HVAC

• The guideline mentioned in the following section is followed for cleaning, checking and record keeping.
• Sophisticated fault detection and diagnosis (FDD) techniques are employed.
• Energy audit is carried out on annual basis.

• Safe working condition and cleanliness of plant room.

• System connection for leakages preferably with leak detector.
• Condition of all pipe insulation. Care should be taken not to damage or remove insulation during maintenance of equipment.

• Thorough check and maintenance by specialists during annual shutdown.

• Compressor motor terminal connection and insulation.
• Motor current draw correspond to the actual heat load condition.
• Operating condition and calibration of the temperature controller.
• Condition of mounting spring for abnormal noise and vibration.

• Clean compressor motor cooling strainer.
• Replace compressor oil, oil filter and refrigerant filter driers.

Note: After each replacement, the water box should be re-conditioned.

• Vibration analysis test and vales compared to benchmarked frequency

• Fouling factor within operating range.
• Any condenser tube thinned by > 20% of its original thickness should be plugged. When >20% of the all tubes are plugged, the chiller is replaced.

• Pressure test and eddy current test on the condenser tubes.

• Brushing of condenser tubes as per manufacturer’s specification. Any harsh form of cleaning should be avoided.

• Water pressure drop against flow control valve.
• Fouling factor within operating range.
• Calibration of evaporator water gauge.
• Any leakage as indicated by excessive amount of non-condensable.

• Chemical de-scaling with high pressure jet or steam.

• Any loose connection of the refrigerant piping.
• Oil level and refrigerant charge.
• Operation of purge unit.

• Calibration of refrigerant gauge.

• Un-condensable gas and moisture.

• Function of control centre in general and tightness of electrical connections.
• General condition of modulating valve and any loose connections.

• Electronic control compartments.

• Visual inspection for any physical defect, general cleanliness, organic fouling and presence of physical debris – especially before starting the biocide treatment programme.

• Check for abnormal vibration.
• Any brittleness or damage in tower infill.
• Any corrosion and leakage in collection basin.
• Ability of ball valve to adjust collection basin water level. In case of leakage it should be replaced.
• Any crack on fan impeller, fan hubs, and motor shafts.
• Presence of water / sludge in fan gear-reducer oil sample.

• Any corrosion on structural parts (antirust paint should be used).
• Pitching, balancing, and vibration of fan.
• Fan motor insulation.
• Whether the cooling tower housing bolts and nuts are fastened tightly.

• Dirt and algae from louvers, tower-fill and its framework.
• Drain & flush tower fill, collection basin and strainer with water jet.
• Clean fan blades, hubs and fan cylinder.
• Remove any oil spillage from fan or motor gear boxes. Lubricate bearings.

• Thorough cleaning, disinfection and manual de-slugging.

• Replace fan gear box oil.
• Remove any corrosion and scale from condenser water piping, structural steel, and other exposed metals. Next a primer and paint should be applied.

• Use of automatic control system (metering pump & chemical dosage pot).
• At least two types of biocides should be used in ‘shot/slug dose’ method i.e. alternating biocides at suitable intervals.

• Standard plate count test.

• Legionella bacteria count test.

• 25% of all thermostats to be checked thoroughly and calibrated so that all thermostats are serviced on annual basis.
• Any obstruction to the diffusers created by stacked material / partition wall.

• Any damaged insulation of the ducting.
• Operation of dampers – should be quiet.
• Accuracy and correct operation of room thermostats.

• Remove dirt, dust with dry method (brushing, vacuuming), or wet method (with steam or chemical).
• Clean supply and return air ducts, dampers, and actuators except in the mechanical plant room.
• Disinfection of air inlet & outlet, return & exhaust fans, fan housing, plenum, scroll, blades, shafts, baffles, dampers and drive assemblies except in mechanical plant room (BS EN 15780).

• Dislodge debris and dust from the interior duct surfaces with robotics and vacuum collection.