No air from vents

[Seat0510]

Hi.
I have a strange problem on my seat leon fr 2016 1.4 act tsi (great car by the way 210000 km with no serious problems except this one)
I aplogize for my bad english.
So the thing is.. In spring/summer when temperatures are a bit higher I have a problem that my air is not comig through the vents.

When I drive for a while, there is constant decrease in air Flow from vents, from Max to zero.. So then I click ac/Max and all you can hear is blower motor is spining on Max in glove box, But no air is comig through vents, it is quite frustrting because it gets very Hot in car.
So the only thing that helped so far is that I stop some where turn off car and wait for 5-10 minutes and it works normally for some time.
I went to my mechanic he pluged it on computer But there is no error, it looks like there is some flap is closed. He changed one of the termostat But it didnt help. The next thing I will try is when the Flow will be decreasing I will turn of the ac and will se if this will help.

I was searching for same problems on Google and this forum But I didnt find anything

Did anyone had similar problem?

 

[RUM4MO]

In a perfect world, you would buy a VW Group compliant scan tool, and use it to find out what is happening. Personally I own and use VCDS, using that should allow you to log what the many motorised flap valves are doing - and more.

Edit:- all these "flap motors" have positional feedback so you can log that.

Do you have auto HVAC or manual HVAC (heating cooling and air con).

Nothing wrong with your english.

 

[Walone]

You may need to 'reset' the heater flaps, the is a procedure for doing it by pressing certain buttons, but I'm not sure how.

 

[RUM4MO]

Yes, but only if it has auto HVAC.

 

[Seat0510]

Thanks for reply.
It was plugged to vcsd, but everything looked normal.. No strange or wrong errors. It was plugged when the problem occured and all flaps was working properly.

I think that I have auto hvac, when problem occured I reset the hvac flaps by pressing ac and torso vent direction. It was reseted but it didnt fixed the problem.

My mechanic did call some colleges to inquire some information, but none of them heard of this problem. They all said that if the blower is working normally, and it is. It is funny how the blower is working on Max But there is no air from all the vents.
Am I wrong if I say this, if one flap is closed other opens, so there is always one open to blow air, or is there a chance that there is a flap that closes all air Flow? I mean it would be strange that there would be this possibility, what would be purpouae of that..

He said that maybe the evaporator is freezing..

 

[Walone]

Yes, but only if it has auto HVAC.

Yes, I did make that assumption.

 

[RUM4MO]

When I ordered up my first VW Group car, a VW Passat 4Motion in 2000, if there was an option, I ordered the auto HVAC version due to that system being able to self diagnose - then I bought VAG COM as VCDS was called back at the beginning in either late 2000 or early 2001, when I ordered up a VW Group car for my wife I did the same thing, both were personal imports from NL so the difference in cost between manual HVAC and auto HVAC was peanuts - when compared with what the robbing UK imports charge us.

 

[Compo1]

Thanks for reply.
It was plugged to vcsd, but everything looked normal.. No strange or wrong errors. It was plugged when the problem occured and all flaps was working properly.

I think that I have auto hvac, when problem occured I reset the hvac flaps by pressing ac and torso vent direction. It was reseted but it didnt fixed the problem.

My mechanic did call some colleges to inquire some information, but none of them heard of this problem. They all said that if the blower is working normally, and it is. It is funny how the blower is working on Max But there is no air from all the vents.
Am I wrong if I say this, if one flap is closed other opens, so there is always one open to blow air, or is there a chance that there is a flap that closes all air Flow? I mean it would be strange that there would be this possibility, what would be purpouae of that..

He said that maybe the evaporator is freezing..

The is a connection pipe short piece from the blower motor to the distribution pipework. Check this has not dislodged at either end

 

[Seat0510]

The is a connection pipe short piece from the blower motor to the distribution pipework. Check this has not dislodged at either end

If it would be dislodged the problem would be constant right?
Because it just happens, then after a while when the car is not running the problem fades away..
I forgot to mention, after a two hour drive the problem occured, then I stopped on slight upright incline, car was running in neutral (let's say 5 minutes) and the air came out of vents normally.

But still, will check your propostion!

 

[RUM4MO]

If the evaporator was getting frozen up, then no air could pass through it, so, to prove that this is not happening, just switch off the chiller and run the system without any chilling from the AC compressor - it is possible to run like this. If you do that, and the air circulates as you expect, then yes, your mechanic could be right about the evaporator freezing up.

There is protection in these systems to stop that happening, there is a temperature sensor in/close to the evaporator, so if it was freezing that temperature probe would log that and that should (maybe) disable the AC compressor from providing a lot of cooling. If the fridge gas load is low, that could also cause freezing within the evaporator.

 

[Seat0510]

Yup, this is the next thing I will try. Tomorrow will all be known, because I have a 2 hour drive home

Will post the result.

 

[cuthound]

You may need to 'reset' the heater flaps, the is a procedure for doing it by pressing certain buttons, but I'm not sure how.

 

[Seat0510]

@cuthound
I've done that, but that never helped.

So the update is, apparently evaporator is freezing.. As soon as I notice waeker air Flow I turned off the AC and after a while (less than a minute) the Flow was getting stronger

So we figured what is the problem but not what is causing it..
Any idea?

 

[RUM4MO]

Might just be the gas charge is low, I'd start getting the running performance of the chiller checked by someone that knows how to use a fridge manifold. After that I'd check what the system thinks the evaporator temperature is, I thought that if the sensor in the evaporator is still working okay, and the temperature is too low, then the AC control system should be reporting a fault condition and reduce the duty cycle of the chiller to protect the system - or disable the chiller.

 

[RUM4MO]

Just another thought which I should have mentioned in my earlier postings, there should be a drain for the chiller section, so that any moisture gathering in there and ends up getting frozen, can drain out when the system is not being used.

Has that been checked yet, I don't know where the outlet for that drain would be on your car, but, if you park it in warm weather after using the chiller, then some water should end up on the ground underneath the car, if the drain is working.

 

[Seat0510]

My mechanic is getting into the problem, at least he know where to look at.

About the drain.. I think its not a problem, because when I had a problem with air flow and shutdown car, there was a huge puddle under. And always after normale usage there was some water underneath. So I think that this si not a problem, but Thanks for idea
I had a problem with roof drainage couple of years ago, I had so much water in spare wheel space. I had to take all the rear seat and to get all the water out at official service the "forgot" to clean drain pipes..

 

[cuthound]

Many years ago I used to maintain air conditioning plant in large commercial buildings. Three possible causes of the evaporator freezing could be lack of air flow (blocked pollen filter?), low refrigerant gas level pr possibly the condenser is dirty.