May 2011, Volume 54, Issue 5, pp 1154–1168Vibrational characteristics of piping system in air conditioning outdoor unitArticleFirst Online: 30 March 2011Received: 08 January 2011Accepted: 21 February 2011DOI: 10.1007/s11431-011-4360-xCite this article as: Loh, S.K., Faris, W.F., Hamdi, M. et al. Sci. China Technol. Sci. (2011) 54: 1154. doi:10.1007/s11431-011-4360-xAbstractThe modal analysis of piping system in air conditioner (AC) outdoor unit is essential to investigate the vibration properties of the system. In view of the growing significance of numerical finite element (FE) model for vibration behaviour prediction, the AC piping elastic end support characterization has been explored. The axial and radial stiffness variables (ka, kr1, kr2) of the compressor-piping mounting are obtained and represented by dynamic stiffness of compressor grommet. They are obtained from dynamic load deflection test based on compressor operating condition such as excitation frequency and amplitude.

The unknown stiffness variables of the other tube end (chassis-piping mounting) are determined by parameter fine tuning. An experimental modal analysis using impact hammer test has also been employed to determine the vibration properties such as natural frequencies, mode shapes and damping ratio of the piping structures. The modal parameters acquisition using SCADAS mobile acquisition system and LMS Impact Testing software is compared with the corresponding simulated modal properties using Abaqus. Most of the simulated natural frequencies achieve good correlation with the measured frequencies and it is reasonably a good prediction model to predict vibration behaviour of AC piping structures.Written The repair technicians usually want to sell you a new system if it’s out of warranty. If the pipes between the condenser/compressor unit (outside) and evaporator units (inside) are concealed, they will be costly to replace. It’s actually unusual for them to fail.There are usually 3 pipes for each room unit:Refigerant from compressor to evaporatorRefrigerant return back from evaporator to compressorCondensate (water) drainThe refrigerant pipes for inverter type systems are different from non inverter types.

If you replace a non-inverter a/c type with the more efficient inverter a/c type you have to change the pipes. Otherwise they never seem to change the pipes.The most common problem people experience is blocked condensate drains. This happens when algae grows in the drain pipes and eventually blocks them. Unblocking the drain is a bit tricky because you usually need to disconnect it from the drain coil and blow or suck it clear. A wet and dry vacuum cleaner does this well. ac unit line frozenTo prevent blockage you can periodically dose the drain with household bleach once a month.to keep your a/c working properly I recommend the following simple steps:Clean the filters at least once a month.ac unit for 5000 square feetSet the thermostat temperature at no more than 24 or 25 C. fan coil unit user manual

If you set it colder it doesn't really help - you’ll just risk icing on the evaporator coils whereupon it stops cooling your room as the gaps between the coils get blocked. Set the fan to AUTO.Dose the drains with a cup of bleach once a month.Get a technician to clean the indoor units once every 3 months, and the outside compressor condenser coils at least once a year. They will check refrigerant levels and top up if necessary.Consider using a fan in addition to the a/c. You'll feel cooler at a nay given temperature and use less electricity.Keep the windows and doors closed. Keep the heat out And the cold air in.Servicing is competitively priced. If you skimp on servicing your system will use more power and not work as well.Written They can be fixed but the cost of fixing is not worth going for. I think probably this is the reason the engineer might have suggested you to change the air conditioning. Try the following and see if any of it works:Call an engineer and ask him that you want to shift the location of the Aircon and see if he says Yes/No after knowing about the pipe leakage problem.

Call 2-3 engineers from different companies as I have found that experience of the engineer matter a lot. In my case, I called 3 engineers and all told me a different solution to solve the problem. I figured out that some of them were just guessing. Try to suggest your engineer to use some gas adhesive that seals the pipe and does not allow any leakage. Most of the times, I have seen when you give suggestion to the engineers, they get new ideas to solve the problem. Do not try to solve this by DIY. You will end up in more trouble.Written A photograph would be have been more helpful.I assume that it is not rubber pipe, but a copper pipe with rubber insulation on it. Mostly the instances of the condensation would happen when there are damages in the insulation. I would suggest to repair the insulation damages or change the entire insulation instead of changing the air conditioner.Written I am not an air conditioning specialist. So I read the answers earlier given by others. You may try their adviceBest Luck!

