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A/C Thermostat Switch

Discussion in '206/246' started by DinoDriver, Apr 2, 2009.

  1. DinoDriver

    DinoDriver Formula Junior

    Mar 14, 2005
    537
    Leesburg, VA
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    Bill Ebert
    #1 DinoDriver, Apr 2, 2009
    Last edited by a moderator: Sep 7, 2017
    I was in the process of replacing the choke slide control bezel on the center console just in front of the emergency brake handle. This requires getting access to the choke cable under the console. When you lift the console, which contains two a/c control switches (vent fan speed and a/c temperature adjustment--it's a kind of thermostat), you also stretch the delicate capillary tube between the temp adjustment switch and the evaporator area. Well, let's just say I got a little too rough with that tinny-weeny tube - - it broke. Pictures attached. The switch is branded as "Ranco" "Slenderstat" part number A50-2288. There's quite a bit of info on FChat about 308s and 328s that have this problem, but nothing on Dinos. Anybody have a source for this Dino part or a substitute? I get a couple hits on Google but nothing this specific.

    Thanks for your help,

    Bill
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  3. DinoDriver

    DinoDriver Formula Junior

    Mar 14, 2005
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    Bill Ebert
    #2 DinoDriver, Apr 21, 2009
    Last edited by a moderator: Sep 7, 2017
    Happy to report that I did find an a/c thermostat switch in stock at Dennis McCann's (All Ferrari Parts, Inc). It's his P/N 109253 for $106 with S&H. The only difference from the original is a much longer capillary tube than required for a Dino, most likely because it also fits 308s 328s, Daytonas, 365GTC/4, 410s, etc. Since there is very little info on this repair procedure on this forum, I took a bunch of pix in case someone else is as ham-handed as me and breaks the capillary tube when messing around under the center console.

    So, first pix shows what's behind the passenger's footrest. The original capillary tube is broken - - out of the picture, lower center. You get to this a/c area by removing the small screws holding the center console to the floor, removing the two large screws holding the shift lever gate in place and carefully raising the console. Removal of the shift knob is optional. Remove the a/c thermostat switch from the console (on my Dino , it is the one on the left, closest to the shift lever) by loosening the small set screw in the knob with an Allen wrentch, remove the knob, remove the locking nut which was below the knob and the switch will likely fall down and out of the console. Remove the two wires from the switch -- mark which wire goes where on the new switch. Next remove the small screws holding the forward portion of the console to the floor and carefully lift and twist that piece from behind the accelerator pedal. Next you must unscrew two large panhead machine screws that are at the very bottom of the vertical portion of the passenger's foot rest, under the carpet. Once that is done, you can squeeze your fingers along the top and left side of the footrest (alongside the accelerator) and swing the footrest fiberglass board and carpet toward the passenger door. Now you should see exactly what's in this first pix. The good news is that the thermostat bulb is not embedded in black "cork tape" wrapped around the body of the expansion valve. Instead, it's neatly placed in a sleeve that is embedded in the evaporator air stream. At least, I think that's what I am looking at. Pix #2 is a close-up. Please comment if this is incorrect. The bad news is that if this is correct, I really don't understand its function. I can't imagine a block of ice forming around it where it is now and signaling the a/c to shut down until the ice melts. That would be impressive in a Dino! :)

    Pix#3 shows the new switch and capillary tube about to be installed. Too much tubing but I doubt that will be a problem as long as I don't kink it or get it near that electrical coil mounted on the back of the footrest. I coiled it more tightly than shown and rested it on the lower left side of the evaporator screen with one piece of electrical tape holding the straight section going from the evaporator to the center console along the top of the tunnel. Then I just reversed everything to put it back together.

    Pix #4 shows everything in place. The a/c seems to work fine but I really won't know until a really hot humid day in July-August. Wish me luck!

    Hope this helps.

