Electric cabin heater

Hi,

I'm coming at this from the absolutely pragmatic "I need heat in here ASAP" that comes with living in an area where -10 is a daily occurence for two-three months of the year and we used to hit -30 at least once per winter.
That there is a finite amount of heat coming from the engine is true, I'd missed that. However, I'd be very surprised if you can tell the difference between leaving the heat off (which will mist the windscreen, which, at least here, tends to freeze then) so for me it's a theoretical point. May make a difference, I'm not prepared to prove it either way. Just leaving it at "21" is also not an option when you actually need to demist the screen; start the car, HI, 3 bars, up, get out, brush snow, by the time you get back in it's probably above zero. The air flow is so slow if you leave it on auto that there's no way it would clear the screen. Yes, ice on the inside.

I have a theory on the real reason the climate buttons wear? Hand cream. Females with handcream use melt it off.... mine are fine and I change the temp all the time in the winter.

That the heater puts more load on is clear. But you have a 120A alternator regulator on a 75, possibly a 140. At that, with cold temperatures, I'd be really worried about emptying the battery extremely quickly, load or no. Especially short journeys would just kill it. The fan motor is also not exactly a small one.

The logic Steaman and Spike posted is pretty clear: for the PTC to be turned on, ALL of the following need to be true; ECON off, <70C coolant temp, <6C outside, >600rpm, and less than 60% alternator load. Since that will essentially never be true (after a start, the alternator is not going to be only 60% loaded!) then I wouldn't be surprised if it's essentially never on. I suspect the alternator load is to avoid it deep-discharging the battery.
Re-reading, the test procedure seems to be to make sure something actually happens, whereas in real life the "HI" or no is not relevant. That would fit with the understanding that the PTC is a straight replacement for the Webasto, which could keep running permanently if necessary.

- Bret
 
If the screen is misted you don't leave it on 21 or Auto, you switch on the screen demist.

The flow of air, even before it has heated up fully, helps remove the inside moisture and the air-con removes a lot of the moisture, always ensure that the air con is switched on when a car is misted up.

As for the climate button wear, are you sure you have soft touch, it was not used in the early (20021/2002 cars I believe)

I am not sure that you can generalise and say that females use hand cream and males don't.

Not all females use handcream of course and slippy hands when driving is not a great thing.

I would be more inclined to believe that long finger nails contribute to the wear. But as I said I VERY rarely touch the climate controls (apart from the screen defrost and rear screen heater in the winter) So cream or not, nails or not, my buttons shold stay fine for a long time.

Steve B
 
Bret,

Respect for living (and driving) in a climate with proper cold weather although we did have a couple of days in January this year when the temperature was ~-10degrees!

Would surprise me if Audi would install a system that was 'essentially never on' but I will do some more investigation at the weekend.

Simon.
 
I'll include in this thread - talking heaters.

What does the Winter Pack when specified new comprise of?

Mirrors, washer jets, seats? anything else?
 
winter pack was heated mirrors and jets, nothing else. the jets are just connected to engine on plus, nothing else.

re handcream / soft touch; I have soft touch, I've scratched it mildly. Seriously, I'm of the opinion that the very alcohol-based solution that allows creams to be applied will dissolve the soft touch paint.

Re "essentially never on" - the 60% alternator load is the bit which I think will rarely be fulfilled. If a cold start = 10 seconds @ 2kw - glow then start...that gives around 0.5Ah load per start. I assumed it was more than that. Would be interesting to map out load on a normal start, cold (-10) and horrendous (-25).

aircon is also off below 5C, so cannot help reduce humidity at that point.

- Bret
 
sco said:
That is interesting - that last sentence suggests there could be some cars that have both diesel and electric heaters.

Looks like there is a relay for the heater on the engine bulkhead and the control unit is part of the heating element - how easy is it to get to that lower part of the air-con unit in the passenger footwell?

Simon.
Click to expand...

Youl need to remove the hole dash and alloy support brace im affraid simon, The unit is built in such a way that complete removal is the only way to seperate , or get at any of the internal parts inside the casings.

Gary



bretti_kivi said:
... and putting cardboard in front of the radiator to help move the warming up process along doesn't seem to work unless it's seriously cold. At UK temperatures it won't help.

- Bret
Click to expand...

I wouldnt advise putting anything infront of the front rads if you'v got climate, and id suggest making sure all the rads fins are clear of gunge, , covering the air con rad makes the unit have to work so much harder as it uses the airflow accros the fins to be able to work, and blocking these puts the system under undo load.

When u select windrsceen defrost, top left on AC , youv got increased air speed and partial aircon sucking the moisture from inside the car, Setting to HI does not affect the speed of warmth, justs increases the percent of aircon to remove more cold air from the cabin, inturn warming up. so infact it does warm up quicker, or even cool up depending where you are.

Gary
 
...but the air con compressor is off at <5C.

Experience - I've been here 10 winters already - says an effective way to do it is to set the climate to HI, up, and two-three bars of fan. No more. Demist doesn't help because the ice on the inside needs melting first and the friction of the air isn't fast enough to affect. Since the water also frequently re-condenses on the outside, the faster the warm air appears, the better. But that's why I have an engine block heater :)

- Bret
 
... and a learning from this morning. My temperature flap was wrongly-positioned, so I was getting no hot air at all. Driving to the garage to go fix it, the fan speed increased (21C and Auto) automatically as the engine warmed. But - the key learning here - the temperature wasn't increasing.
So the Climate is looking at the temperature in the car and the engine temperature, and NOT the temperature of the air coming out of the vents. Moving the flap to the correct position and then running a basic adjustment (group 001 in HVAC, hit "go") means I now have working climate again.

- Bret
 
I've said it elsewhere: yes.

Correctly functioning Thermostats should give heat within 5 minutes at anything over -20 or so in a petrol.

- Bret
 
bretti_kivi said:
I have a theory on the real reason the climate buttons wear? Hand cream. Females with handcream use melt it off.... mine are fine and I change the temp all the time in the winter.
Click to expand...

Some people have relatively very acidic sweat, which can cause similar problems with computer keyboards etc.

RAB
 
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