Datatek
Well-Known Member
€20 for a can for mine compared to €80 at a garage.
Graculus
Well-Known Member
The thing with the cans is:-
1. you don't know how much is in the system so you could be under or overcharging - neither are good for the longevity of the compressor or seals.
2. vacuuming the system removes accumulated moisture from the filter-drier, along with other contaminants and any excess oil, obviously that can never happen with the top-up cans.
3. Although there is some natural loss over time, just topping up the system is not the same as a vacuum leak check - and I fully accept that a vacuum check is not the same or as good as a pressure test, but it's better than nothing.
1. you don't know how much is in the system so you could be under or overcharging - neither are good for the longevity of the compressor or seals.
2. vacuuming the system removes accumulated moisture from the filter-drier, along with other contaminants and any excess oil, obviously that can never happen with the top-up cans.
3. Although there is some natural loss over time, just topping up the system is not the same as a vacuum leak check - and I fully accept that a vacuum check is not the same or as good as a pressure test, but it's better than nothing.
ok but he bought 4 cans... so for a one-off, pay the same and get it done properly... (?)
ChrisFix did a YT video on how to do it, I assume it's worth buying the kit if you've got more than 1 car to do...
link to chrisfix youtube video
no
like i said i had i small leak on the compressor
and i didnt have time to do anything
i live in the south fo france in the middle of nowere the nearest garage that can do it is 2 hrs away
nearest LR dealer is the same
but they wont touch my car cos it was not bought in france it was bought in Italy
and it does not exist on the french LR computer system
had the same problem with the wifes nissan it a 2litre and was bought in spain as 2litrs is not available in france only 1.3 or 1.6
nissan here wont touch it its like that in france
this was the begining of last year and i had a garage vacume it and refill
it lasted all summer
as we are coming now to warmer weather it needs charging again so and so i bought and fitted a new compressor
and now need to refill the system
so i thought after watchin several utube vidios i would do it my self and bought a set of gauges and some cans off the internet
on utube they did as has been mentioned vacumed the system
put the tin on scales and charged the system this difference between the scale at start and finish give you the grams put in
do this with cans untill you have 600 grams accprding to the scale reading
this was to me straight foward
the problem has come about wit the can lable
170g net it says on the can
278 when i put the can on the scales
but on the instructions on the can it states the can is equivalent to 423 grams of gas
there lies the dought !!
Mike
like i said i had i small leak on the compressor
and i didnt have time to do anything
i live in the south fo france in the middle of nowere the nearest garage that can do it is 2 hrs away
nearest LR dealer is the same
but they wont touch my car cos it was not bought in france it was bought in Italy
and it does not exist on the french LR computer system
had the same problem with the wifes nissan it a 2litre and was bought in spain as 2litrs is not available in france only 1.3 or 1.6
nissan here wont touch it its like that in france
this was the begining of last year and i had a garage vacume it and refill
it lasted all summer
as we are coming now to warmer weather it needs charging again so and so i bought and fitted a new compressor
and now need to refill the system
so i thought after watchin several utube vidios i would do it my self and bought a set of gauges and some cans off the internet
on utube they did as has been mentioned vacumed the system
put the tin on scales and charged the system this difference between the scale at start and finish give you the grams put in
do this with cans untill you have 600 grams accprding to the scale reading
this was to me straight foward
the problem has come about wit the can lable
170g net it says on the can
278 when i put the can on the scales
but on the instructions on the can it states the can is equivalent to 423 grams of gas
there lies the dought !!
Mike
Datatek
Well-Known Member
The weight of a gas increases, it's density increases and it's volume decreases as it is compressed, thus expressing the weight of gas is pretty meaningless without also expressing the pressure.
Graculus
Well-Known Member
The weight or pressure doesn't change appreciably in a workshop environment which is usually 15-20 deg. C. obviously it does, which is why there is always a tolerance on the system charge label - anything from +/- 10g to +/-50g dependent upon the size of the system and the refrigerant. R134A has a very different profile to R1234YF which in turn has a very different profile to R410. If you look at practical usage, charging is always done by weight - even for fixed installations which of course will have a wider range of temperature variance, the key point is, that the system, whichever it is, has a correspondingly wide, if not wider, operating temperature range which makes the small variances in a closed system meaningless in the scheme of things.
Most HVAC systems in vehicles since the early 90's (some earlier) work on the reheat principle, that is, incoming or recirculated air is first chilled & dried before being sent through or round the heat exchanger then blended to meet the cabin heating (or cooling demand) what this means is that the aircon is operating continuously, with a device called a thermostatic valve that acts as a flow restriction to compensate for extremes of temperature so maintaining correct operation.
I'm not disagreeing with you, just saying that in the context of a small vehicle borne system, the differences are negligible.
Most HVAC systems in vehicles since the early 90's (some earlier) work on the reheat principle, that is, incoming or recirculated air is first chilled & dried before being sent through or round the heat exchanger then blended to meet the cabin heating (or cooling demand) what this means is that the aircon is operating continuously, with a device called a thermostatic valve that acts as a flow restriction to compensate for extremes of temperature so maintaining correct operation.
I'm not disagreeing with you, just saying that in the context of a small vehicle borne system, the differences are negligible.
Don't forget temperature...
I never got mine done, only local specialist couldn't be bothered to do a proper job, just.. 'hope for the best', which for a system that had an unknown amount of old oil in it and been open for years, didn't sound great
Datatek
Well-Known Member
It only took one can to fill my P38 to the correct low side pressure per the instructions and it worked fine for about 13 years until the performance started to drop off.
Graculus
Well-Known Member
TBH, I'd have given you two options - 'hope for the best' and 'replace the lot'. The reason being that there would be as much, if not more corrosion on the inside of the aluminium components and the filter-drier would be saturated, never mind the corrosion within the compressor...
Yes I'd read that the oil can go acidic off left open to the atmosphere and do untold damage
Compressed gases turn to liquid so for example a litre of liquid oxygen which is -183 degrees will expand to 240 x it's volume as a gas that's why hospitals or any other place that uses large quantities of oxygen/nitrogen/argon or Co2 will have liquid products in storage vessels as they take up less space than the 'bottled' gas equivalent.
