Is it possible to charge AC from high pressure side???

[pbear95]

:confused: :confused: :confused:

Howdy All,

I went to AutoZone in Clackamas, Oregon on Wednesday. They said they do not charge AC systems, but had all the supplies to do it yourself - which I already have, I am just a long way from home and it would be nice to have cooler AC. I was also told it is not possible to charge from the High Pressure side with a retail 500ml, 750ml or 1L aerosol can of R134A. There is only approximately 15psi (pressure) in the can.

The only way I am aware of filling from a retail charge can of R134A coolant would be to heat the can over 150 degrees F. Even doing this I don't think it would still be high enough to overcome the High Pressure side of the compressor (the High pressure port marked with 6nm torque spec). It is my understanding you would need over 40 psi or more to overcome the system pressure.

It is also my understanding that even Volvo pull down a vacuum to drain the system from the low pressure side. Then when filling there is a pressure gauge & R134A connected to low pressure side - with only a gauge connected to the high pressure side. They measure the delta P across the system to prevent over filling the system or cracking the pump. They use a professional machine to charge the system, which if I am wrong I am sure it could generate enough pressure to fill through the HP side - if that is in fact where they fill from. Could someone please confirm my understanding is either correct or flawed?

Either way - how does one remove the 6Nm High Pressure Cap??? I have a charge systems with gauges for both sides and would like to try charging the systems. Can anyone confirm what the low pressure & high pressure sides should read on the gauge???

:confused: :confused: :confused:

Thanks,

[RedXC]

:confused: :confused: :confused:

Howdy All,

I went to AutoZone in Clackamas, Oregon on Wednesday. They said they do not charge AC systems, but had all the supplies to do it yourself - which I already have, I am just a long way from home and it would be nice to have cooler AC. I was also told it is not possible to charge from the High Pressure side with a retail 500ml, 750ml or 1L aerosol can of R134A. There is only approximately 15psi (pressure) in the can.

The only way I am aware of filling from a retail charge can of R134A coolant would be to heat the can over 150 degrees F. Even doing this I don't think it would still be high enough to overcome the High Pressure side of the compressor (the High pressure port marked with 6nm torque spec). It is my understanding you would need over 40 psi or more to overcome the system pressure.

It is also my understanding that even Volvo pull down a vacuum to drain the system from the low pressure side. Then when filling there is a pressure gauge & R134A connected to low pressure side - with only a gauge connected to the high pressure side. They measure the delta P across the system to prevent over filling the system or cracking the pump. They use a professional machine to charge the system, which if I am wrong I am sure it could generate enough pressure to fill through the HP side - if that is in fact where they fill from. Could someone please confirm my understanding is either correct or flawed?

Either way - how does one remove the 6Nm High Pressure Cap??? I have a charge systems with gauges for both sides and would like to try charging the systems. Can anyone confirm what the low pressure & high pressure sides should read on the gauge???

:confused: :confused: :confused:

Thanks,


I rather suggest you not to charge your HVAC system yourself. There are many reasons why! Some "can" size R134a is blended which can be flammable, and if there was a leak from the evap or somewhere in the interior, with high temperatures, the leaking blended refrigerant can explode and shatter your windows. The only refrigerant known to be safe by the EPA is HFC-R134a. Each time the shop or dealer service the A/C system, they are to recycle the oil in the compressor, and inject with PAG oil. To charge A/C is both high and low system fittings, on some older volvo there are only low side fittings. I am not sure about the new volvo, i havnt actually take a good look at the system. but you have to charge with both low and high side together. sometimes a overcharge and undercharge a/c system will not be cold.

high side should not go over 350psi while adding refrigerant, if its higher, stop adding refrigerant and let it stabilize, if it does not stable, spray water on the condenser to lower pressure.

To open the 6Nm cap, a 17 or 19mm deep socket will do. but when tighten, be sure to not over tighten it. I strongly suggest you to have a professional to recharge/recycle your system. Your cooling will be better and normal operating.

A/C Compressors should be often lube, so turning on your a/c system will help lube the compressor which will expand the life of your compressor.

[RedXC]

Here are the pressures while the HVAC system is on.

Normal Operating Pressure
LOW SIDE: Between 21-35 psi

HIGH SIDE: Between 190-220 psi

* that is ambient temperature at 80 degree F.

[dfuerst]

Just a quick question, where are the high and low pressure ports on the XC70?

Darren

[RedXC]

Just a quick question, where are the high and low pressure ports on the XC70?

Darren


the low side fitting is near the hood latch. the high side, I have to get back to you. But if you follow the smaller diameter hoses, you should find it. maybe its at the compressor.

[dfuerst]

Thanks!

Darren

[Art]

Just a quick question, where are the high and low pressure ports on the XC70?

Darren

The location of the HP port is near the front of the engine and is clearly labelled ‘Refrigerant Under Pressure’. The LP port is just off to the right of the power steering fluid reservoir.

http://volvoxc.com/volvo_photo_gallery/albums/userpics/XC%20Refrigerant%20Ports.jpg

[RedXC]

^ oh thanks for the info!!