I'm sure thats the case on Climatronic, the Yeti is a manual system, the Octavia a Climatronic, they both dropped the temp an additional 2° on switching to recirc and both made the same noises from the flaps, it sounds like there is more airflow as if the pollen filter is being bypassed.

 

Note that pressing the recirc button when on auto switches it to manual but I did the testing on MIN which seems to switch off the Climatronic controls.

 

I expected greater than a 2° drop when the outside air was 30°C but maybe they both were already partially recirculating, I probably should have tested for a lot longer because initially the inside air temp would have been hotter than the outside, when driving I can feel the difference but it is not dramatic.

I did a back to back test but it was getting dark, I could not read the guages too well and I didn't record the results.

 

But it looks like the Octavia has less charge than the Yeti (no surprise) the Yeti may not have a full charge because I have had ro recharge it twice before and the guage readings tonight were lower than I have seen before but that could be temperature related, it was cooler than earlier, my watch is showing 23°.

 

Anyway the standby pressures were about 90psi low & high side, the Yeti being probably 10 psi higher than the Octavia.

 

Once the compressor was loaded the Yeti rose to around 175psi before the fan cut in dropping to around 150 psi high side & maybe 40 psi low side (very difficult to read.

 

The Octavia rose slowly, only reached around 160 psi, the fans cut in & it dropped to maybe 140/145 psi, a bit less than the Yeti but the low side was about 10 psi less.

 

Too dark to compare the readings against the charts but it gives a good comparison between 2 partially charged systems, remember that the Octavia cooled to 10°c and the Yeti to around 5°c.

 

After the last recharge the Yeti rose to 200psi quickly before the fans brought it down to 150 psi.

 

I found on the Climatronic system the only way to have the engine running and no activation whatsoever of the N285 valve was to select ECON mode.

Edited 13 August, 20205 yr by J.R.

Here's an informative animation, forget about the electro-mechanical clutch:

 

 

Interesting, what is that block thing that changes the high pressure pumped high side into low pressure into the evaporator?

 

Looks like an orifice into a larger diameter pipe.

The expansion valve, I expect it works similarly to the variable pressure valve on an air compressor, gas regulator and the like but at a fixed setting.

 

I have a hard time comprehending how such seemingly finely manufactured items as the condenser hold such pressures, tried and tested I know but nonetheless amazing.

Edited 16 August, 20205 yr by MicMac

Condensers give the appearance of being super-fragile due to the very fine comb of fins that conduct heat away from the much more robust tubing that actually transports the refrigerant around.

I learned that repairing a crash damaged salvage Sierra in the 90's, hard frontal, new front panel, wings, inner wings, portapower the chassis rails etc.

 

Radiator completely smashed & the aircon condensor in front of it, the first one I had ever seen was bent like a banana, before removing it something told me to push the Schrader valve on what I now know to be the filling port.

 

It was still pressurised 😯

 

I had to leave it hanging out of the way while I repaired everything behind it which was wrecked.

 

I even bent it sort of straight in situ with mechanical assistance without it leaking, the A/C worked fine on start up.