Poor demisting? Any experience

[Ocy_RS_TDi_Kombi]

That can only mean that there's too much moist air inside the cabin, which takes me back to the recirc button setting.

I've found with my car regardless of what the recirculate button is set to, when I turn the A/C on, the car automatically goes into recirculate and fresh mode on its own (you can hear it suck the air from under the passenger side of the dash and then change to fresh when the fan speed is high). I've thought of getting the dealer to look into it but I keep forgetting when I have the car serviced.

[BottomScratcher]

I've found with my car regardless of what the recirculate button is set to, when I turn the A/C on, the car automatically goes into recirculate and fresh mode on its own (you can hear it suck the air from under the passenger side of the dash and then change to fresh when the fan speed is high). I've thought of getting the dealer to look into it but I keep forgetting when I have the car serviced.

Not sure what you mean by "recirculate and fresh mode on its own". When the left light on top of the recirc button is on the unit should be in recirc mode. When the right button is on it's in automatic air distribution mode, which means fresh air is coming into the car until a sensor switches to recirc after contact with high level pollutants, like sitting in a traffic jam, or driving through a long poorly ventilated tunnel. As soon as the senso detects that the air is clean again the recirc is shut off, and fresh air again comes into the cabin. The recirc button only sets recirc mode when the left light is on.

I spent last weekend around the NSW Southern Highlands, and spent more time fiddling with the Climatronic controls than I wanted to. As with domestic reverse cycle A/C systems I don't find the "Automatic" mode of the Climatronic to be to my liking. I prefer to use A/C mode, and set the temp for heating or cooling, so if the outside temp changes due changing altitudes while driving, or I've pulled up and the car has been in the sun for a bit I need to make adjustments then readjust once conditions have again changed. The seat heaters are great, but the Auto mode just doesn't do it for me. If I'm generally comfortable, but say my legs are cold, as soon as I hit the button to direct warm air to my legs the Auto mode is cancelled anyhow. I find it fiddlier, but for my comfort more effective just to use the A/C mode. Just wondering if anyone prefers the Auto mode, and if so why.

[K1W1]

The biggest issue at this time of year is that all cars are damp inside and they tend to be locked up tight when parked overnight and driven with the windows closed which means the moisture condensates on the inner surfaces of the windows as we all know.
The absolute best thing people can do is open the windows at any opportunity and dry the inside of the vehicle out. Days like we have had over the last week in Melbourne are perfect. If your car is parked in the sun somewhere during the day open all the windows an inch (2 cm for young people) or so before you lock it up. Getting the moisture out of the car first goes a long way to stopping the thing condensating overnight.

[dagget]

The biggest issue at this time of year is that all cars are damp inside and they tend to be locked up tight when parked overnight and driven with the windows closed which means the moisture condensates on the inner surfaces of the windows as we all know.
The absolute best thing people can do is open the windows at any opportunity and dry the inside of the vehicle out. Days like we have had over the last week in Melbourne are perfect. If your car is parked in the sun somewhere during the day open all the windows an inch (2 cm for young people) or so before you lock it up. Getting the moisture out of the car first goes a long way to stopping the thing condensating overnight.

Very sound advice there, over the last weekend I left all the cars and car covers outside to dry out. Was quite a sight with 6 cars scattered around doors and windows open drying out and car covers/sheets/old bed spreads on the fences.

Problem is we are cold/damp as we are high up 700m and more likely to get rain given our location the the ranges.

Worst car we had up till now was the old Honda CRV always wet and damp inside but a quick dry in the sun worked a treat. My old Merc 190 was also a bad offender with dam inner windscreen. Hopefully a bit of sun now and again will keep everything dry.

I also added some damp rid to the stored cars to assist in the drying as ordered a couple of rechargeable ones for the Skoda.

They drying seems to work a treat, was -3 this morning and the car frozen shut, but undercover and no problem with fogging.

[wai]

You mentioned cold and damp. Humidity is a big factor, and Hillbilly is spot on with the suggestion to use cold air and recirculate. And I mean cold, as in A/C cold.

It is not that it is cold air that helps demist the windscreen as such, but that the A/C cools the air to something close to 0 deg C, and cold air has a reduced capacity to hold water vapour and so ends up being dehumidified. When it comes in contact with the windscreen at above this temperature, the air warms up and warm air has a greater capacity to hold water vapour, so it "sucks" the water vapour off the windscreen. Cold air saturated with water vapour will have little effect on demisting a windscreen. It has to be dehumidified air.

So, the A/C is an excellent way to demist the windscreen, and it has the added benefit of keeping the AC working in the colder months.

The MAX option for demisting does exactly this. It uses high fan speed and refrigerated air well before the engine temperature has had a chance to get up to have any effect and turns on the A/C.

[BottomScratcher]

So, the A/C is an excellent way to demist the windscreen, ...

Maybe my wording didn't come across right. I agree, which is what I meant when I said "A/C cold", and said earlier, " A/C cold air is often the quickest way to demist in damp, i.e. humid conditions. The cold and very dry air passes over the condensed moisture on the screen and pulls the moisture away leaving it dry and clear."

I didn't think it necessary to explain why A/C air is dry. I thought most here might know that whether outside a house or a car when the A/C is on the external drain tube will be emitting condensate that was present as moisture in the air inside the house or car.

The MAX option for demisting does exactly this. It uses high fan speed and refrigerated air well before the engine temperature has had a chance to get up to have any effect and turns on the A/C.