ABSOLUTE ZERO - Complete absence of heat; believed to be -459.67°(-273.15°C). AIR CONDITIONING - Absolute control of temperature and humidity; air conditioning in true sense used only in some laboratories and manufacturing plants where temperature and humidity control are very critical. Ordinary usage in homes, buildings, and vehicles means control of temperature and removal of moisture by condensation; more correct designation is refrigeration. AMBIENT TEMPERATURE - Temperature of surrounding air. In air conditioning, it refers to outside air temperature ATMOSPHERIC PRESSURE - Weight of air and liquid at various altitudes. BOILING POINT - Temperature at which a liquid changes to a vapor. BTU - Abbreviation for British Thermal Unit. Amount of heat required to raise temperature of one pound of water 1°F. All substances are rated in relation to water as standard of measurement. CELSIUS - Thermometer scale based on O°C as freezing point of water and 100°C as the boiling point.

CHARGE - Specific amount of refrigerant by weight or volume. COMPRESSION - Reduction in volume and increase of pressure of a gas or vapor. COMPRESSOR - Component used to change Iow pressure refrigerant to high pressure refrigerant. COMPRESSOR CLUTCH - An electromagnetic coupling that engages or disengages the belt-driven compressor pulley to the compressor shaft. COMPRESSOR DISPLACEMENT - Flgure obtalned by multlplylng dlsplacement of compresor cylinder or cylinders by a given rpm, usually average engine speed. COMPRESSOR SHAFT SEAL - A seal surrounding the compressor shaft that permits the shaft to turn without loss of refrigerant or oil CONDENSATION - Process of changing a gas to a liquid. CONDENSER - Radiator-type component where refrigerator gives off heat by being changed from a gas to a liquid. CONDENSING PRESSURE - Head pressure read from gauge at high side service valve; pressure from discharge side of compressor into condenser. CONDENSING TEMPERATURE - Temperature at which compressed gas in condenser changes from gas to a liquid.

Affected directly by quantity and temperature of ram air passing through condenser. CONDUCTION OF HEAT - Ability of substance to conduct heat (metal and glass conduct heat more readily than insulating material such as spun glass). DENSITY - Weight or mass of a gas liquid or solid. DESICCANT - A drying agent used inside air conditioning systems to absorb and hold moisture. Silica-Gel and Molecular-Sieve are most widely used. DISCHARGE LINE - Line connecting compress outlet to the condenser inlet. DRIER - A device containing a desiccant placed in series, usually in the liquid line, to absorb and hold excess moisture. EVACUATE - To create a vacuum to remove air and moisture in the system. EVAPORATION - Process of changing a liquid to a gas. EVAPORATOR - Component where liquid refrigerant is changed to a gas as it absorbs heat from inside air. EXPANSION - Reduced pressure on liquid refrigerant lowers boiling point and refrigerant changes to a gas and absorbs heat.

EXPANSION VALVE - Device which restricts flow of high pressure refrigerant thus lowering refrigerant pressure. FAHRENHEIT - Thermometer scale based on 32°F as freezing point of water and 212°F as the boiling point of water. FILTER - A device used with the drier or as a separate unit to remove foreign substances from the refrigerant; installed in series in liquid line on high side of system. FLOODED EVAPORATOR COIL - Too much liquid refrigerant in evaporator coil resulting in poor cooling. GAS - A vapor having no particles or droplets of liquid. GAUGE SET - A set of gauges attached to the compressor service valves for testing or measuring pressure or vacuum. HEAD PRESSURE - Pressure of refrigerant from discharge reed valve through lines and condenser to expansion valve orifice. Hg. - Chemical symbol for mercury. mercury is a measure of pressure or vacuum. HIGH SIDE - Same as head pressure; side of system which includes vapor into condenser and liquid to expansion valve.

