i finally got round to getting my aircon serviced, it wasnt clear from all the service sheets since 2009 if it had ever been done...it felt pretty cool at low (18*) but since the service also includes adding lubrication for the unit and taking out any nasties in the air ducts i thought it was really time to address the issue

the garage told me on inspection there wasnt much refrigerant and told me the type of flexible tubing used is porous and over the years looses the refrigerant due to migration through the walls of the tubes, which sort of co incides with the time i think the unit hadnt been services

after completion the difference was phenomenal...firstly the car smelled like a tropical island...after a day or so the fragrance got less

the performance was chilling to say the least...on low (80*) it used to be as cool as 20* but now at low...you can feel the refrigerant effect

the advice to me was to run it at least 10 minutes a day...and all the year round as aircon was to heat as well as to cool...

it cost £45 for the service and £15 for the "smell"

£72 including VAT

its a local independent garage....

"aircon was to heat as well to cool" - not really in these systems, in really high performance heating/chilling plant, the chilling is always available to cut in and trim back any excess in target temperature during ramping from one set point to the other, but in a car any temperature errors between set point and measured values will just be taken care of by moving the air blending flap to either pass more or less outside ambient air to trim the error back. I'd be very surprised if chilling is ever used to trim back temperatures when you are actually aiming to heat the car interior up. Also the comment about needing to run the chiller frequently to keep it in good order is really old hat with systems with variable displacement compressors that are continuously connected to the drive pulley.

30 minutes ago, rum4mo said:

"aircon was to heat as well to cool" - not really in these systems, in really high performance heating/chilling plant, the chilling is always available to cut in and trim back any excess in target temperature during ramping from one set point to the other, but in a car any temperature errors between set point and measured values will just be taken care of by moving the air blending flap to either pass more or less outside ambient air to trim the error back. I'd be very surprised if chilling is ever used to trim back temperatures when you are actually aiming to heat the car interior up. Also the comment about needing to run the chiller frequently to keep it in good order is really old hat with systems with variable displacement compressors that are continuously connected to the drive pulley.

i dont know about the compressors design etc...but did wonder how a chiller can heat a car??

i assumed it was simply the hot water in the heater element gets blown into the car...which i guess is controlled by an inlet valve??

no matter my car gets cold when i want it to and last winter it really heated i up with the dial on 24 and the fan on max

dont think the compressor..in fridge terms would be needed then..!!

what is the drill for keeping the unit in good working order when not needing to be used...there must be times you dont need hot or cold...maybe the odd blaster setting to clear the windscreen..

one other slightly side issue...does air con give you a dry-ish throat or headaches?????

i might have laryngitis but after an hours driving with the chill setting...20 and the fan on around 1/3 setting...

that is AUTO on my model

cheers

geof

When used for heating up the car, there is a flap on the air box which allows all or some of the incoming air or recirculated air to pass through the heater matrix or bypass it, this system is a lot cheaper and reliable (as long as the flap motors stay working) than a motorised water control valve on the heater matrix.

 

When the chiller is running, as the evaporator is also in the air box, it will strip a lot of the moisture out of the incoming air so dry the cabin and assist demisting the windows etc.

 

I think that 23C was the normal suggested set point for cabin temperature, though I might be wrong, I think that leaving the temperature set at that value stops the cabin fan running unnecessarily, typically I will adjust the demanded temperature to reduce the cabin fan speed if the air in the cabin meets with my approval! (what the person in the other seat thinks is not relevant, maybe!).

 

The only "smart" thing that I try to remember to do is to disable the chiller and demand "Lo" about 5 miles from home, so that the air box and so evaporator surfaces are at ambient temperature and dried off - to reduce bugs living/growing in the air box.  Mine you, outside temperatures need to be quite high before I bother to run the A/C - same when I hire a car in warmer countries, just a habit!

 

No harm in running the chiller to cool/freeze the car now and again if only to make sure that it is still available and working in case you need it.

What is the caveat about not letting the bearing dry up on the compressor?

