question about A/C self adjusting orifce tube

hey i just picked one up do we have to use the optional adapted for this and which way do i install this

The long screened end faces toward YOU not the evap when you install.

They work pretty darn good in hotter climates with converted cars.

cool thanks next question in 80 degree weather what pressure am i looking for in the ac system 45-55

I hear they do good. I converted mine and when it was 95-100* outside I had duct temps in the low 30's

thus far its going pretty good dont have a thermometer but its getting cold

i think i need another can its sitting at 40 psi? and i thought i read it should be about 45

depends on ambient air temps. theres a chart as to what psi to outside air temp. I'll see if I can find it.

Found one

http://www.idqusa.com/faqs.php?faq=91&faq_id=91&category_id=7

Charge by your high side and ambient temp, not low side.

With a VOV or variable orfice, the name does as it implies, it changes the orfice size to maintain evaporator saturation which means you can OVERCHARGE and your low side stays the same. Its the same thing for expansion valve vehicles.

40 psi is what i like to see on a 90 degree day on the low side.

35-40 / 225-245 on a r134a vehicle. 245 is TOPS, anything really over that and its gonna chew compressors up and vehicle cooling is impared.

With a VOV , you can use a the charts as a rough guide at best. and yes, expect to see higher charge figures on the low side. These things change teh pressures around and teh balance in teh system is all haywire so normal charts are pretty worthless and going by temperature works best by charging till it wont get any colder. When teh system starts to reach an overcharge point it will begin to run warmer instead of colder. That is you balance point. Keep adding slowly and you will continue to get reduction in temps at the ducts . when teh duct temps stop dropping, stop adding, that simple

that was my thinking acually its pretty cold now no thermo right now but im only at 40 on a 80 degree day on the low side i think it could get colder im not complaining anything is better than no ac

how much refrigerant did you put in? I'm not sure what these take but it should say near the latch..

RLDSL said:

With a VOV , you can use a the charts as a rough guide at best. and yes, expect to see higher charge figures on the low side. These things change teh pressures around and teh balance in teh system is all haywire so normal charts are pretty worthless and going by temperature works best by charging till it wont get any colder. When teh system starts to reach an overcharge point it will begin to run warmer instead of colder. That is you balance point. Keep adding slowly and you will continue to get reduction in temps at the ducts . when teh duct temps stop dropping, stop adding, that simple

Click to expand...

This is a person who has installed more than a few VOVs. He hit it right on the head. about how to charge on of these. In a normal vehicle with an expansion valve or normal orifice tube I charge by weight using a scale. Anytime I use a VOV in a vehicle just as RLDSL said keep bumping it till it starts to get a little warmer. I've got a couple small digital thermometers I'll stick in the ducts to keep checking till it starts to go up instead of down. My service truck right now in 105 degrees temps is blowing 38 degrees out of the vents.

Brimmstone said:

This is a person who has installed more than a few VOVs. He hit it right on the head. about how to charge on of these. In a normal vehicle with an expansion valve or normal orifice tube I charge by weight using a scale. Anytime I use a VOV in a vehicle just as RLDSL said keep bumping it till it starts to get a little warmer. I've got a couple small digital thermometers I'll stick in the ducts to keep checking till it starts to go up instead of down. My service truck right now in 105 degrees temps is blowing 38 degrees out of the vents.

Click to expand...

Is that on max cooling with fan on high? And what refrigerant?

Yep, although I don't turn it down all the way normally. I have to work outside in this heat so I try to not use AC till the day is over and I'm on the way home otherwise I die at work. It's got 134a from Sams Club. I do all my charging from a 30lb cylinder and always draw a deep vacuum before recharging. There is nothing in my system besides oil and refrigerant. Remember I work on tour buses that the AC in has to work perfect otherwise the company looses money and I get my butt chewed. The right gear makes a world of difference when doing AC work. My gauges are top of the line and normally used in commercial HVAC work. My vacuum pump is the biggest Mastercool two stage I could find. It will pull a bus system down to 30 inches in about two minutes. This sounds like a while but our buses use 24-30lbs of 134a depending on the unit. For most people the cheap little ATD kit in a bag will be fine but you will never get the best results with it.