Author Topic: Aircon not working  (Read 3131 times)

culzean

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Re: Aircon not working
« Reply #15 on: August 10, 2020, 10:47:47 AM »
Hi Vic,

I was planning to buy a can and also a pressure gauge and follow some of the  youtube videos i.e. start the engine, set ac to max and cold setting, open the low pressure valve, shake the can connect it, watch it needle move from green to blue whilst also shaking the can etc. 

Still dont recommend?

The gas bottle is £60 ( you get £10 back if you return a bottle when buying a new one ) and another £25 to £40 for the screw-on trigger unit....

If you are not Au-Fait with aircon systems and the system is so low on gas that the compressor won't even run I would definitely go the re-gas route.... The bottles are OK for checking pressure and keeping system topped up as modern gasses seem to leak more easily than older ones,  Personally I would get a regas and start from scratch with the knowledge that the system will then have exactly the correct amount of gas in it.   If you buy a cheap trigger / pressure gauge they really  can be a chocolate teapot...
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

u587162

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Re: Aircon not working
« Reply #16 on: August 10, 2020, 05:07:25 PM »
I have an aircon test with Halfords tomorrow morning, will get it checked there first.  Thanks.

Jocko

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Re: Aircon not working
« Reply #17 on: August 10, 2020, 06:13:49 PM »
Let us know how you get on.

u587162

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Re: Aircon not working
« Reply #18 on: August 10, 2020, 07:54:17 PM »
FYI Jocko - I have the exact same car as in your profile pic.  What is it with blue honda jazz 2006-7 DSI?  I see them everywhere.

Jocko

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Re: Aircon not working
« Reply #19 on: August 10, 2020, 10:42:13 PM »
I think it was the most attractive colour of that series, and as such, popular.

u587162

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Re: Aircon not working
« Reply #20 on: August 11, 2020, 10:32:17 PM »
Hi

So had the car checked by Halfords today, the pressure reading was showing half in the white zone (low pressure / empty).  He topped it up to the threshold of green and red and now got the cold air working again.  However, despite driving some 5-6 miles today, I cant honestly say it is as crisp cold as it was 2 months ago. 

Cost me £45 (£50 less NHS 10% discount).

equaliser

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Re: Aircon not working
« Reply #21 on: August 11, 2020, 11:23:47 PM »
That's good news! It might just be the hotter weather, once the temps get back down you might find it better. No problem with high temps up here, as the weatherman says "except for viewers in Scotland" :)

culzean

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Re: Aircon not working
« Reply #22 on: August 12, 2020, 07:58:14 AM »
Hi

So had the car checked by Halfords today, the pressure reading was showing half in the white zone (low pressure / empty).  He topped it up to the threshold of green and red and now got the cold air working again.  However, despite driving some 5-6 miles today, I cant honestly say it is as crisp cold as it was 2 months ago. 

Cost me £45 (£50 less NHS 10% discount).

With the recent temperatures above 25deg C ambient the aircon may not blow proper cold,  it is a balance between fuel usage and coldness .... some of the older car systems would blow icy even in heatwave but they had a pump that took 5hp off the engine and better gas ( the stuff that was destroying the ozone layer so they banned it ).
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

Jocko

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Re: Aircon not working
« Reply #23 on: August 12, 2020, 09:56:11 AM »
Just before the system finally fails, the low gas pressure leads to greater cooling, hence why it felt so chilly a couple of months ago. Also, the cooling effect depends on the outside temperature and if that is exceptionally high the cooling will not reduce the temperature as dramatically. As culzean says, you can get bigger, more efficient compressors, and manufacturers fit these for sales in hot climates.

TnTkr

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Re: Aircon not working
« Reply #24 on: August 12, 2020, 12:33:14 PM »
Just before the system finally fails, the low gas pressure leads to greater cooling, hence why it felt so chilly a couple of months ago. Also, the cooling effect depends on the outside temperature and if that is exceptionally high the cooling will not reduce the temperature as dramatically. As culzean says, you can get bigger, more efficient compressors, and manufacturers fit these for sales in hot climates.
Exactly, and in addition the humidity affects the cooling effect too.

One anecdote from more than one decade ago. We had a second, partially redesigned prototype of a bespoke AC system from an UK company. We were doing the system commissioning according to manufacturer's instructions. The amount of refrigerant appeared much bigger than in first prototype so I asked them to double-check if the value was correct in kgs. "Yes, the amount is correct." they replied. After charging the system we switched the system on and got immediate slip of the multi-rib belt. After tightening the belt we tried again and got engine stalling. It was a 12-litre truck diesel, so we knew there is something wrong but tried again with higher rpm. Now with belt still slipping there was refrigerant spraying from many connectors in the engine bay. At this point it was obvious that something really was not right, so I called to system designer, told what happened and asked again about the amount. "Yes it should be correct, but let me re-check the calculations" he answered. After about ten minutes he called back "err... the value was for lbs, I forgot to make the conversion to kgs, just changed the unit." So we had more than double amount of refrigerant in the system. Amazingly nothing in the system really broke and after evacuating excessive refrigerant the system worked fine and we didn't got any problems during later months and years either.

Jocko

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Re: Aircon not working
« Reply #25 on: August 12, 2020, 01:37:52 PM »
There is a story of an American movie star who had a considerable mansion. It was designed by a French architect in centimetres - and built by an American builder, in inches.

TnTkr

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Re: Aircon not working
« Reply #26 on: August 12, 2020, 01:50:25 PM »
Only after years I have been realizing the fact that as we didn't blow up evaporator, condenser or compressor, the system was overdimensioned.  We could have saved some size and weight by using higher pressure in the system. But at that time I was just happy to get the system working and still too unexperienced to realize the potential and set demands for the system manufacturer.

culzean

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Re: Aircon not working
« Reply #27 on: August 12, 2020, 03:18:33 PM »
Only after years I have been realizing the fact that as we didn't blow up evaporator, condenser or compressor, the system was overdimensioned.  We could have saved some size and weight by using higher pressure in the system. But at that time I was just happy to get the system working and still too unexperienced to realize the potential and set demands for the system manufacturer.

May be better to have a system working at lower pressure and larger than needed as long as it isn't in an aircraft where weight is at a premium..... lower pressures mean less stress on components and less chance of leaks. Better to have an over-dimensioned system with some spare capacity than a system that is running on the edge of its capabilities..
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

culzean

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Re: Aircon not working
« Reply #28 on: August 12, 2020, 03:25:44 PM »
There is a story of an American movie star who had a considerable mansion. It was designed by a French architect in centimetres - and built by an American builder, in inches.

When designing stuff we were always told to use only metres and mm,  and that cm was not a recognised unit. There is too much chance of confusion if you start using cm. We were always told on CAD always to design stuff full size and not scale drawings,  we used to get other people files come in that we had to import into our designs and sometimes they had been scaled and were pretty much unusable as often they looked tiny compared to rest of the ( full scale ) drawing.
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

Jocko

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Re: Aircon not working
« Reply #29 on: August 12, 2020, 03:31:46 PM »
I never understood why schools teach centimetres and the whole of engineering and industry use metres and millimetres. Mind you; I started in engineering when "thous" were the norm.

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