 

your remark about flaps reminds me of the discussion on synchronisation 

it seems that on some journeys without any air conditioning/ heating on I have felt what seems like a bit of heat on my clutch ankle...but can’t detect it on my downstretched left hand 

is there something I should do to check if any flaps are Ok 

 

cheers

geof

 

Edited 15 July, 20187 yr by mrcrow

21 is meant to be a comfortable working environment. If you have auto set, it will part chill, part warm, keeping the system healthy UNLESS you press the econ button. It will then turn the a/c to (very nearly) off. Keep as cool as you feel you need to and use the system once or twice a month minimum to help prevent the seals drying up. That is the usual advise, even if you don't like the chill! (Hence chill and heat simultaneously).

 

You have climate controlled a/c (Climatronic)  As opposed to basic a/c. (Climatic).  This system tends to like to set temperature at 22 unless you change it yourself. 

 

Try it. Turn the system to econ and reduce the temp to low. You will now need to set vent direction. Then, press auto and it will go back up to 22 and direct air where it senses it needs it. 

13 hours ago, mrcrow said:

What is the caveat about not letting the bearing dry up on the compressor?

 

your remark about flaps reminds me of the discussion on synchronisation 

it seems that on some journeys without any air conditioning/ heating on I have felt what seems like a bit of heat on my clutch ankle...but can’t detect it on my downstretched left hand 

is there something I should do to check if any flaps are Ok 

 

cheers

geof

 

With these systems having a fixed compressor drive, ie no clutch on the pulley, there is no issue with the bearings, or more correctly the seals drying out as a small quantity of oil will always be carried round the system with the small quantity of gas that get circulated as the compressor when operating under no cooling demand, is still driving gas round the system as its minimum possible displacement is still some displacement.

5 hours ago, rum4mo said:

With these systems having a fixed compressor drive, ie no clutch on the pulley, there is no issue with the bearings, or more correctly the seals drying out as a small quantity of oil will always be carried round the system with the small quantity of gas that get circulated as the compressor when operating under no cooling demand, is still driving gas round the system as its minimum possible displacement is still some displacement.

 

that makes sense now as i thought the compressor was on only when you pressed the auto and set the temperature lower than the interior temperature...which leads me to asking if an internal temperature gauge would be handy...i have often wondered what the interior temperature was...even though i can see the outside temp on the panel in front of the steering wheel...this could actually help to see if i really need to lower the interior temperature at all...i do it since the car is very hot starting off having stood in the sun for a few hours etc.

cheers

geof

 

18 hours ago, mrgf said:

21 is meant to be a comfortable working environment. If you have auto set, it will part chill, part warm, keeping the system healthy UNLESS you press the econ button. It will then turn the a/c to (very nearly) off. Keep as cool as you feel you need to and use the system once or twice a month minimum to help prevent the seals drying up. That is the usual advise, even if you don't like the chill! (Hence chill and heat simultaneously).

 

You have climate controlled a/c (Climatronic)  As opposed to basic a/c. (Climatic).  This system tends to like to set temperature at 22 unless you change it yourself. 

 

Try it. Turn the system to econ and reduce the temp to low. You will now need to set vent direction. Then, press auto and it will go back up to 22 and direct air where it senses it needs it. 

thanks

brilliant!!

is econ meant to save on fuel?

i will try that little check you mention...and probably raise the auto temp to 22 just to see how that goes...i have been using 19 sometimes..

cheers

geof

 

Econ will almost stop the cooling of the a/c system, thus save a little on fuel costs too. It is estimated that a/c saps about 10% of fuel usage so driving at lower speeds, it may be better to leave it off and open the windows but at higher ones (40+) It will be better to close the windows and use the a/c as the wind-drag will outweigh the saving. I set 18 or 19 when driving with students, to keep them cool and stop them getting flustered. 22 seems to be the cars go-to setting and 21 is supposedly a good working environment temp in offices etc. 

45 minutes ago, mrgf said:

Econ will almost stop the cooling of the a/c system, thus save a little on fuel costs too. It is estimated that a/c saps about 10% of fuel usage so driving at lower speeds, it may be better to leave it off and open the windows but at higher ones (40+) It will be better to close the windows and use the a/c as the wind-drag will outweigh the saving. I set 18 or 19 when driving with students, to keep them cool and stop them getting flustered. 22 seems to be the cars go-to setting and 21 is supposedly a good working environment temp in offices etc. 

thanks

all good info for me to work with...

my wife likes windows open which i object to...but now i will let her know she is saving fuel and turn my hearing aids off...

cheers

geof

Always the best approach, with the Mrs sitting next to you anyway!

