Leak Detection All Refrigerant: Soap bubble Ultrasonic : 0.05mm hole , 14 m range Pressure : by makers

Leak Detection Halogenated Refrigerant: Halide lamp Electronic pale blue to green to violet Electronic all except R14 – very sensitive –measures resistance of vapour confined to production work affected by carbon monoxide and alcohol

Leak Detection Ammonia Sulphur candle / sulphur dioxide (cans) white cloud of ammonia sulphate Hydrochloric acid white cloud ammonia chloride Litmus paper difficult if leak’s major

Indication of leakage Oil weeping from joints/connections Low level / large bubbles in sight glass Low suction pressure High superheat Continuous running Difficult to maintain temperature Odour – in ammonia plant

Sudden efficiency drop (causes) Refrigeration loss Broken valves Icing up of TX valves Belt slipping

Short Cycling on H.P. (causes) Condenser cooling Fouled condenser Overcharging Air in system Wrong adjustment of switch

Short Cycling on L.P. (causes) Frosted evaporator coils Choked strainer/drier Leaky discharge valves Defective TX valves; wrong orifice Under charge Wrong adjustment of switch

Poor cooling in condenser (causes) Cooling water High H.P. Reading incorrect Pump fault Choked strainer Fouled condenser High S.W.. temperature

Undercharge (symptoms) Large bubbles in sight glass Low discharge pressure Low suction pressure Prolong running Less frosting on suction Performance drop Action : Leak test, rectify and recharge

Overcharge (symptoms) Sight glass full High discharge pressure Cut out on H.P. More frosting on suction Action: pump to condenser and use recovery system to release

Liquid at suction( symptoms) Crankcase frosting Oil loss Noise High H.P.

Moisture (symptoms) Inlet to TX frosting Drier frosting up Low suction pressure Action: renew drier until all moisture removed.

Coil Frosting (effect) Runs longer Short cycling on L.P. Drop in performance Action : defrost

Contaminants Oil Reduces heat transfer Oil separator more at low temperature Oil separator Ammonia not miscible condenser drains

Contaminants Water Ice in low temperature region Corrosion Copper plating ; staining of valve plates, etc Electrical Insulation breakdown Driers / Anti-freeze 15ppm (R12) ; 25ppm(R22) during manufacture Vacuum after repair

Contaminants Air / non-condensable gases Increase pr Noisy compressor Performance drop Bubbles in sight glass Compare pressure with saturated vapour pressure Purge from condenser

Contaminants Copper plating When moisture is present Copper picked up by Freon Deposit on liners, piston , valves etc

Operational Faults Loss of oil from crankcase Suction pressure drop suddenly during start up load reduction Liquid Freon evaporates Foaming – leading to oil carried away

Operational faults Excessive oil Collect in coils - reduce heat transfer Low suction pressure , noisy compressor

Operational Faults To prevent damage due to oil loss Minimise pressure fluctuation Suitable TX valve Use de-foaming agent Pump down if long shut-down Ensure oil returned from system No condensed liquid from evaporator during shut-down

TX valve problem TX valve strainer clogged Remote bulb dislodged check by cooling and warming If oversize: overfeeding at part load If undersize: overloaded at full load