Some more County info please...

So after about 10 minutes of trial and error, I think I have all the vac hoses correctly connected on the back of the control module. Push the button that looks like an open book :p vents open/close, windscreen goes to windscreen and circle is closed. The A/C switch is irrelevant for now.

The fresh/recirculate switch opens and closes the vents under the dash in the footwell, the slider moves the lever on the side of the heater/A/C box in the engine bay for air flow - I can hear the flap.

I now realise the vac servo in one of the pipes disappearing into the heater box is the heater tap itself. This does not seem to operate.

A check with a mirror shows a vac line connected to it (red I think).

-Can anyone tell me where that vac line goes to so I can follow it to ensure it's operational?
-Could the vac servo have failed? How would I check this?

I'm still not sure what the vacuum servo beneath the grille on the left guard is for, or is it a small reservoir? The fresh/recirculate one is in the bottom of the dash so it' not for that...

I know the one for the CDL is the sphere on the RH guard - I assume the same one provides vac for the Maxi Drive??
Phew!
Cheers
Mike

I'm still not sure what the vacuum servo beneath the grille on the left guard is for, or is it a small reservoir? The fresh/recirculate one is in the bottom of the dash so it' not for that...

From what I can remember the one on the left guard has to close when the one under the dash opens.

I don't think there is a heater tap, just a flap that redirects the air either over the heater core or bypass it.

Jim.

Hi Jim
There's def a vacuum servo in-line on one of the water pipes going into (or out of) the heater box ;)...

Ok cool, so the guard one opens and another closes the recirculate vent?
Cheers
Mike

Quote:

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Originally Posted by 2 rocks

...

I now realise the vac servo in one of the pipes disappearing into the heater box is the heater tap itself. This does not seem to operate.


....
I know the one for the CDL is the sphere on the RH guard - I assume the same one provides vac for the Maxi Drive??

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The OEM vac heater valve is a silly idea for the Australian climate. Every time you shut the engine down it opens, heating up the cab. Better to fit a manual valve that you can close permamently in summer.

MD lockers usually use a separate vacuum tank made from ~8" of exhaust pipe.

Quote:

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Originally Posted by 2 rocks

Hi Jim
There's def a vacuum servo in-line on one of the water pipes going into (or out of) the heater box ;)...

Ok cool, so the guard one opens and another closes the recirculate vent?
Cheers
Mike

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Yes you are right on both, as isuzurover has said I do remember that stupid heater tap.
Jim.

Mike,
Attached photo might help. I have long ago removed the cock.



Regards

Jim

Quote:

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Originally Posted by isuzurover

The OEM vac heater valve is a silly idea for the Australian climate. Every time you shut the engine down it opens, heating up the cab. Better to fit a manual valve that you can close permamently in summer.
MD lockers usually use a separate vacuum tank made from ~8" of exhaust pipe.

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Agreed! :) The whole system is silly...logic would suggest that a slide control for temperature would increase/decrease the flow of hot water through the matrix.

Hmm, re the MD, looking at my in-cab actuator and valve it is tapped off a t-piece that's also going to the CDL actuator, so I hope the spherical reservoir is sufficient for both...

Quote:

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Originally Posted by Carslil Jim

Mike,
Attached photo might help. I have long ago removed the cock
Regards
Jim

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Thanks for the pic, Jim. OMG! it looks like there's two of them in that photo :eek:. I'll have to pull the air filter off and have a look...but by the sound of it I might have to replace the "tap" as you've done, but see if I can think up something to allow in-car operation of it.

Seeing as the lever only opens and closes an air flap, could that not be attached to manual tap? After all, airflow can be controlled via the "o" switch on the panel, or circumvented by choosing recirculate, negating the need to operate the flap in the heater box. The cable terminates in the right place after all...
Cheers
Mike

G'day Mike,
In the picture that Jim posted you can just see a whitish/yellow rectangular block mounted to the side of the heater box (its just above the heater tap in the pic). From memory, this is actually the switch that controls when the heater valve is closed off. The lever that operates the flap in the heater box needs to be adjusted so that when on the coldest setting on the dash the lever controlling the flap presses against a button on this switch, which then closes off the hot water flow - well that was the case with mine anyway. I agree it seems like a dumb idea as moving the lever just a little from the coldest setting then opens up the whole hot water system to circulate through the heater box. However, once adjusted correctly it does seem to work ok.
Adam.

I worked on a air conditioning / heater system recently in a County and it was a vacuum operated system.

The pipes and valves were full of fine dust, after blowing everything out with compressed air and changing a few perished parts, it was back operating as good as new.
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