[Dingsey]

Hey guys


Was just wondering if anyone could have a look on there A/C sticker and tell me how many grams of r134a a GQ patrol takes, I need to gas mine up tomorrow and my sticker has fallen off.


Cheers
Jamie

 

[Don]

I cant give you the amount for a GQ but for a GU single air it is 750-850 grams and i can't imagine the GQ will be significantly different

Regards Don

 

[Dingsey]

Thanks mate i thought it would be abit less then that but guess not, cheers

 

[Sparky_GU]

Gas it by sight glass. I wouldn't go over 650 but keep an eye on your head pressure. I'm guessing your qualified to do so??

 

[Dingsey]

Im a 3rd year Fridgey apprentice just havent done much with auto A/C though. So around the 600 mark sounds like a good place to start i didnt think it would take that much but apparently so

 

[Dingsey]

It doesnt have a sight glass usually we gas by amps/superheat on splitys but natural car AC is different what sort of pressure should it be running at?

 

[Sparky_GU]

Depends on alot of factors, temp of day, effiency of the system etc. If no sight glass start at 400g and go from there.

 

[Sparky_GU]

Just looked at temp for hervey bay tomorrow aim for 220-240/30-25 @ 1500rpm with the engine at operating temp and viscous fan engaged.

 

[Dingsey]

Alright thanks for that mate, really helpfull, so just aim for those pressures and then just generally feel how cool it is etc,


I gased it up before but i only put 250g in it and it felt cold then while we were gassing it then i turned it on out 4x4 the other day and it was barely cool. ill reclaim the gas in it now and give it a pressure test with nitro( how high would you go with nitro in a car A/C system? ) then give it a vac out and gas it from there on i guess


Cheers
Jamie

 

[Sparky_GU]

Automotive system must cycle so look for between 4-8 degrees vent temperature. Pressure test to 300psi (not much more the front seal in the compressor doesnt like it) and let it sit for a good half hour. Also give the two rubber lines from the compressor a good bend as if they are suspect will let go under this pressure. Change the drier and from memory it's just a standard number 6 drier so the new one should have a sight glass that will aid in regassing.

 

[Dingsey]

Alright so just chase 4-8 degrees vent temp so almost use that as my superheat reading kinda thing. Thanks for your help mate made it alot clearer what needs to happen

 

[Sparky_GU]

Yeah the compressor should cut out between 4-8 degrees vent temp but it will cycle while the system is still under gassed too. Would gas more to head pressure and gas quantity.

 

[Dingsey]

Yea no worries so try chase about 25/30 pound then 4/8 vent temp will just do it slowly no rush.

Also the connection between one of the flexible hoses i want to check it, should i put oil on it ( the connection itself) like you do with a A/C split flare or just connect it back up bare

 

[Sparky_GU]

No you want to gas by high pressure meaning you should have 220-240psi head pressure and 30-25 on the low side. Initial charge through the high side then top up through the low with the engine running. If you check any connection then you will have to replace the o'ring before re-fitting and yes a bit of oil to stop the o'ring from pinching is a good idea.

 

[Dingsey]

Alright got ya haha, Thanks again will let you know how i go.

 

[Dingsey]

One question though, does it have to be a specific type of O ring ? We have just like general o rings but not sure if it has to be like a high pressure o ring or something liek that

 

[Don]

Depends on alot of factors, temp of day, effiency of the system etc. If no sight glass start at 400g and go from there.

Using a Dial-a-charge covers one of these variables

Regards Don

 

[Sparky_GU]

A dial a charge only gives you gas weight by volume varied by pressure relative to temperature. 400g is 400g measured by dial a charge or a set of scales its still the same. The original post was regarding average system high pressure in relation to temp of the day etc.

 

[Don]

A dial a charge only gives you gas weight by volume varied by pressure relative to temperature. 400g is 400g measured by dial a charge or a set of scales its still the same. The original post was regarding average system high pressure in relation to temp of the day etc.

Sorry

Just read it again & saw what the question was

Regards Don

 

[Dingsey]

Gased it up all good, thanks for the help guys