(Also see Low Side.) HOT GAS BYPASS LINE - Line connecting compressor outlet to evaporator inlet. HYDROLIZING ACTION - Corrosive action within the air conditioning system induced by a weak solution of hydrochloric acid formed by excessive moisture in the system reacting chemically with the Refrigerant-12. JOULE - In air conditioning it is the metric unit of energy or heat (1J = 1055 Btu). kPa - Symbol for kilopascal which is the metric measure of pressure (1 psi = 6.895 kPa). LATENT HEAT - Amount of heat energy required to change a substance from one state of matter to another without changing its temperature. LATENT HEAT OF CONDENSATION - Quantity of heat energy given off while changing a substance from a vapor to a liquid. LATENT HEAT OF FREEZING - Heat given off as a liquid and changed to a solid. LATENT HEAT OF LIQUIDATION - Heat that must be added to change a solid to a liquid. LATENT HEAT OF VAPORIZATION - Quantity of heat energy required to change a liquid into a vapor without raising temperature of vapor above that of original liquid.

LIQUID LINE - Pipe or hose connecting condenser to expansion valve. LOW SIDE - That portion of system from orifice in expansion valve through evaporator line or lines through compressor service valve to compressor reed valve. Also called suction side. MODULATOR VALVE - Device which limits and maintains minimum pressure in the evaporator. PRESSURE - Force upon a body, as force upon a liquid, increases the liquid's boiling point. PRESSURE DROP - Difference in pressure between any two points caused by friction, restriction, etc. PSI - Abbreviation for pounds per square inch above atmospheric pressure. "G" added designates gauge pressure. RADIATION - Heat flow through space, traveling and acting much like light rays. RAM AIR - Air that is forced around the condenser coils as the vehicle travels in a forward direction. RECOVERY EQUIPMENT - Usually a mechanical system that consists of an evaporator, oil separator, compressor, and a condenser which draws refrigerant

out of a refrigeration system and stores it in a container. REFRIGERANT - Liquid used in refrigeration system producing cold by removing heat. SCHRADER VALVE - Spring-loaded valve similar to the tire valve, located inside the gauge hose fitting on service valves and certain controls. Will hold refrigerant in the system but can be opened by installing a special adapter with the gauge hose. SENSIBLE HEAT - Heat which causes a change in temperature of a substance but not a change in state. SIGHT GLASS - Window in receiver-drier or in liquid line to observe refrigerant flow. SPECIFIC HEAT - Quantity of heat required to change the temperature of some amount of a substance. STANDARD TON - Amount of heat released while changing one ton of 33°F (1°C) water to 32°F (O°C) ice in a period of 24 hours. 288,000 Btu (304 MJ) per 24 hours or 12,000 Btu (12.7 MJ) per hour. STARVED EVAPORATOR COIL - Not enough refrigerant supplied to the coil, resulting in poor operation and too-low heat exchange.

SUBSTANCE - Any form of matter that can be weighed or measured; may be solid, liquid, or gas. SUCTION LINE - Line connecting evaporator outlet to compressor inlet. SUCTION SIDE - Low side pressure (from expansion valve orifice to intake reed valve in compressor) . SUCTION THROTTLING - Control used to regulate flow of refrigerant from the evaporator to condenser. SUPERHEAT - Added heat intensity to a gas after complete evaporation of a liquid; controlled by increasing pressure in air conditioning systems. TAIL PIPE - Outlet pipe from evaporator coil. TOTAL HEAT LOAD - Human heat load plus heat entering through floor, glass, roof, and sides of vehicle. TORQUE - Rotating power required to properly tighten a bolt or nut expressed in pounds-foot or pounds-inch (newton-meters). VACUUM - Referred to as less than atmospheric pressure and expressed as inches of mercury in Hg or kilopascals kPa. VISCOSITY - The measure of resistance of a fluid to flow.