I’m working through the AC system components in the car sorting out a few things that have never worked.
So far;
I’ve got the demist and center vent flaps back working properly, cause was a failed vacuum solenoid on the demist flap
I’ve got the passenger side blower out to repair the electronic control board. The transistor/diode control had failed resulting in high speed all the time the ignition was switched on. This is because the transistor can fail earthing the ignition switched power supply.
The one I haven’t worked out are the operation of the re-circulation/fresh air flaps on the blowers. These are operated by one of the vacuum solenoids under the AC unit and vacuum servos mounted on the side of each blower. When the vacuum solenoid is given 12v it applies vacuum to the vacuum servos and moves the flaps to close the fresh air inlet and open the recirc to each blower. My vacuum solenoid is working OK but I cant move the controls to any setting that make the flaps move to the recirc position.
Can anybody tell me under what circumstances or settings does the Delanaire unit apply 12v to this solenoid and move the recirc flaps open and the fresh flaps closed?
Or any ideas why its not happening?
So I’ll answer my own question!
I’ve found that the system goes to recirc only when the ignition is on and the fan switch is in the off position.
My system wasn’t doing this because the vacuum servo on the drivers side had failed and couldn’t hold vacuum.
Other problems I’ve discovered and sorted out are;
Center/demist flaps not moving due to one failed vacuum solenoid under the main Delanaire unit on the right hand side, replaced solenoid with second hand unit
Left hand blower not working at all, found that the main fuse had been removed, when I put it back in it the blower ran on full speed whenever the ignition was on. Replaced the electronic circuit board and all its components (Darlington transistor etc) according the instructions found in the book and now working as it should.
Some time ago I found that the heater valve was jammed open and replaced this.
I have ordered a new vacuum servo for the drivers/right hand blower from SNG barrat and plugged the vacuum line running to it in the meantime. So removing this blower lies ahead of me and if its as much fun as getting the left hand one out I’ll book an appointment with the physio now!
I still have no cooling as the condenser failed some time ago but that’s not a priority for Irish summer weather!
Yes indeed, the recirculation flaps close when the fans are off, but that is to stop fresh air from entering the cabin when the system is off.
More important though, and at least on the Delanair II, the system goes into recirculation mode also when full cooling is demanded.
Others might chime in, but I don’t see any reason why the Delanair III would behave differently.
The Delanair 3 on my car works as described by Aristides. I added a manual switch to PREVENT the solenoid from closing the recirc. flaps, so I can have outside air enter the car at speed without the fans running.
And one for the A/C compressor…
How to’s in Kirkby’s book.
For switches I’ve used the two interior light switches on the centre console and made a fan and a/c symbol.
Pics in the photo albums.
Best
Aristides
Me too on the A/C compressor switch. It made no sense that the compressor has to run under all circumstances. Just a couple of days ago I added a vacuum operated switch to shut down compressor at full throttle!