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AC pressure readings and problem with dealer.

Discussion in 'General Industry Questions' started by Doug580l, Jul 8, 2022.

  1. Doug580l

    Doug580l Senior Member

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    Yes, the door and windows are closed.

    As far as the air recirculating, there is no switch for that but there is foam panel on the hvac side cover.

    This machine does use and expansion valve and they say that they checked it and it's working properly.

    If you go by the service manual, the vent temps and the compressor pressure is not within specs. In the videos I sent the link to the vent temp is about 55 at around 86 degrees outside. Specs are 36 to 53. I haven't checked the compressor pressures since I got it back this time but after the first service it was about 20 on the low side and 165 on the high side and the vents were at 60 degrees. After the second service at 98 degrees out, humid and running for over 30 minutes at full throttle the low averaged about 24 and the high 200. The pressures were better for the first few minutes, L-29 and H-225, that's probably what the dealer is going by. The service manual says that between 86 and 101 degrees the Low should be 15-33 and the High 210-265.

    There are times when the vent temps have gotten down to around 50, but they also seem to fluctuate at times between 50 and 58 or so.

    The vents didn't leak any water until after the second service. There is a lot more water now after the 3rd service.

    As far as I know, all they have done for service is hook it up to a machine and remove and put the freon back in. They also removed 1 drain valve on the second service and another one on the third service. I think they added dye to the system to check for leaks on the 2nd service.
     
  2. Tinkerer

    Tinkerer Senior Member

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    Is there any chance the wrong type of refrigerant has been added to it ?
    Or would that make a difference it there was ?
     
  3. Doug580l

    Doug580l Senior Member

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    One thing I will say about this machine is that the blower is very strong. Seems almost double of what my other machines are. The downside is that it needs to be on the highest setting if it's much over 80 degrees and humid out. And it blows water in my face and eyes. I'm pretty sure that there is no icing going on. There isn't a lot of water draining If I turn the ac off after running for hours.
     
  4. Doug580l

    Doug580l Senior Member

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    As far as another machine, they said they do have another one there and it was blowing a few degrees colder than mine, but they also told me when they dropped it off that all machines are a little different and mine is within specs so they "can't" do anything.

    I mainly got this machine to use instead of a beaten up 1997 case 580. It's got a bent door on it with a big air gap in it and the cab is probably 3 times the size of the mini and it cools better than the mini.
     
  5. Doug580l

    Doug580l Senior Member

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    Do you mean when I added to it? I'm 100% sure I added the right refrigerant, R-134a.
     
  6. Tinkerer

    Tinkerer Senior Member

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    Yes and no.
    The dealership also. They may have used recycled crap.
    Out of desperation I would drain it, do a good vacuum on it and put the correct refrigerant back in, with the exact amount specified in the service manual.
     
  7. John C.

    John C. Senior Member

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    Does your machine have climate control? Can you set the temp on a panel that the system will try to maintain?
     
    mg2361 and Tinkerer like this.
  8. heymccall

    heymccall Senior Member

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    With a TXV system, the anti-icing switch is what cycles the compressor, well, to prevent icing. But, it is also the main regulation of the evaporator temperature.
    On my TB180FR that has underwhelming AC performance, the anti-icing switch is cutting out the compressor long before the evaporator is anywhere near cold enough. Jumper the switch and it'll go 40° vent temps on a 90° day, until it ices over, which is usually less than an hour, if it's any kind of humid out.
     
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  9. fastline

    fastline Senior Member

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    Read back through all that I have put into this thread! I won't retype it. You seem to want to just "change parts", convinced that will solve something. What are you fixing? You don't know! You are also fixated on "vent temps", and I already covered how that mentality is flawed. Either add charge under careful monitoring of temps, pressures, and ounces of charge, or take my other route and blow up the phone! If I need in, and someone won't open the front door, I will go to the back door, then windows, then kick in a door.

    As I mentioned, the water issue is separate and should absolutely be the focus of any dealer convos because it is NOT NORMAL!!! It will require that the AC unit in the cab be opened to expose the evap coil and condensate drain system. It is only then that you will find what is going on.

    Send your videos to Bobcat, and say, "is this what you call a quality machine??? You didn't provide goggles with my new machine delivery"

    You also have a heater core in there and someone already mentioned to ensure that is not causing issues. All you have to do is pinch off the lines to it somewhere, actually just one and it will stop any flow to it, and see if things improve. No need to replace anything.
     
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  10. fastline

    fastline Senior Member

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    Your asking for compressor damage doing stuff like that! part of the reason to cut out the compressor is to ensure there is enough superheat to protect the compressor. A TXV is specifically trying to achieve constant superheat. But I realize in many industries, the motto is "it's fine.....until it isn't".
     
  11. suladas

    suladas Senior Member

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    Agree with others, do not just start replacing parts. They will void your warranty on it, and blame the issue on you. And it's unlikely to fix the issue. If you want to spend money on anything, get an experienced a/c guy to look at the system to see if he notices any issues and get his thoughts on how it preforms. I would also be hounding bobcat to do something better. One machine to the next if exactly the same should be very similar.
     
  12. heymccall

    heymccall Senior Member

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    The bypassing is/ was done while testing only on my TB180FR while the hvac was opened for cleaning.

    But, I have encountered it several times where the anti-icing switch remained closed on my Kenworth W900 trucks (at least 5 times) and I still haven't replaced any of the compressors.
     
  13. Doug580l

    Doug580l Senior Member

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    Might be worth a try. It is interesting that each time it was serviced, they said they removed and put the freon back in with their machine and each time I got it back the ac worked differently.
     
  14. Doug580l

    Doug580l Senior Member

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    No climate control
     
  15. JD955SC

    JD955SC Senior Member

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    Their AC machine’s scale and charging system could be on the fritz as well. I know ours is a 20 year old piece of crap that has to be worked on yearly
     
  16. Doug580l

    Doug580l Senior Member

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    I know I am fixated on vent temps and pressures. That is the only argument I can use with the dealer to try to get them to fix it since those specs are in the service manual.
    If I do replace the freon as Tinkerer suggested I will first add some to see if it makes a difference this time.
    I did email the link to the videos to the dealer. Not surprisingly no reply.
    My wife contacted Bobcat on Facebook today and sent them the videos. They replied and said that someone will contact me. Trying not to get my hopes up, lol.
    I didn't crimp the hoses to the heater core, but I did check the temperature of it with the machine running for a while and it was about the same temp as the surrounding area.
     
    Last edited: Aug 12, 2022
  17. Doug580l

    Doug580l Senior Member

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    I was thinking about hiring someone to check out the ac system. I've been happy with my Case dealer and might call them to see if they would diagnose it.
     
  18. fastline

    fastline Senior Member

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    That would be pure GOLD!!! While it is at the Case dealership, make sure to snap a few pics, post them on Bobcat's FB page saying, "this is how good Bobcat stands behind their product. The guys at Case are a little smarter, they will figure it out"........

    Seriously, I would TOTALLY blast their FB page!!! Before they can even take it down, thousands will see it. Unfortunately this is how anything gets done anymore. Internet blasts.......
     
  19. John C.

    John C. Senior Member

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    I'm guessing then that your system is either on or off? If that is the case, there is no TXV.
     
  20. Doug580l

    Doug580l Senior Member

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    Lol, that's a great idea!