Common faults & Symptoms in refrigeration systems :-

(1) Excessive high pressure at compressor discharge.

Air in the system. Air being non-condensable, will collect in the condenser vapour
space and raising the delivery press. By Dalton's Law of partial press the delivery
press will be sum of that due to air and that of refrigerant.

(a)   Overcharge of refrigerant.

(b)Insufficient cooling water to condenser.

(c)   Temp, of cooling water too high.

(d)  Fouling of condenser.

(e)   Condenser cooling water valve inoperative.

(2) Heavy Icing up of crankcase -

(a)Liq. Refrigerant in suction line.

(b)  Exp. v/v bulb wrongly placed.

(c)   Exp. v/v gives too small superheat.

(d)  Compr. Capacity too high during starting i.e. it sucks liquid from the evaporator .

(e)   Oil is foaming in the crankcase.

(3) Excessive vacuum in Compr. Suction -

(a)Refrigerant charge too small.

(b)  Restriction of refrigerant supply, expansion valve clogged.

(c)Expansion valve gives too large superheat.

(d)  Wrongly adjusted capacity regulator.

(e)Filters in suction line clogged.

(f)      Solenoid valve in suction line closed.

(g)   Too much loading of the plant.

(4) Short Cycling-

(a)   Low pressure control difference too small.

(b)  Wrongly adjusted capacity regulator.

(c)Refrigerant too small.

(d)  Expansion valve bulb wrongly placed.

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