    Bill
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  4. fuji0030

    fuji0030 Rookie

    May 25, 2009
    1
    first pix shows what's abaft the passenger's footrest. The aboriginal capillary tube is torn - - out of the picture, lower center. You get to this a/c breadth by removing the baby screws captivation the centermost animate to the floor, removing the two ample screws captivation the about-face batten aboideau in abode and anxiously adopting the console. Removal of the about-face bulge is optional. Abolish the a/c thermostat about-face from the animate (on my Dino , it is the one on the left, abutting to the about-face lever) by alleviation the baby set spiral in the bulge with an Allen wrentch, abolish the knob, abolish the locking nut which was beneath the bulge and the about-face will acceptable abatement down and out of the console. Abolish the two affairs from the about-face -- mark which wire goes area on the new switch. Next abolish the baby screws captivation the advanced allocation of the animate to the attic and anxiously lift and aberration that section from abaft the accelerator pedal. Next you have to alleviate two ample panhead apparatus screws that are at the actual basal of the vertical allocation of the passenger's bottom rest, beneath the carpet.

    _________________
    Thermostat
     
  5. DinoDriver

    DinoDriver Formula Junior

    Mar 14, 2005
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    Bill Ebert
    Huh?
     
  6. Jon Hansen

    Jon Hansen Formula Junior
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    #5 Jon Hansen, May 25, 2009
    Last edited: May 25, 2009
    Bill,
    I'm guessing someone used a language translation program on your original message text.
    Second guess; drugs
    Thanks for posting, I have a broken capillary tube also and this will help.
    Jon
     
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  8. DinoDriver

    DinoDriver Formula Junior

    Mar 14, 2005
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    Jon, good guess on the language translation program. I just noticed it's fugi0030's first post as a Rookie so that would make some sense.

    Good luck with your repair. If you can't find the part, let me know and I'll check my notes on other sources.

    Bill
     
  9. Jon Hansen

    Jon Hansen Formula Junior
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    Feb 6, 2007
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    Question; Why can't one just sleeve the broken tube together and solder the connection back to air tight? As long as the capillary tube is not plugged, shouldn't this fix work?
     
  10. DinoDriver

    DinoDriver Formula Junior

    Mar 14, 2005
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    Bill Ebert
    Jon, not quite that simple or that's what I would have done. These capillary tubes are filled and sealed with a "exotic" gas which transmits very small pressure/temperature changes to the thermostat switch on your console. My research told me the gas is usually ammonium. So as the temperature of that bulb at the end of the tube where it's inserted into the evaporator reaches 32 degrees (you should be so lucky in the Dino! :) ), the thermostat automatically turns the system off. Otherwise, ice will block the flow of air through the evaporator and the system will keep running but you'll not get any cooling air. Your proposed fix would result in ambient air in the tube and the thermostat would not receive a "signal" from the temperature sensing bulb. So, the question is: Should you spend the $106 for the new thermostat switch/capillary tube and install it per my instructions or just leave the "broken" thermostat switch in the full "On" position (rotated full clockwise) and hope the evaporator core never freezes over. IMHO, I doubt that evaporator core on a Dino will ever freeze over. If your system is working REALLY well and the humidity is high this could happen. When is does happen, you could simply turn the thermostat switch full counter-clockwise to "Off" for several minutes to allow the ice to melt, then back "On." If the system comes back on and is cold, ice was the problem. If not, you have another problem.

    I'm no expert on this matter, so others with more experience, please chime in with advice.

    Bill
     
  11. eoirlev

    eoirlev Rookie

    Dec 18, 2020
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    Israel
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    Ram levinson
    Hi Dino
    can you please help me find an alternative A/C thermostat (compatible to Ranco A50-2288) to my classic Alfa Romeo
    thanks
    Ram (ram.levinson@gmail.com)
     
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  13. eoirlev

    eoirlev Rookie

    Dec 18, 2020
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    Israel
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    Ram levinson
    Dear Bill
    did you find an alternative thermostat for the Ranco A50-2288 ?
    please advise
    Ram (ram.levinson@gmail.com)
     
  14. synchro

    synchro F1 Veteran

    Feb 14, 2005
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    Scott
  15. eoirlev

    eoirlev Rookie

    Dec 18, 2020
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    Israel
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    Ram levinson
  16. synchro

    synchro F1 Veteran

    Feb 14, 2005
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