Functional problems (page 3 of 3)

In the third case replace the one-level pressure switch installed on the hose connecting the evaporator to the accumulator-dehydrator. In the first case disconnect the power supply cables from the electric fan of the evaporator and check the pressure at which the compressor cuts off. If the expansion valve cuts in at a pressure below 1.38 bars, replace the pressure switch. If it cuts out at 1.38 ÷ 1.93 bars, or if the pressure does not decrease insert a thermometer in the central and side outlets. The same procedure must be followed if the second case arises. If the air temperature leaving the outlets in relation to the environmental temperature is within the limits given in the table the system is working correctly. On the other hand if the temperature of the air leaving the outlets is higher then or equal to the highest value in the table, check the cycles of the compressor. Two conditions may arise:

1. the compressor is continuously engaged;
2. the compressor cuts on and off cyclically or stays off for long periods.
3. In the first case discharge the system and check to see if the expansion valve is missing. If it is, insert a new valve in the second stretch of the hose connecting the condenser to the evaporator and dehydrate and refill the system. If the expansion valve is correctly installed in the hose and in perfectly clean the system is overloaded. Dehydrate and refill the system. If, after the system has been refilled, it still presents problems, replace the accumulator-dehydrator as the dehydrator element will be saturated.
4. In the second case discharge the system and check to see if the expansion valve is blocked. If it is, replace it and then dehydrate and refill the system.

If, on completion of the operation described at point 1 the inlet duct on the evaporator is colder than the outlet duct, check that there are no leaks. If the system is leaking, find the leaks and after remedying the problem dehydrate and refill the system. If there are no leaks add 500 grams of refrigerant and check the engagement and disengagement cycles of the compressor. If the cycles exceed eight per minute, discharge the system and check to see if the expansion valve is blocked. Restore the system, dehydrate and refill. If there are eight cycles or less measure the temperature of the evaporator inlet and outlet ducts. If the temperature if the inlet duct is the same as or higher than that of the outlet duct, add 500 grams of refrigerant. If the temperature of the inlet duct is lower than that of the outlet duct, add 500 grams of refrigerant and again measure the temperature in the two ducts. If the temperature of the inlet duct is lower than that of the outlet duct, discharge the system and check to see if the expansion valve is blocked. Restore the system, dehydrate and refill.