----- Original Message ----- From: "Harry Watkins" <[EMAIL PROTECTED]> To: "Marshall Booth" <[EMAIL PROTECTED]> Sent: Sunday, July 16, 2006 10:34 AM Subject: Re: [MBZ] Need AC help on 86 SDL
> Marshall > > You're right as usual, regarding the dryer fan switch, the ACC Supp shows > what you said, pressure signal, closed 20 bar, open 15 bar, however, I'm > pretty sure this was written for R12. > > Was this information from a TSB? > > Is there a link to Mercedes TSBs we can use? > > On the SDL that was cooling great a couple of weeks ago, I am hopefully > looking for a quick fix, maybe the new KLIMA, who knows. BUT: > > I have another SDL that will be a complete whatever it takes type thing and > I want to go into it with eyes wide open. > > The info from you and the people on the autoacforum seem to have sources > more up-to-date than I have and I need to tap into all I can. > > BTW, didn't you and DaveM have a thread discussion about tweaking the ETS a > couple of years ago? > > Two things that bohica wrote that took me back was the test would be with > the doors closed and the windows open, WHY? The other is to take your gauge > and vent temp readings after ten minutes at 2000 RPM. That makes sense. > > This stuff ain't simple to me. > > Many thanks. > > Harry > > > > > The Temperature Switch on the dryer starts the aux fan at > 55c. It should open again by 12c . > > > > There is at least ONE problem with the information that was provided. > > There is NO temperature switch on the drier (as there was in the older > > 300SDs). Instead, there is a pressure switch that turns the aux fan on > > at 280 psi (~20 bar) with the "green" switch intended when R-12 is used > > and at 250 psi (~18 bar) when replaced with a red switch (intended to be > > used when R-134a is used). In addition, there is an evaporator > > temperature sensor (ETS) that is set to shut the compressor down when > > the evaporator temperature drops below about 5 deg. C (~41 F) when the > > system was new. As the system ages it is usual for the ETS trigger temp > > to creep up so that 45-50 deg F is NOT unusual after 15+ years and I've > > seen them get so high the compressor would NEVER switch on. > > > > I was pleased to see the information about ambient temp and humidity and > > the effect of pressures, but without REALLY accurate information on temp > > and humidity, it's difficult to use it as a measure of "proper" charge. > > > > Marshall >
