Air Conditioning help
Discussion
Hi PH People.
I am looking for some advice. The air conditioning in my TVR has just been recommissioned and is holding pressure fine but it only blows really cold for a short period, sat 5 to 10 mins and then warms slightly for quite a while and then cools down a bit and continues like that unless you switch it off. If switched off for a bit and then on again it starts the cycle again.
The question is how do I get it cold all the time? Is it likely overfilled or underfilled. The only air conditioning specific tools I have is the top up set from Halfords so rudimentary at best.
The car is a TVR Cerbera and before the condenser getting holed a while ago it blew properly cold.
I am looking for some advice. The air conditioning in my TVR has just been recommissioned and is holding pressure fine but it only blows really cold for a short period, sat 5 to 10 mins and then warms slightly for quite a while and then cools down a bit and continues like that unless you switch it off. If switched off for a bit and then on again it starts the cycle again.
The question is how do I get it cold all the time? Is it likely overfilled or underfilled. The only air conditioning specific tools I have is the top up set from Halfords so rudimentary at best.
The car is a TVR Cerbera and before the condenser getting holed a while ago it blew properly cold.
GreenV8S said:
gruffalo said:
The air conditioning in my TVR has just been recommissioned
Have you asked the people who recomissioned it? This sounds like the sort of problem that should be very easy for a specialist to resolve.If it is going warm then cold etc is that not because it is controlling the temperature as it is supposed to?
Try setting it to whatever minimum is and see if it stays cold.
Other than maximum or minimum the temperature control takes over to keep the temp within a few degrees of the desired setting.
Unfortunately all control systems by definition have an upper and lower switching point, so in an old style electro mechanically controlled system 19 degrees may well be controlling between 17 & 20 degrees. More modern electronic controls will likely keep this well within 1 degree.
Try setting it to whatever minimum is and see if it stays cold.
Other than maximum or minimum the temperature control takes over to keep the temp within a few degrees of the desired setting.
Unfortunately all control systems by definition have an upper and lower switching point, so in an old style electro mechanically controlled system 19 degrees may well be controlling between 17 & 20 degrees. More modern electronic controls will likely keep this well within 1 degree.
E-bmw said:
If it is going warm then cold etc is that not because it is controlling the temperature as it is supposed to?
Try setting it to whatever minimum is and see if it stays cold.
Other than maximum or minimum the temperature control takes over to keep the temp within a few degrees of the desired setting.
Unfortunately all control systems by definition have an upper and lower switching point, so in an old style electro mechanically controlled system 19 degrees may well be controlling between 17 & 20 degrees. More modern electronic controls will likely keep this well within 1 degree.
Thank you, it is an old on or off type system with the temp setting controlled by a box that has never been adjusted and once set is set for life, it seems the temp control is factory set and fixed.Try setting it to whatever minimum is and see if it stays cold.
Other than maximum or minimum the temperature control takes over to keep the temp within a few degrees of the desired setting.
Unfortunately all control systems by definition have an upper and lower switching point, so in an old style electro mechanically controlled system 19 degrees may well be controlling between 17 & 20 degrees. More modern electronic controls will likely keep this well within 1 degree.
I will test for the high pressure being around 10 bar in the morning, I am told this would be about right.
THe system has a pressure switch which will cut out the compressor if the pressure drops to low or goes too high.
Its the high pressure that could be cutting out the system possibly due to low airflowacross the condenser, have you checked if the fan is running when the ac is on. It may just cut in and out with the ac stat or may be on if the ac is on also driving at over 30 mph should keep a good airflow across the condenser.
Buy youself a set of gauges and monitor the pressures as it is running and you can see if the pressure is getting too high. I had a car regassed and they put far too much gas in and it did the same thing, I like to do my own repairs so got some gauges and had a look myself.
Its the high pressure that could be cutting out the system possibly due to low airflowacross the condenser, have you checked if the fan is running when the ac is on. It may just cut in and out with the ac stat or may be on if the ac is on also driving at over 30 mph should keep a good airflow across the condenser.
Buy youself a set of gauges and monitor the pressures as it is running and you can see if the pressure is getting too high. I had a car regassed and they put far too much gas in and it did the same thing, I like to do my own repairs so got some gauges and had a look myself.
Thanks for all the help I think I have now gotten to the root of the issue.
I seem to have a leak but only when the system is running so hopefully an easy to reach 'O' ring or something.
Vacuum test passes fine and it hold gas until used and then it losses it's charge slowly over time, 6 hours and it is empty. I have now found someone who will pressurise the system with Nitrogen and use a sniffer to go round the system to find the leak so it can be repaired and re gassed.
I seem to have a leak but only when the system is running so hopefully an easy to reach 'O' ring or something.
Vacuum test passes fine and it hold gas until used and then it losses it's charge slowly over time, 6 hours and it is empty. I have now found someone who will pressurise the system with Nitrogen and use a sniffer to go round the system to find the leak so it can be repaired and re gassed.
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