Post Number: 47
|Posted on Thursday, 04 May, 2017 - 12:26 pm: |
The AC on my 78 Shadow was slightly warmer than it should be recently. I was thinking I was low on freon, but discovered the servo was not completely closing the upper dash vents. I disconnected the rod going to the vents (from the servo) by manually pushing the rod upward. I immediately got ice cold AC. I noticed on the side of the servo "+ and - ". Is the rod adjustable on the servo with the +/-?
Post Number: 1805
|Posted on Thursday, 04 May, 2017 - 06:04 pm: |
Hi Richard, yes . . . sort of. It adjusts the 'CENTRE' temperature.
So it adjust the bias to warmer or colder.
In the UK when the weather is cold, it is often normal not to get freezing air from the vents. RR think that there is a 'normal' range of what you should want - White centre. Red and blue adjusts this centre.
It should pretty much work itself out and if you jump in the car with it on white it will give you heat in the winter, ambient in the spring or Autumns and freezing in the summer. If you get what I mean!
So no freezing air available in the winter or No boiling air in the summer is quite normal . . . but confuses many owners.
In fact, RR were so confident that the cabin temperature would remain static that they added an outside temperature gauge to prevent owners getting Thermal Shock. In case you drive from -10c in the Alps to +30c at the beach in Monaco!
Post Number: 48
|Posted on Thursday, 04 May, 2017 - 09:43 pm: |
Thanks! Understand what RR was thinking! Interesting!
Therefore, are you saying the servo adjustment does adjust the rod to close/open the top vents to make the heat/cooling adjustment?
I just want to be absolutely sure before I do anything to tamper with the factory system!
Robert Noel Reddington
Post Number: 1410
|Posted on Friday, 05 May, 2017 - 06:16 am: |
I would suggest that the adjustment is for setting up when new and setting up if the system is removed and refitted.
take a photo of the position of the adjustors before experimenting.
Post Number: 1806
|Posted on Friday, 05 May, 2017 - 08:24 am: |
There is a daisy chain of sensors.
So hot outside the car , hot inside the car, hot sun on the dash will give very cold air.
But. Hot outside cold inside no sun on the dashboard will give not so cold air.
But it;s like a hot cold see-saw. -20 outside, ok inside will bring on warmer air than you might want.
The adjustment resistor could be imagined as the pivot point of the see-saw. Move it and you need less heat at the sensors to make hot air come out, move it the other way and you need more heat at the sensors to get hot air to come out and visa versa.
Of course you should measure the sensor chain to make sure that the resistance is correct.
It's very fuzzy and not perfect though.
Just be aware that you shouldn't expect full air con on a cold day with a cold interior, or full heat on a hot day with a hot interior.
Does that make any sense? lol.