Astonishing what you learn! (Heater controls)

[poprock]

I have a feeling we're all agreeing with each other but describing it differently.

The way I understand it, the vertical slider on the dash opens and closes flap 5 from the Clark's Garage diagram, allowing air to the windscreen for demisting.

The bottom horizontal slider controls flap 2, allowing air to be directed to the footwell.

The main 0-4 knob controls the blower directly.

The temperature knob controls flap 3, allowing warm air into the flow.

This leaves the top horizontal slider, the one we're still potentially disagreeing about. By the process of elimination it would seem to control flap 4 "¦ but the diagram shows that only affecting warm air, not cold. I'm pretty sure it affects both"”after the warm and cold have been mixed at flap 3.

 

[zcacogp]

Poprock,

No, I think that is where we differ. Flap 5 is called "Defrost Flap". And in the picture of the controls (which I meant to put into one of my posts on the last page - sorry, I forgot) the top slider is called "defrost slide switch". I think that the top slider therefore controls flap 4, and opens or closes the windscreen vents.

The arrow of air coming out of the vent below flap 4 is mixed (hot and cold), and I think this is the face vent. Which can be shut off by the vertical slider, which is mechanical (not servo operated.)

Therefore there are three sets of vents, all of which are opened or closed by their own control.

1. Footwell vents. Controlled by the lower slider.
2. Windscreen vents. Controlled by the upper slider. (Also called "defrost flaps" controlled by the "defrost slider.")
3. Face vents. Each individually controlled by it's own slider (the vertical, mechanical slider in the middle of the central vent to control the central vent, and the smaller sliders on the side vents, respectively.)

Let's see those pictures again. Heating system:

And the controls:

I think this is what Rob is saying, and I think I agree with him. (But I could be wrong on either one or both of those assertions!)


Oli.

ETA: The vertical slider on the face vent isn't featured on the system diagram above, and while it appears in the photo of the controls it isn't labelled or mentioned.

 

[Diver944]

Oh gawd. That's it, I'm selling all my cars and buying a horse and cart []


I can't believe this has been the biggest post of the day [&o]

 

[zcacogp]

Hmmm. OK, so you're sitting on your cart, just behind the horse. What do you think will occupy the same field of view as the face vent does in your S2? (Hint: It may blow stuff in your face.)

[]


Oli.

ETA: 'Nother problem I have thought about with the horse-and-cart plan. It will be even slower than a turbo!

 

[poprock]

I'm going to sit and fiddle with that top slider for ages next time I sit in the car. My wife is going to think I've gone mad.

 

[robwright]

OK I have just driven home with both the now named 'defrost flap' as per porsche diagram and footwell flaps completely closed i.e. fully to the left with gallons of air pouring out of the centre vent in the middle of the dash above the heater controls. Surely that is point proven or has everyone lost the will to live by now????? [8|]

 

[TTM]

We definitely need a video showing a flow bench giving actual, real time measurement of air flow through the vents in function of the position of the sliders. If the flow per vent isn't proportional to the position of the corresponding slider then let's file a case.

 

[poprock]

It's certainly given Oli something to do while staying with the in-laws.

 

[Mike_Pollock]

Anybody know about the earlier cars "system"?
Mike
Loging Off now!

 

[MRGT]

ORIGINAL: TTM

We definitely need a video showing a flow bench giving actual, real time measurement of air flow through the vents in function of the position of the sliders. If the flow per vent isn't proportional to the position of the corresponding slider then let's file a case.

My head hurts [&:]

Howard

 

[garyalanlane]

Just found that out for my self a little while back. Had a new air con compressor and re-gas. I had both levers fully to the right hand side but didn't feel like the air con was blowing cold enough. Had everything checked for leaks etc and found every thing to be fine, so put it down to that's just how it is. It even used to blow out warm every now and again driving me mad. Well I took it out a few weeks ago on a very hot day and as usual I thought this air con is rubbish.....! for some reason I pushed the levers to the left and low and behold lovely cold air con, even with the fan on one or two. over a year that took me to work out....dah

 

[robwright]

I have a new compressor on it's way from the states mate. $186 + $60 posting. I figure even if I get bummed for import tax it still works out less than half the price of getting a new one sorted in the UK. I have a new receiver dryer coming as well at areound £43 from eurocarparts. That way I can now convert the wholesystem to r134a. Did you replace both and do the same mate? Would like to know as I don't think there are too many guys on here that have delved to far into the air con and being the skin flint that I am I always plan to do as much as I can before I have to get the pros in. I.e I only plan on paying for the regas.

 

[zcacogp]

ORIGINAL: robwright
OK I have just driven home with both the now named 'defrost flap' as per porsche diagram and footwell flaps completely closed i.e. fully to the left with gallons of air pouring out of the centre vent in the middle of the dash above the heater controls.  Surely that is point proven or has everyone lost the will to live by now????? [8|]

I did just about exactly the same. And played with the "defrost" button as well, with my fingers over the windscreen vents.

I came to exactly the same conclusion. The top slider controls ONLY the windscreen flaps. And every control on the system turns a set of vents on or off; no control switches flow between vents. Any increase in flow out of one vent when another is closed is purely due to there being more air available to flow out.

Case closed. (For anyone who still cares, and isn't driving a pony and trap [].)


Oli.

 

[robwright]

Trust me mate I didn't spend all that time upside down squeezed into the footwell to let it go just like that lol. Moved and pressed every button to see what goes on after various problems []

 

[poprock]

Well, there you go. I've learned something today. I'm still going to play with all the controls myself until I'm totally satisfied, of course "¦

No time to go anywhere in the car for a few days yet though, I'm too busy putting TIPEC's August magazine together.

 

[robwright]

ORIGINAL: poprock

Well, there you go. I've learned something today. I'm still going to play with all the controls myself until I'm totally satisfied, of course "¦

No time to go anywhere in the car for a few days yet though, I'm too busy putting TIPEC's August magazine together.

Mate if it were me I would be outside right now []

Actually it may even be cooler than my house at the minute

 

[zcacogp]

ORIGINAL: poprock
No time to go anywhere in the car for a few days yet though, I'm too busy putting TIPEC's August magazine together.

I have a suggestion for an article in the magazine ... the ins and outs of the 944 heating system. Just cut and paste this thread ...


Oli.

 

[poprock]

Ah, wrong club though. I'd get in to all sorts of trouble. If you'd like to go repost it all on the TIPEC forum, then maybe "¦

(I'm kidding. Probably.)

 

[zcacogp]

Change the usernames. All will be fine.

(Can you give me a really cool name. Like 'Big Boy' or 'Handsome' or something. 'Ace' * would do ... )


Oli.

* - Any Red Dwarf fans in the house are cordially invited to keep quieter than mice.

 

[robwright]

ORIGINAL: zcacogp

Change the usernames. All will be fine.

(Can you give me a really cool name. Like 'Big Boy' or 'Handsome' or something. 'Ace' * would do ... )


Oli.

* - Any Red Dwarf fans in the house are cordially invited to keep quieter than mice.

Yeah right as if we would. Change your signature to Ace Rimmer from now on Big Boy!!!!