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HVAC A/C error, pressure loss, refrigerant type?

Discussion in 'Model S: User Interface' started by scottm, May 25, 2018.

  1. scottm

    scottm Active Member

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    My car periodically started giving me a popup and error, that has turned into a perma-error.

    I had Tesla teleport a repairman into the wires of my car and he came back out and told me "low pressure sensor".

    I pulled the frunk bin out and see the A/C compressor sitting there with oily stains around some of the plumbing port/s. So, yep, looks like she's leaking. Could be a half-turn of tightening, or a new gasket.. I'm hoping it's that simple.

    My mechanic would like to know what kind of refrigerant this machine takes? No guesses, exact spec if you know - thanks in advance!

    (I'm off warranty and 3 hours away from a service center and my mechanic is an expert with A/C repair and has all the proper equipment for diagnosing leaks, purging, and replacing refrigerant... just want to be sure of type).

    It's a 2014 model S mid-year build with a VIN range P509xx

    Tesla HVAC2.jpg
     
  2. scottm

    scottm Active Member

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    I guess a quick second question is .... amount of refrigerant for the system?

    This is a RWD car with dual on-board chargers, if that makes a difference.
     
  3. Ingineer

    Ingineer Electrical Engineer

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    Depending on its intended sales region, the air conditioning system is filled with R134a or 1234yf refrigerant. Refer to the label on the RH frunk trim. (U.S. and most markets use standard R134a)

    If oil needs to be added to the system, use only POE ND-11 or equivalent. This is vitally important! You cannot use recharging hoses or equipment that's been used for standard PAG type oils used in most cars. This is because the PAG oil is electrically conductive and if put into the high-voltage electric compressor used on the S/X/3, it may cause a high-voltage isolation fault and the car will not drive. POE oil is the same as used in a Prius and most other modern hybrids, so it should be easy to find a shop that can do it.

    Capacities:
    Air conditioning refrigerant (systems using R134a) 1.70 lb (1.66 lb minimum, 1.74 lb maximum) 770 g (750 g minimum, 790 g maximum)
    Air conditioning refrigerant (systems using R1234yf) 1.61 lb (1.57 lb minimum, 1.65 lb maximum) 730 g (710 g minimum, 750 g maximum)
    POE Air conditioning oil 5.3 oz (weight) 150 g
     
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  4. scottm

    scottm Active Member

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    #4 scottm, May 25, 2018
    Last edited: May 25, 2018
    Aaaawesome thanks!

    This is a Canadian car. My guess is this makes me a R134a. I didn't know to look on frunk trim for this kind of information, but sort of thought it should be lurking on a sticker somewhere on the car ... will look for it.

    I just got off the phone with Tesla... all techs busy but the service concierge did her best to gather the following advice from techs talking over their shoulders and she relayed this to me on the phone:

    - make sure the servicing shop is HV (high volttage) trained
    - use non-conductive oil
    - we "add 50 grams" of oil if there was a leak


    My mechanic is HV trained, works on hybrids, and knows what orange cables mean! Keep one hand in the pocket.
     
  5. scottm

    scottm Active Member

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    #5 scottm, May 28, 2018
    Last edited: May 28, 2018
    Well I found the leak...

    Hooked up the A/C charge machine to the input and outputs found easily under the cowl, nice easy access just one trim panel. (But I had already removed the whole frunk to have a look around.)
    Zero A/C pressure showing on the machine.
    Applied a vacuum and showed a slow leak.
    Pressured up the system to 1.7 pounds of gas.
    Ran A/C and began blowing nice and cold again...
    Eventually the front grills opened and fans spun up ... moving a lot of heat through the system.
    Stopped the A/C, everything quieted down.
    Then using a refrigerant sniffer found the driver's side condenser to be leaking.. the detector went to the wall with lights and sounds!

    But the dead give-away was oil dripping from the driver's side condenser made a little puddle just ahead of the tire.

    After a couple hours, I had the error come up on dash again... lost all pressure again.

    Looking through the actuated grill at the font of the condenser didn't show any obvious rock damage.

    Access to the condenser is made easier by a front portion of the fender liner coming out. Gotta get the fan off the back of it, then take a look at the condenser closely.

    I'll do that next and have a look to see if the leak is from the fins, or along a seam, or at connectors for the hoses. With any luck it's a loose connector hose or blown gasket. That'd be better than needing a new condenser.

    I'll keep this thread updated.

    One thing for sure, no more attempting to run the A/C until this is fixed don't want to spill all my oil. Not good for an A/C compressor to run dry I'm told. When the warning is up on the dash, it's possible to select "A/C ON" but the compressor won't spin up. Self-protecting when zero pressure is detected. Good thing!

    Big question in my mind right now is what happens at the supercharger if I try? Will the charge rate just be limited, or a no-go?
     
  6. scottm

    scottm Active Member

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    #6 scottm, Jun 4, 2018
    Last edited: Jun 4, 2018
    The car supercharged fine in the 23C ambient temp... it hit the normal peak kW charge rate for the 40% battery SOC I was at, and it continued on normally and reached the 90% target in normal amount of time.

    Here's the picture of the leaking pipe near the front condenser ... as viewed from front left wheel well, with front fender liner removed. Looking forward from the wheel hub (that's my brake disc in the foreground).


    ...the oily stains at the junction between the aluminum pipe and rubber hose, this crimp ... is no longer holding A/C pressures - typically up to 250 psi


    IMG_0596 - Copy.JPG

    This pipe is one long continuous piece that goes from the outboard side of the condenser right back to the A/C pump. A long and complicated thing with bends and supports and transitions from tube to hose to tube to hose.. and here you can see a sensor mount attached... along the way.

    Then the pipe turns up into the bottom side of this big accumulator bulb that is very close to the A/C pump which is where I spotted the part number


    Here's the part number TMN (Telsa Motors Number) 1028401-00-E ..

    I was thinking of trying to repair the line, but found the Tesla part price reasonable CAD$216 for the whole complicated thing... so I'm going OE part and getting it done by Tesla.. they'll have to refill the oil and pressure the system up again.

    IMG_0604 - Copy.JPG
     
  7. MP3Mike

    MP3Mike Well-Known Member

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    If it is just the pipe to hose connection that is bad any competent A/C shop should be able to rebuild that pipe/hose unit. (Probably cheaper than you could buy the part.)
     
  8. scottm

    scottm Active Member

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    The pipe is aluminum, if it were steel shops would be more eager to touch it for repair.

    I was turned away from a few A/C shops over the phone because they don't like touching automotive aluminum A/C lines. One of them advised, compression fittings won't cut it...must be brazed.

    Ever tried heating aluminum to braze it? Touchy.
     

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