Zafira aircon fan

I have just regassed our 2000 zafs aircon with one of those bottles you get
from halfords. It comes with a pressure guage as well to help not
overfilling, and the results have been mixed. it must have been too low
before so the clutch wouldnt engage on the compressor. well it does now ok,
but the
temperatures achieved have been a bit disappointing, beeing slightly cool at
best, when driving at @ 50 mph. Does anyone know if the fan in front of the
condensor (the part in front of the radiator) should come on as soon as you
turn on the aircon? I am wondering if there might be a lack of cooling
somewhere.

Mike

 

The "topup" cans are a bit "hit and miss", you might not put enough in and
just as easily you could overcharge. If the clutch was not clicking in
before, you basically had no gas in it, and you will need 600g approx (you
might find a sticker in the engine bay somewhere) to fill it. What was the
weight of the gas in the bottle?

Not sure about the Zafs, but some cars run the fan at a slow speed whenever
the ac is on, and increase the fan speed if the pressure / temp rises, some
only run the fans at all if things get hot.

If it's not running, could be the fan's broken, or could indicate there's
not enough gas for the system to reach normal running pressures. But the fan
won't make much differenence if you're doing mouch over 30, so if it's still
not cooling all that well, it's probably lack of gas.

Of course, you have a leak somewhere, without having the gear you won't know
if it's a big or small one.



www.poolecool.co.uk

 

Another related enquiry:



I am not 100% sure of the details of your car, but generally:

- All modern cars use r134a, which will have a pressure of 40-60 psi if the
car is cold, if there is more than 20% of the required gas volume in the
system - 20-100 % won't make any difference to the ambient pressure as it
just increases the amount of condensed refrigerant.

- Pressure switches are normally on the pipework, not on the compressor. If
they are on the compressor, it is normally easy to see which connections go
to the clutch (behind the pulley) and which go to the switch (normally at
the pipework end of the compressor)

- If you have 12v at the clutch but it is not clicking in, try measuring the
resistance of the clutch coil, should be no higher than a few hundred ohms.
If it is open circuit, it's broken.

- If not, check that the clutch supply is solid, perhaps by wiring a 21W
brake light to the supply side and checking it lights well when you turn the
ac on.

- If you have a good supply to the actual clutch, and the clutch coil is not
open circuit, but does not click in, also it is broken, but in this case it
might just be jammed, you could try squirting it with wd40 etc. (but wash
out the wd40 if it starts working).


www.poolecool.co.uk

 

But if the gas level/pressure is low, will this give a reduced cooling
effect, assuming theres enough in to trip the level switch so the compressor
clutch engages?

And is it best to fill when warm or cold?

Mike

 

Yes, by ambient I meant the pressures when the system is not running.

Doesn't matter.

 

Well an update on this is that I've had a chance to look again and both fans
are working. I just sat with it idling and waited, and they both kicked in,
but not at the same time. I tried gassing it some more but cant get more
than @ 25psi with the can (theres a pressure guage included). result is that
the condensor (the thing in front of the radiator ) now gets hot, just
before the front fan kicks in. too hot to touch in fact, but I still cant
get any cold air in the car. its cooler if I just turn the aircon off. The
controlls are set to : aircon on, recirculate on, temp all way down to
coolest. Any ideas anyone? or am I going to have to take it somewhere to get
the pressure up some more? because I just cant seem to get any more gas in,
but the can appears to be half full now. I've been putting it in when its
running (as instructed on the can) into the low pressure side (it will not
fit the HP side).

Mike

 

As I hinted at earlier, it is more likely to be by luck than anything else
if you get the correct charge with these topup cans. But I'll try to make
some helpful comments:

- It is unusual not to get any cooling at all if the condensor is getting
very hot - can you quantify what temps you are getting out of the vents
(with the ac on and off)?

- How much gas (in grams) do you think you've put in?

- You might get something like this if the system was previously
contaminated with air, the refrigerant is much less efficient if mixed with
air (and can cause other problems such as chemical breakdown), or if the
system now has too much gas in it, or if there are other faults (expansion
valve, etc) but it is difficult to have an educated guess at what it might
be without knowing also the high side pressure.

- Can you find any part of the system which is cold (the low pressure pipes
at the compressor or evaporator, for example)?



www.poolecool.co.uk

 

I dont have a thermometer that can do this, but I can say that its warmer
with the aircon on than off.

Difficult to say. I have used about half of a 562ml can. It has a pressure
guage with it. I'm not sure if its making a correct connection onto the LP
side. I can press the button on the can and send the pressure up to about
65-70 psi, but I think that all thats happening is that its pressurising the
tube. If I press the top of the connector onto the LP connection the
pressure reading drops when it is running to @ 25 psi, and I cannot get any
better than that. Its worth pointing out that before I started all this the
compressor clutch did not engage at all, but when I got some gas in, it
fired up straight away.

Pass. I have no way of connecting to the HP side. (thats the one thats part
of the condenser, isnt it?)

I'll get back to you on that when i can try next. If I understand it
correct, the LP pipe is the thick one from the compressor that disappears
inside the car, and has a large(ish) can type device in line that has the LP
connector filling point on it.

Mike

 

Forgot to say, this is what I've been using


http://tinyurl.com/pk6k6


Mike

 

i should hope it does not fit the high pressure side
it will take you hand off!

there could be 1001 things wrong.
go to a specialist, its much safer.

mike

 

Well, that looks like 19 oz, which would be about 540 gms.

If you've put one of these fully in from the point when the clutch did not
engage, you wouldn't be too far wrong, assuming no air in the system before.
But reading through the posts, you may have put 1 and a half of these in,
which would almost certainly be too much.

Almost certainly, time to learn how to do this professionally, or get a
professional to do it for you.

www.poolecool.co.uk

 

ummmm
you do have the blower switched to 3 don't you ?

dB

 

Well, that looks like 19 oz, which would be about 540 gms.

Actually, all I've managed to get in the system is about half, maybe
slightly more, of that one can. thats it. and I cant seem to get any more in
at all.

Do professionals pump it in from those larger cans? or does it still go in
under its own pressure?

Mike

 

yep, that or 4. also got the vents to blow from the face ones. I cant see
the vents making a difference, i.e. only blowing cold onto the feet?

Mike

 

So you might have about 300 gms in, which assuming the clutch did not click
in when you started, is probably all there is in the system, which won't be
enough.

I generally pump the gas in, but you should be able to get the system to
suck it in by running the engine and air con while you have the can
connected - have you been doing this, or have you have the system switched
off while trying to get the gas in?

www.poolecool.co.uk

 

I was wondering about this.

I've been trying while its running. Instructions on the can say so, and to
shake the can while you do so. (and also beforehand as well) presumably
this is to mix up the gas and oil thats supposed to be in the can. however
its bloody near impossible to shake while its running as theres only about 6
inches of pipe
and its right next to the alternator. There is no room to hold the can
vertically and I am wondering if there is a tube inside the can that draws
from the bottom. if so then because I have to have the can in a near
horizontal position perhaps it is drawing vapour from the top half of the
can rather than fluid from the bottom (if you can picture this in your
mind). I'm kind of guessing the can is self pressureising, and doesnt have
any kind of propellant gas other than itself.

Mike

BTW, cant get at the car till this evening as the wife is out in it.

 

If the system is running normally, even if the gas pressure is low, it
should suck out condensed gas from a can. Maybe you have some other fault.

www.poolecool.co.uk