# Air conditioning Q's inside

**URL:** <https://forums.speedlife.net/t/air-conditioning-qs-inside/15616>\
**Category:** NYSpeed Automotive\
**Created:** [August 7, 2006, 11:52am UTC](https://forums.speedlife.net/t/air-conditioning-qs-inside/15616 "2006-08-07T11:52:42Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![Fry](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/fry/32/7284_2.png) [@Fry](https://forums.speedlife.net/u/Fry)\
**Post date:** [August 7, 2006, 6:51pm UTC](https://forums.speedlife.net/t/air-conditioning-qs-inside/15616/7 "2006-08-07T18:51:52Z")

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> [@mike125k](#):
>
> Ball park numbers for R134a…
> 
> High side: 175psi  
> Low side: cycle between 30-45 psi (depending how good the compressor is)
> 
> Keep in mind these are just ball park! Look them up in the service manual for your car. If your high side pressure is low (usually around 75-100 psi) the pressure switch will not cycle the compressor so it avoids damaging itself.

Thanks guys. Sometime soon I’ll look and see if I’m in the triple digits on the high and double digits on the low. If things look low then I’ll probably fill it up, then monitor the pressures over a couples days, then week, then month. Hopefully it’s been leaking since it left the factory and took 5 years to hit the low set point.

I’ve never topped up an AC system. I’m guessing I fill the low pressure side, run the system, and check again?

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