air con, what tempreture

[Odd Job]

Where did you have it re-gased?
Some places use " re-cycled" gas as when they do a re-gas the system gets evacuated first, pressure tested then if no serious leaks detected, re-gassed.

Most modern systems are automated. Connect the car up and leave to their "thing" for 30 - 45 mins.

So, in short. Any "old" gas in the system gets removed first before being recharged.
Your "new" gas is actually partially re-used gas which will be contaminated with atmospheric air, water, and oil etc.
So your air-con system will never be up to its original capacity even if its fully functional.

Hard to find a place these days that use " new " gas in a system.

[SD1too]

Originally Posted by Odd Job

Some places use " re-cycled" gas ...
Your "new" gas is actually partially re-used gas which will be contaminated with atmospheric air, water, and oil etc.

How did you discover this Richard?

Simon

[BigRuss]

Originally Posted by macafee2

tested yesterday after new condenser radiator fitted and re-gassed and it was 7 or 8 degrees..
The outside temperature sensor is not fitted to dash shows -30. not sure f that makes a difference

macafee2

With a fully charged system 7-8 degrees C at the vents is typical on most cars

Note a diesel with the temperature sensor disconnected the cooling fan will not operate when the ignition is switched on as you would expect.

Russ

[SCP440]

Originally Posted by SD1too

How did you discover this Richard?

Simon

This has been common practice for a while, have you seen the price of R134A now? Not that long ago a 13kg bottle was about £100 now it costs about £300 and we are told how bad it is for the environment? If an engineer can use ''old'' gas of course he will. I have been told it is going to get more expensive as the new gas is being phased in.

[first-things-first]

Originally Posted by SD1too

I've wondered that ever since I noticed mine running when there was snow on the ground.

Simon

I thought there should be a frost sensor to tell if the evaporator is iced up. That's when it's likely to cause damage.

I also think you should run the system at LO as had been said and with recirculation on to get to the lowest temperature. As had been said measure at the face level vents.

[SD1too]

Originally Posted by BigRuss

Note a diesel with the temperature sensor disconnected the cooling fan will not operate.

That's interesting Russ. Not wishing to fall into the trap of making assumptions, can I just check with you a couple of details?

• You're talking about the ambient temperature sensor in the front bumper, yes?
• Is this true only in respect of the air conditioning? The fan will operate normally in the event of high coolant temperature, yes?

Simon

[SD1too]

Originally Posted by SCP440

This has been common practice for a while ... If an engineer can use ''old'' gas of course he will.

I just wondered how you and Richard know that this is true, i.e. you have proof, as opposed to speculation or hearsay. 'Fast-fit' centres and garages don't let customers remain in the workshop to watch the process do they, so how would you know what's going on? That's why I always use an independent self-employed mobile specialist who is happy to explain to me what he is doing and crucially, I can see him change cylinders between evacuation and charging.

Originally Posted by first-things-first

I thought there should be a frost sensor to tell if the evaporator is iced up.

There is Andrew, but I wasn't talking about the evaporator. I was pointing out that the air conditioning can run in 'auto' mode even when the ambient temperature is below the target temperature set inside the vehicle. Our system doesn't work on what we might consider to be 'logic'.

Simon

[BigRuss]

Originally Posted by SD1too

That's interesting Russ. Not wishing to fall into the trap of making assumptions, can I just check with you a couple of details?

• You're talking about the ambient temperature sensor in the front bumper, yes?
• Is this true only in respect of the air conditioning? The fan will operate normally in the event of high coolant temperature, yes?

Simon

Yes it's the ambient air temperature sensor, that's why if you've got the bumper removed to repair or replace the fan and you want to check for correct operation, you need to plug in the wiring to the bumper
The default temperature with the sensor disconnected is -30C so the ac system thinks it doesn't require the fan as it tinks that at that temperature ac would not be required

To be honest I've never bothered to leave it unplugged and leave the engine running for that long as it takes an awful long time on a diesel with it idling to get the cooling fan to kick in because they don't generate a lot of heat unlike the petrol models. In the time it would take to do that the car would be completely re-assembled and happily on it's way.

I would expect though that the cooling fan would operate when it got up to the required temperature as it's controlled by the engine cooling temperature sensor.

Russ

[SCP440]

Originally Posted by SD1too

I just wondered how you and Richard know that this is true, i.e. you have proof, as opposed to speculation or hearsay.

It is how it works, the automatic machines drain the system and put all the reclaimed gas in a cylinder inside the machine, the machine them performs some pressure tests and pulls a vacuum. Once the vacuum is pulled and it holds the machine then fills the system with the required amount of refrigerant. There is only one cylinder in most of these machines so the chances are if you system was partially full you are paying for some of your old gas.

Some of the scrap dealers that actually do reclaim the gas out of scrap cars are doing a great trade now the price of virgin gas is so high.

In truth most A/C systems if they are working are in good order, the only way contaminants can get in there is of some work has been done on the system and a proper vacuum was not pulled before the gas was put in. Most of these systems have a filter.

[chris75]

Originally Posted by SCP440

the chances are if you system was partially full you are paying for some of your old gas.

My local place explained to me that their charges are made up of a base rate of £34 for the process plus so much a gram for the "extra" refrigerant which has to be added to that which was recovered from your system . So , the old refrigerant is returned to your system but you are not charged for it .