What is the total weight of 134A in the dash ac system for a 40' U320 2003?
A friend of mine is coming over tomorrow and will vacuum out the system and refill.
I read one post that indicated 5 to 5.2 lb.
Thank you
Can you give FOT a call? It might be on a label somewhere on the system components.
Fill by PSI/gauge readings.
Do what Brett says.
I couldn't get the pressures to match what r-134 should be on both the high and low side. Put a thermometer in the register in the dash and charged until temp dropped to 40 deg. and ignored pressures. I know something isn't right but cannot find a restriction so went with if it works leave it alone.
We have a gauge set, but find the best way is to add refrigerant until dash feels cold and/or have thermometer in dash outlet.
Have a permanent dash thermometer with a wired sensor probe that is placed inside dash plenum, a few inches from evaporator coil.
We see temps about 38 degrees at the evap coil.
38 deg is incredible. Outside air temperatures, inside temperature affect everything. If you are seeing 40 deg drop from inlet to evaporators to outlet you are doing real good. 134 can be easily overcharged and perform poorly. I charge by temperature drop and seek to stop at the peak. Many factors affect performance.
Scott
The air inside is the factor as it is on recirc usually. Works like a big refrigerator keeps getting the output returned. If you put the dial on fresh air you would be trying to cool the outside air and never get to the 40 deg. I get.
You can also look at the sight glass on the dyer. Most have black tape over the sight glass that you will have to remove. Add till no bubbles are seen, wait a week and re check if you are losing 134a
Our experience is sight glass is not useful for R134A and not included in new filter-dryer.
Should be able to call FT and get the exact charge weight. 134A doesn't like to be over charged head pressures will go sky high, to low the system will go into a vacuum. Also if you replace components like the dryer you will need to add PAG OIL.
5 pounds was std