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Charging Procedure Question

Lextex on Mon September 24, 2007 3:19 PM User is offline

Year: 1998
Make: Toyota
Model: Sienna

I have a general question on charging a system.

If a system calls for 26 oz. of R134A, do I need to overcharge some amount to account for the loss of refrigerant that is trapped/lost in the hoses when they are disconnected? I have read that as much as 4 oz. of refrigerant can be in the hoses.

Thanks

Chick on Mon September 24, 2007 3:23 PM User is offlineView users profile

A couple ounces extra for what is left in the hoses..If using a scale, let the lines fill before zeroing the scale... You have to "judge" if not using a scale, so an ounce either way is no big deal, just make sure the suction line going back to the compressor is cold when you think you have the full charge in..You can't feel the inlet and outlet with the expansion valve system you car uses....

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

mk378 on Mon September 24, 2007 7:10 PM User is offline

After charging, disconnect the high side hose from the car, close the valve on the R134a source, then with the compressor running, (double check high side hose is dosconnected) slowly open both valves on the manifold. Both gauges should read the low side pressure. This procedure pulls any liquid refrigerant out of the gauges and hoses, the amount remaining now is truly negligible.

Chick on Mon September 24, 2007 7:18 PM User is offlineView users profile

Quote
Originally posted by: mk378
After charging, disconnect the high side hose from the car, close the valve on the R134a source, then with the compressor running, (double check high side hose is dosconnected) slowly open both valves on the manifold. Both gauges should read the low side pressure. This procedure pulls any liquid refrigerant out of the gauges and hoses, the amount remaining now is truly negligible.

Just to add, be sure the yellow hose is either closed, or disconnected from the refrigerant source.... But this method is how most of us do it....

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

2POINTautO on Thu September 27, 2007 12:12 PM User is offlineView users profile

I think that procedure would depend on the type of hoses you have, mine do not have schrader valves to close off atmospheric air, my hoses have inserts that push on the schrader valve on the car LO and HI ports but bleed off the hoses to atmosphere when disconnected from the car.

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Give all the dirty details
and dont forget the LO & HI pressures
Year, Make & Model would be nice too

mk378 on Thu September 27, 2007 12:51 PM User is offline

Old R12 sets were like that. A standard R134a set will have isolation valves in the car couplers and on the yellow hose. The law in the USA requires isolation provisions, so anything sold here of modern manufacture (other than maybe the really cheap Chinese stuff) will be built that way.

2POINTautO on Thu September 27, 2007 9:11 PM User is offlineView users profile

Thanks for clearifying, I have both just as you stated, thanks to the member who gave the evacuation of both hoses procedure, after years of doing this its the first time I have heard of the procedure, so the hoses will be drained of their liquid freon and be drained down to about 30 PSI (running LO side pressure) of gaseous freon leaving less waste, thanks.

-------------------------
Give all the dirty details
and dont forget the LO & HI pressures
Year, Make & Model would be nice too

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