Yep, "Climatronic also includes a defrost function which can be activated at the push of a button to clear fogged or iced-up windscreens. This directs the full airflow onto the inside of the glass at the highest blower and heat output settings. If the outside temperature is above 0 °C, the cooling system cuts in too to dry the air before it is heated."

Note that MAX only kicks in the Climatronic air above 0C. dagget mentions -3C, which doesn't surprise being on top of the GDR. It's not only cold up there, but the humidity doesn't drop below 90-95% through June and July.

[K1W1]

Problem is we are cold/damp as we are high up 700m and more likely to get rain given our location the the ranges.

We have about 300mm more rain per year on average than you get at Trentham.

Has anybody ever wondered why on a sunny day in Winter many used car yards have all the cars open with the boots and bonnets up and the windows down? Well now you know....

[K1W1]

Maybe my wording didn't come across right. I agree, which is what I meant when I said "A/C cold", and said earlier, " A/C cold air is often the quickest way to demist in damp, i.e. humid conditions.

All European cars since the 1980s have had the optimum settings for demisting clearly marked on the heater controls. These days it's often a push button in the old days it was a correct setting for the levers and knobs. To demist a European car you don't even have to open the owners manual you simply have to open your eyes when you are sitting in either of the front seats.

[wai]

Maybe my wording didn't come across right.

Oops. Did not mean to have a go.

By the way, I recall a friend of mine had a Mitsubishi Magna, and it had a reverse cycle A/C so that you had warm air to warm you and demist immediately the engine started.

[wai]

We have about 300mm more rain per year on average than you get at Trentham.

Has anybody ever wondered why on a sunny day in Winter many used car yards have all the cars open with the boots and bonnets up and the windows down? Well now you know....

When I last had my Caddy serviced (July last year), someone at the dealership (in Penrith) did not close the rear barn doors properly on the loan car so that when I picked it up, there was so much water on the inside of all the glass that it took all day to dry out.

[BottomScratcher]

All European cars since the 1980s have had the optimum settings for demisting clearly marked on the heater controls. These days it's often a push button in the old days it was a correct setting for the levers and knobs. To demist a European car you don't even have to open the owners manual you simply have to open your eyes when you are sitting in either of the front seats.

Horses for courses I suppose. Having spent most of my life working with explosives I'm more of a "Read the manual" type than a - as it gets turned on - "What's this switch do?" type. And an "optimum setting" is greatly dependant on the climatic conditions at the time, e.g. the Climatronic not operating below 0C.

We're a bit slow in Oz. It's not that long ago that we caught on to double glazing our houses. It was never done here because of the attitude that this isn't Europe, so we didn't need it.

The same logic applies to trucks. In Europe trucks have night heaters. An external burner uses a tiny amont of fuel drawn from the main fuel tank to supply warm air to the cab for sleep/rest comfort. They can also be set on a timer, so if left unattended in a yard the heater will come on an hour or so before the driver turns up, so ridding the hassle of deicing windows, and or getting a foot or more of snow off the cabin roof. Seemingly Australian truckies mostly prefer to freeze their rear ends off.

The same with cars. European cars have night heaters as an option. Skoda call it Auxiliary Heating. It's in the book . While working OS. I've had a BMW, and a Range Rover with night heaters, and they're nothing short of brilliant.

I've no doubt that if I lived in Canberra, or anywhere on top of any of the ranges or highlands where the temps go subzero and are mostly below average, and where the winter humidity is mostly higher than average that I'd have ordered one as an option ex-factory when buying my Octy.

[BottomScratcher]

No worries. Written words don't always get taken in the context they are written. Especially the way I can butcher English.

I've heard of a 4-way reversing valve that can be used to convert standard auto a/c to reverse cycle, but didn't know about the Magna.

I've seen it mentioned for caravans, but for cars I'd think demisting at cold start is the only time it would be useful. Once the engine warms up it becomes redundant.

[brad]

Oops. Did not mean to have a go.

By the way, I recall a friend of mine had a Mitsubishi Magna, and it had a reverse cycle A/C so that you had warm air to warm you and demist immediately the engine started.

Octavias have a 1000W electric heater to immediately start warming the cabin while the coolant gets up to temp. One of the best "hidden" features on an Octy.

[brad]

The same with cars. European cars have night heaters as an option. Skoda call it Auxiliary Heating. It's in the book . While working OS. I've had a BMW, and a Range Rover with night heaters, and they're nothing short of brilliant.

I've no doubt that if I lived in Canberra, or anywhere on top of any of the ranges or highlands where the temps go subzero and are mostly below average, and where the winter humidity is mostly higher than average that I'd have ordered one as an option ex-factory when buying my Octy.

When I was doing my apprenticeship we had a Nubian fire tender fitted with a straight 8 Rolls Royce engine. It had an electric block heater & was permanently plugged into a GPO with a quick release extension cord arrangement. It meant that the engine was running reasonably well after 5 minutes use rather than the usual 20 minute warm-up period. Good stuff!

[Tubbs76]

Apart from making sure your glass is kept clean which always helps, could also be your interior filter. I always wondered why my air con was sluggish, demisting, etc.. pulled the interiot filter out and it was so black, like charcoal. put a new one in and wholah... good as gold. air flow much better, stronger, air con heaps colder, air through vents 200% better...HAve you checked it?