Mrcrow, when you had the air con re-gassed, did they tell you how much you had removed and how much they put in? (A little printout, like a till receipt).

 

Just wondered what the norm is for these cars... Also, as I just had mine done today, the gut suggested when its very hot, to press the resirc button for a few mins when first starting the car as he says it chills the air you are already chilling, giving the compressor an easier life! I hope I made sense, there! Rather then chill a continual flow of new air, you will cool and re-cool the same air for a few mins. This will cool the interior quicker and give the system an easier time. I usually open the windows for a few mins, to let the heat escape so I am gonna try his suggestion for a while and see how it goes. I am also interested in seeing if my fuel economy increases now as there is more gas in the system and it should chill more efficiently. It had been struggling to chill when stationary or on slow driving but was fine on faster driving. 

Edited 20 July, 20187 yr by mrgf

What the garage said about the refrigerant diffusing though the rubber lines over time is true; it's a process normally called osmosis (at least in chemistry; automotive engineers may have their own name for it).

20 hours ago, mrgf said:

Just wondered what the norm is for these cars... Also, as I just had mine done today, the gut suggested when its very hot, to press the resirc button for a few mins when first starting the car as he says it chills the air you are already chilling, giving the compressor an easier life! I hope I made sense, there! Rather then chill a continual flow of new air, you will cool and re-cool the same air for a few mins. This will cool the interior quicker and give the system an easier time. I usually open the windows for a few mins, to let the heat escape so I am gonna try his suggestion for a while and see how it goes. I am also interested in seeing if my fuel economy increases now as there is more gas in the system and it should chill more efficiently. It had been struggling to chill when stationary or on slow driving but was fine on faster driving. 

Mrcrow, when you had the air con re-gassed, did they tell you how much you had removed and how much they put in? (A little printout, like a till receipt).

good call that ...the recirculation

i have been doing some deep studying the manual on the climatronic and didnt know the recirc could work with chilled input as well as what i thought the reason for it was to heat up the car quicker in the winter..!!

you have a good idea there and i will try it...

i have been keeping the windows open a bit when i finally get onto the open road...and then putting the auto on...

mileage is something i have been quite observant now with the diesel additives in the tank..got a 64 on a recent drive and using a bit of turbo in overtaking...not really interested in acceleration all the time...like to build up speed

i have also observed slow driving/stationary chill inefficiency and think its best avoided...i think the manual makes some suggestions about this...now that i have read it properly!!

when about 5 miles from home...did you suggest this...turn the auto up to 30 degrees to dry out the tubes and avoid any condensation..whatever...lying there

your last point about re-gassing...

i checked the receipt but there isnt any sign of quantities but as i was waiting in the office the boss came in to say everything was going and was going to re-gas...saying when he emptied the system it only had about 150 grams in the system instead of the recommended 450...he filled it to 350...he said he thought what was coming through was really not chilling...and thought it was just the cold air speeded up by the fan

it does really chill now

i am using the temperature on chill at 21-22 and can feel chill coming through...

the outside temperature given on the instrument panel could be lower slightly but i reckon the car interior is much higher due to the sun coming through glass...

have you an internal temperature gauge...i might get a small one?

cheers

geof

 

20 hours ago, KenONeill said:

What the garage said about the refrigerant diffusing though the rubber lines over time is true; it's a process normally called osmosis (at least in chemistry; automotive engineers may have their own name for it).

thanks

i remember osmosis...engineers use the term as well...its in water treatment plants i think..probably the term molecular migration might be used

being a structural engineer i dont think i have come across it except to try to understand it....possibly in concrete reservoirs/

glad you contributed that though...one doesnt think about their car in that way..

some folks confuse it with capillary action as well

cheers

geof

Edited 21 July, 20187 yr by mrcrow

Blatant off topic comment:- in the last house my mate bought, previously owned by a RR engineer, aero engines division I guess, there was a low voltage supply connected to the stone work - some internet searching revealed that it was designed to stop or slow down dampness in the lime mortar! Ie reverse osmosis I think the term is.

