Aircon repair

[AndyC]

Due to lack of cold air I had the system on my 96 C200 checked. The clutch on the compressor was not working (belt not spinning), which I had noticed and I needed a re gas. When it was repaired I was charged for a condenser unit and a dryer unit and gas was recharged. Everything that should be spinning now is and I have cold air again. Any ideas as to whether the faults tie up with the remedy? :?:

 

[BillyBoy]

It sounds reasonable if you were low on refrigerant. Most AC systems have a cut out switch to stop the compressor engaging if the system looses too much gas and thus saving on replacing the (very expensive) compressor. Replacing the dryer is a standard procedure on a re-gas for many systems. Don't know about the condensor.

I had a Scorpio before I bought the Merc, and foind the Scorpio web site full of useful generic information on things like this as well as scorpio specific info. Have a look at http://www.fordscorpio.co.uk/acindex.htm for some nice explainations on AC and CC.

HTH,

Bill

 

[simon paynter]

your condenser , the unit in front of the engine radiator probably had a hole in it , often lumps of salt stick in the fins and csuse corrosion and then a leak or sometimes a stone or other foriegn object, if the gas leaks out completely then moisture will be allowed into the system, this is harmful to the system as it causes internal corrosion and damage to system hence the filter drier change
After re assembly an `air con system should be vacuumed down to close to 30 inches of mercury ( a measurement on the air con service guages,) it should then be left for some time to see if it has returned towards atsmospheric pressure if it holds its vacuum then all well and good and the system can be regassed. Modern gases like R134a are normally charged into the system according to specification ie the system is designed to hold 1.1 Kg of gas so that is what is weighed in R134a systems run at much higher pressures than the old R12 systems due to lower effeciency of the gas
Air con systems have a certain amount of oil in them which is mainly contained in the compressor , but also travels all round the system

R12 systems on older cars can be recharged or toppd up with a drop in gas designed to mix in with R12 no change of components or oil is necessary

hope this answers your questions

 

[simon paynter]

your condenser , the unit in front of the engine radiator probably had a hole in it , often lumps of salt stick in the fins and csuse corrosion and then a leak or sometimes a stone or other foriegn object, if the gas leaks out completely then moisture will be allowed into the system, this is harmful to the system as it causes internal corrosion and damage to system hence the filter drier change
After re assembly an `air con system should be vacuumed down to close to 30 inches of mercury ( a measurement on the air con service guages,) it should then be left for some time to see if it has returned towards atsmospheric pressure if it holds its vacuum then all well and good and the system can be regassed. Modern gases like R134a are normally charged into the system according to specification ie the system is designed to hold 1.1 Kg of gas so that is what is weighed in R134a systems run at much higher pressures than the old R12 systems due to lower effeciency of the gas
Air con systems have a certain amount of oil in them which is mainly contained in the compressor , but also travels all round the system

R12 systems on older cars can be recharged or toppd up with a drop in gas designed to mix in with R12 no change of components or oil is necessary

hope this answers your questions

 

[simon paynter]

your condenser , the unit in front of the engine radiator probably had a hole in it , often lumps of salt stick in the fins and csuse corrosion and then a leak or sometimes a stone or other foriegn object, if the gas leaks out completely then moisture will be allowed into the system, this is harmful to the system as it causes internal corrosion and damage to system hence the filter drier change
After re assembly an `air con system should be vacuumed down to close to 30 inches of mercury ( a measurement on the air con service guages,) it should then be left for some time to see if it has returned towards atsmospheric pressure if it holds its vacuum then all well and good and the system can be regassed. Modern gases like R134a are normally charged into the system according to specification ie the system is designed to hold 1.1 Kg of gas so that is what is weighed in R134a systems run at much higher pressures than the old R12 systems due to lower effeciency of the gas
Air con systems have a certain amount of oil in them which is mainly contained in the compressor , but also travels all round the system

R12 systems on older cars can be recharged or toppd up with a drop in gas designed to mix in with R12 no change of components or oil is necessary

hope this answers your questions

 

[Mr Fridge]

To dehydrate a system or to clear moisture you need to use a good quality 2 stage vacuum pump and a torr gauge and evacuate / dehydrate down to 1 mbar ( any moisture will boil off above atmospheric pressure ) , if it pulls to 1 mbar you have no more leaks, if it pulls to 4mbar and a pressure rise test results in a small rise of the gauge needle probably a small leak but enough to last the season, if the pressure rise does not pull down to 4 and rises immediately, you have a leak, meantime your service engineers gauge will still show a 25 / 30 inch vacuum, a torr gauge is an excellent tool and a good indication of a gas tight system or not.

 

[AndyC]

Thanks for all the info guys. Much appreciated.