garden pump-up sprayer or high pressure sprayer. If using a high pressure sprayer note the following:

•Maintain a minimum nozzle spray angle of 15°

•Spray perpendicular to the coil face

•Protect other areas of the equipment and internal controls from contact with moisture or the cleaning solution

•Keep the nozzle at least six inches from the coil

•Do not exceed 600 psig

Draining theWaterside Economizer Coil

NOTICE

Coil Freezeup!

Properly drain and vent coils when not in use.Trane recommends glycol protection in all possible freezing applications. Use a glycol approved for use with commercial cooling and heating systems and copper tube coils. Failure to do so may result in equipment damage.

Drain plugs are in the piping below each coil’s supply and return header. Use these plugs to drain the coil and piping.When draining the coil, open the vents at the top of the supply and return headers. Also, a drain plug is at the bottom of the inlet condenser manifold and in the outlet pipe near the unit’s left side. Remove these plugs to drain the condensers. Be sure to open the vent plugs at the top of the condenser inlet and outlet manifold. See Figure O-M-9.

When refilling the condenser/waterside economizer coil system with water, provide adequate water treatment to prevent the formation of scale or corro- sion.

Cleaning the Condenser

NOTICE

ProperWaterTreatment!

The use of untreated or improperly treated water in a CenTraVac may result in scaling, erosion, corrosion, algae or slime. It is recommended that the services of a qualified water treatment specialist be engaged to determine what water treatment, if any, is required.Trane assumes no responsibility for equipment failures which result from untreated or improperly treated water, or saline or brackish water.

Condensing water contains minerals that collect on the condenser tube walls. Cooling towers also collect dust and foreign materials that deposit in the condenser tube.The formation of scale or sludge in the condenser is indicated by a decreased water flow, low temperature difference between inlet and outlet water, and abnormally high condensing tem- peratures.To maintain maximum condenser efficiency, the condenser must remain free of built-up scale and sludge. Clean the condenser either mechanically or chemically.

Mechanical Cleaning of Condenser and Economizer Coils

1.Turn off the condenser supply water. Remove drain plugs discussed in the “Draining the Coil” section on page 91.

2.Remove the condenser head to expose the condenser tubes.

3.Rotate a round brush through the tubes to loosen contaminant.

4.Flush tubes with water to push the sludge out through the drain opening in the bottom of the supply header and the return pipe.

5.To clean the economizer tubes, remove the cast iron header plates at both sides of the coil between the inlet and outlet headers (four-row coils only; two-row coils do not have cover plates at right end). Rotate round brush through tubes from left end to loosen contaminants. Flush tubes with water.

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