RE:

["Duff, Ian" <IDuff@charter.com>]

Bentley 87.2 has a warning that "Refrigerant system has no sight glass.
System must not be topped up. If low refrigerant charge is suspected,
system must be completely discharged, evacuated, and recharged with
1050g + 20 g (37.0 oz + 0.7 oz) of R12 refrigerant."

Surfing Bentley does not uncover any indication of high pressure switch
activation cycle times, so I would guess "too often" is a subjective
term. My system does a complete - compressor start due to insufficient
pressure, compressor increases pressure sufficiently to cause compressor
to be switched off, pressure gradually drops triggering low pressure
switch - cycle over about 15 seconds, of which compressor on time is
frequently in the 5 second range.

My guess is that if you are in the 15 second range, with about 1/3 of
that having the compressor active, you are OK. Significantly outside
this, get your system evacuated, checked for leaks, fix any, and
recharge. I did just that last summer, cost about US$230, including an
evacuation and leak locator, weld holes in A/C condenser, and recharge.
It's fine so far this summer, so hopefully I've got it. HTH.

-Ian Duff.
	-----Original Message-----
	From:	Mark Zvolanek [SMTP:mzvolane@sydney.ipex.com.au]
	Sent:	Friday, August 22, 1997 12:33 PM
	To:	Duff, Ian
	Cc:	'quattro@coimbra.ans.net'
	Subject:	RE:


	Ian
	Thanks for your reply.
	Most people say that if A/C high pressure sensor  clicks too
often, it's   
	caused by not enough gas in the A/C. How often should the A/C be

	refilled? Is the any other way of testing the amount of gas in
the A/C.
	Mark.

	 -----Original Message-----
	From: Duff, Ian [SMTP:IDuff@CHARTER.com]
	Sent: Friday, 22 August 1997 03:07
	To: Mark Zvolanek; 'quattro@coimbra.ans.net'
	Subject: RE:

	Clicks are the high pressure sensor activating or deactivating.
R12
	pressure falls below threshold sensor is set to, it clicks,
compressor
	goes on, engine seems to lose a little power, next click says
R12 is
	sufficiently compressed, so compressor switches off and engine
regains
	power, R12 gradually loses pressure, pressure falls below
threshold
	sensor is set to, it clicks, compressor goes on, and so on and
so on. My
	'90 CQ does the same thing.
	 -Ian Duff.
	 -----Original Message-----
	 From: Mark Zvolanek [SMTP:mzvolane@sydney.ipex.com.au]
	 Sent: Tuesday, 19 August 1997 1:57 PM
	 To: 'quattro@coimbra.ans.net'
	 Subject: 


	 Gday again Audi fans.
	 When I switch the aircon ON, I can hear clicks coming from the
	area of
	 glove box, click repeates every 15 or so seconds, and at every
	second
	 click engine looses little power, then it gains back the power
	at the
	 following click. Apart from that the A/C seems to work OK.
	 What might be causing that? Any help will be welcome.

	 /\/\ark Z\/0LANEK
	 '91 90 man non-Q