52 minutes ago, rum4mo said:

Blatant off topic comment:- in the last house my mate bought, previously owned by a RR engineer, aero engines division I guess, there was a low voltage supply connected to the stone work - some internet searching revealed that it was designed to stop or slow down dampness in the lime mortar! Ie reverse osmosis I think the term is.

for us chaps..right on topic 

Couldn’t comment on the term, but if it worked...ace!

steel is protected from corrosion by using low voltage dc current 

 

ps during my sojourns on the web regarding the Skoda climatronic system on my model and year there are two small vents one at each end of the selection panel and acts as cabin sensors to control temp feedback....as recommended I gave them a gentle vacuum to remove particles of dust from the louvres 

cheers

geof

Ps.  Been reading the manual again...!..

 

Edited 21 July, 20187 yr by mrcrow

Gunsons used to try to flog a corrosion resisting system like that for cars, lots of buried steel pipes use zinc lumps to protect them, sacrificial anodes, the zinc lumps dissolve and save the metal on the pipes, same thing with steel parts on boats.

I think that typically while there are 2 sites for temperature sensing, only 1 is used on RHD cars and the other 1 is used on LHD cars, there will be a very small fan in them to drag air over a sensor, keeping a vac cleaner on them for too long might just annoy these fan's small bearings as you will be "over revving" them.

The comment about drying out/off the evaporator in car A/C systems sounds a bit like my banging on about this - it does make sense though for us in UK, probably not an issue in some climates though!

4 hours ago, rum4mo said:

Gunsons used to try to flog a corrosion resisting system like that for cars, lots of buried steel pipes use zinc lumps to protect them, sacrificial anodes, the zinc lumps dissolve and save the metal on the pipes, same thing with steel parts on boats.

I think that typically while there are 2 sites for temperature sensing, only 1 is used on RHD cars and the other 1 is used on LHD cars, there will be a very small fan in them to drag air over a sensor, keeping a vac cleaner on them for too long might just annoy these fan's small bearings as you will be "over revving" them.

The comment about drying out/off the evaporator in car A/C systems sounds a bit like my banging on about this - it does make sense though for us in UK, probably not an issue in some climates though!

Yes..one of the jobs I got to do as an apprentice in the ship repair dry docks was to fit new  “spelter plates” where the previous ones were decayed 

there were a lot on the hull and on tankers in the tanks for when they were ballasted with seawater.

cheers

geof

 

 

 

 

@rum4mo @mrcrow - The zinc stuff is called "sacrificial corrosion" at a process level.

41 minutes ago, KenONeill said:

@rum4mo @mrcrow - The zinc stuff is called "sacrificial corrosion" at a process level.

Thanks...we did a bit of this at college in science 

are you in petro-chem?

cheers

geof

You can buy cold galvanising (zinc) spray can from many places inc toolstation, easy application.

Great stuff for fabia drums.

 

A knowledge and understanding of galvanic series is useful to avoid problems.

 

http://structx.com/Material_Properties_001.html

 

 

 

@mrcrow - No, but I did chemistry to part-way through university, and this "useful stuff" has stuck with me.

4 hours ago, xman said:

You can buy cold galvanising (zinc) spray can from many places inc toolstation, easy application.

Great stuff for fabia drums.

 

A knowledge and understanding of galvanic series is useful to avoid problems.

 

http://structx.com/Material_Properties_001.html

thanks

thats a great chart and that mild steel is pretty close to the zinc with navy brass a bit further away

i cant remember what the propellors were made of exaclty...phosphor bronze?...but they suffered from cavitation as well

i see the site mentions structures

did you work in steel design or marine engineering...

i did some years designing steel structures which some of which needed to be galvanised instead of painting

it caused a lot of expense and with tubular structures holes had to be left to allow the tube to breath during the process and draining off zinc after dipping since zinc went inside so a lot of zinc was used to no real advantage...£££

it had to be done at a specialist works and in our case their baths could only take certain sizes of structure...

that was in Charleston in cornwall

the timing had to be co-ordinated so that the load could be delivered to site after galvanising

the drums!!! never thought of that...i thought bright red was the boy racer's favourite colour...is that a second coating?

cheers

geof

 

4 hours ago, xman said: