Good Servicing Practices

1. Good Servicing Practices

2. WHY ?

3. * A very large proportion of refrigerant supplied to the refrigeration and air-conditioning industry is used to service and maintain existing systems. * Thus it is used to replace refrigerant that has already escaped to atmosphere. * Therefore, there is a great potential for reducing emissions by improving service and maintenance procedures and practices. UNEP

4. A B WHO IS BETTER?

5. Areas of Focus • Brazing • Cleaning and Flushing • Leak Testing • Evacuation • Measurement / holding of vacuum • Charging of Refrigerant • Cross contamination • Installation

6. Brazing Filler Rod Base Metal • Melts at temperature lower than that of base metals • Rod should melt by contact with heated base metal • Melted Rod Material flows into clearance between walls of the two tubes through capillary action Torch Brazing Filler Rod Essentials of Brazing

7. Essentials of Brazing (contd.) Boundary locking layers (dotted) show metallurgical bond Filler material Tube hollow Outer tube end (swaged) Inner tube Melted Filler Rod material wets base metal and penetrates surface & forms metallurgical bond.

8. Right brazing alloys; Right Flux • Right Joint preparation • Surface preparation • Joint clearances Right technique Right temperature Good Brazed Joints: Prerequisites

9. Desired temperature range for Phos Cu Alloys 8150C Average temperature for Phos Cu Alloys 7050C 6000C Right temperature for Cu Ag alloys (Ag >35%) 5900C Temperature for Brazing

10. Suitability of Brazing Equipment • Oxy Acetylene: Best suited • Oxygen-LPG: Better suited than Air-LPG • Air-LPG: May be inadequate, but O.K. for Cu tubes up to 3/8” with Powerjet (or Cyclone) Torches

11. USE. Dry Nitrogen Hexane/MDC/ Trichloroethylene (for chemical cleaning) * Always read MSDS before use DO NOT USE CTC (Being phased out) Air (Contains moisture, lubricant & other gases, detrimental to the system) Oxygen – not O.K. for compressor oil Petrol (has a lot of impurities which can destroy the compressor) Cleaning and Flushing

12. USE. Dry Nitrogen (after the system has been reassembled) Should have a dew point of at least -400C Commercial nitrogen with a drier (to reduce moisture content) DO NOT USE Compressed air (Contains moisture, lubricant & other gases, detrimental to the system) Refrigerant Leak Testing

13. DO NOT USE Refrigeration System’s compressor Other Hermetic / Semi Hermetic / Open Refrigeration compressors May lead to compressor failure as: moisture gets deposited in compressor’s discharge chamber there can be loss of lubricant Equipment for Evacuation • Creates inadequate vacuum for moisture to boil and vacate the system

14. Why Vacuum Pump is needed

15. Equipment for Evacuation(Cont) • Use specially designed vacuum pumps, capable of developing blank off pressure of 20 - 50 microns Hg • Micron gauge capable of reading pressures in 5 - 5000 Microns range • Most preferred: • Two stage, Rotary, multi-vane pump

16. Measuring Vacuum Accurately • Use Pirani / Thermocouple vacuum gauge having a range from 5-5000/10000 microns • Evacuate to about 500 microns or lower • Isolate the vacuum pump & observe the rise in the vacuum for 5-10 minutes • Repeat (a) & (b) till the vacuum in (b) stabilizes at around 1500 microns or lower. The lower the stabilized vacuum the better.

17. Charging • Charge the same weight of refrigerant in the system, as recommended by the appliance manufacturer instead of charging by feel (To ensure good cooling performance and low energy consumption) • Charging apparatus must provide for accurate weighing scales or calibrated charging cylinders (HFC-134a & HCs particularly are even more sensitive to charge quantity than CFC-12)

18. Contamination &Cross Contamination Contamination by : • Moisture • Non-condensables • Chemical residues • Dirt, dust metal particles • Organic contaminants Cross-Contamination through: • Import of contaminants from other systems or servicing equipment Contaminants: • Other refrigerants, other lub. Oils, chemical residues from other systems

19. Cross-Contamination due to Refrigerant Mixing • Even at 10-20% of CFC-12 in HFC-134a & vice-versa, the azeotrope formed will have properties quite different from either • This will seriously affect appliance performance • Similar problems will arise with mixtures of CFC-12 & HCFC-22 or HCFC-22 & HFC-134a • As full data on HCs / CFC-12 or HCs / HFC-134a mixing is not available, it is better to avoid their mixing. CAUTION: Ensure that refrigerants do not mix.AVOID.

