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VF vs. ZB Aircon

Overwatch

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Cross post from ZB forum
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Hi y'all...I'm new to this site and joined the forum as Holden and its dealers (surprise) have been unable to assist.

I've transitioned from a VF2 to a ZB (why you may ask-another story-have driven only Commodores for 13 years) and in the VF2, the HVAC was sweet. I could set the dial to a certain temperature, push the aircon button to 'Off' (the Aircon LED light would go off) and the air would still be cool without (I think) the aircon being on, eg. say 21 and it would be 26 outside. If I did press the aircon button to on (the aircon LED would light up), I would hear the compressor starting up and the air would turn from cool to cold.

With the ZB, this no longer happens. If you want cool air, you now always need to have aircon on. It will simply not blow cool air without the aircon on.

My question is what is the difference between the VF2 and ZB HVAC systems that the above happens?

Specifically, how is the VF's aircon designed such that even without the aircon on, it can still supply cool/cold air when the air outside is hot? Of course, depending on how hot it is outside, if you kept turning the dial down, the aircon LED would turn on at some point turn on but I loved the "sweet spot" before this point where you got cool air without the harshness of the actual aircon being on.

Question to Holden ("we're not mechanics here, call a dealer") and to dealers ("sorry, the ZB is new/not built to Aussie conditions/we didn't build it/too new for us to know/not trained yet etc. etc.) were not productive. Suttons City suggested I ask here.

Any advice appreciated, hoping there's an VF HVAC expert here!
 

stooge

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Maybe also try google searching for "insignia" ac issues because thats what the zb is and has been sold as for a fair few years now so you might find more info that way.
 

Forg

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The VF might have been on 'Recircle', where the air it blows around is source from inside the cabin where it's already been cooled.
There have been posts around here recently where people think that even when they've switched their VF's aircon off according to the aircon controls, it was still cooling - may have been what was happening with your car?

As an aside, if we use Auto or we switch on our VF's aircon manually, the LED under the snowflake stays on, regardless of whether the interior has reached the set temperature. It seems to be an indicator that the compressor is enabled, rather than an indicator that it's running.
 

Anthony121

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Maybe the ZB sucks outside air closer to the engine bay instead of in between the windscreen on the VF. I have driven the ZB (and other GM cars) without A/C switched on but I will say you cannot drive without A/C on if outside is 26 degrees as the interior will become very warm very quickly. The user manual does state in the VF that the AC will come on if set to recirculate. Even demist the AC is on even with the snowflake AC button not eliminated. Also I have stated in another post, it also determines if the car is in a tunnel and usually will switch to recirculate and AC on. The ZB should also do that as it can determine a tunnel environment with the sun sensor.
 

Fu Manchu

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We can show you how the HVAC is designed in the VF but it’s complicated in both VE and VF and might not translate to anything meaningful for you.

I don’t think anyone has access to Opel Insignia/ZB manuals yet. They would show the design of the HVAC system and answer the question for you (maybe).

The VE/VF system is a series of compartments that open and close off the heater core.

I recall the VZ’s used a vacuum actuated tap to restrict coolant flow through the HVAC, maybe the Insignia design does a similar thing. The VZ is warmer when it’s on cold than our VE.

I’ve had the whole HVAC in bits on the VE before. Even then it took a few goes getting back together correctly getting my head around how the compartments in it work.
 
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