20. Cross-Contamination due to Refrigerant Mixing Do's & Don'ts - 2012 20

21. Likely Sites for Refrigerant Cross-Contamination • Charging stills of E&C units, used for multiple refrigerants • Recovery & R&R machines used for multiple refrigerants • Recovery cylinders • Hoses & Manifolds • Old systems retrofitted with non-CFC refrigerants

22. How to avoid Refrigerant Cross-Contamination (Cont) • Ensure that all traces of the previous refrigerants is removed from the charging still / recovery machine & the unit is evacuated to a deep vacuum (1000 microns) before switching to a new refrigerant • If possible use separate E&C & Recovery machines for each type of refrigerants • Use separate recovery cylinders for each refrigerant

23. Gap is less than 2”, after some time wall will be hot Wrong Installation

24. Wrong v/s. right Installation

25. Wrong v/s. right Installation X √ U Trap is must for drains

26. Result wrong installations Flow:Flow of air will go from exhaust fan to wall side. It will heat the wall, the glass door and rest. Circulation of air:Hot air will be circulated time & again increasing the temperature of air and the same air will enter to condenser, decreasing condensation and increasing head pressure which leads to high current i.e. higher energy consumption.

27. X Trying to vacuum with long pipe and small reciprocating compressor. √ Use double stage vacuum pump for evacuation. During Repair

28. Results Wrong Repair Non condensable left out in the system leads: • High refrigerant charge • High head pressure • High current

29. Refrigeration and air-conditioning systems are large users of electrical energy and represent huge capital investments. To maintain these systems, we should ensure (i) low leaks of refrigerants and (ii) lowest possible energy consumption, resulting to : • lowest possible impact of the environment from Ozone Depleting Substances and on Global Warming from (a) direct emissions of refrigerants as well as from (b) indirect effects from Carbon Dioxide (CO2) emissions caused by energy consumption.

30. Energy Efficiency _ “Negawatt”-A unit of energy saved. • The cleanest, most reliable and cheapest energy is the energy we don’t use. • Energy efficiency is a “triple-win” solution to the “energy trilemma” of simultaneously • (a) tackling climate change (and other environmental challenges), • (b) ensuring security of supply and • (c) providing affordable access to energy.

31. No or less Servicing BEFORE SERVICE Initial Line Current = 2.4 Amp DUST

32. No or less Servicing AFTER SERVICE Final Line Current =1.7 Amp

33. GOOD MAINTENANCE LEADS NET EXCHEQUERSAVING of Rs. 1.29Lac /year P = √3 x V x I x cos ф P = 1.732 x 230 x 2.4 x 0.9 = 861Watts P = 1.732 x 230 x 1.7 x 0.9 = 610 Watts Saving = 251 Watt/hr. Saving = 251 x 24 = 6,024 Watt Per day saving is 6 KWh 1 Kwh = 1 Kilo Watt Hour 1 Kwh = 1 Electrical Unit 1 Kwh = 1000 W consumed in 1 Hour Saving: Rs.1080 per month for 10 cooling units + less GWP @6/- per unit x 6 x 30 days = Rs. 2070/-month Rs. 1080/month x 12 x 10 units = Rs. 1,29,600/-

34. Result no servicing or improper servicing You have seen the calculation.

35. Good Servicing Practice includes Refrigerant Recovery and Recycling

36. Let us do the best service practices *** Let us SAVE our MOTHER EARTH

37. THANK YOU