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  1. #1
    Join Date
    Aug 2008
    Posts
    66

    Question NO Filter/Drier - NO Low Pressure Cutout ?

    Hello,

    Is the lack of a filter/drier and low pressure cutouts now becoming the new normal in smaller refrigeration systems? By smaller systems I am referring to refrigerators, window A/Cs, dehumidifiers, etc.

    I recently had an experience with a supposedly high-end dehumidifier that had neither of these devices installed and was surprised to learn this.

    Is it possible to get these systems clean and dry enough during manufacture such that a drier/filter is not required? Or is it just calculated by the manufacturer that the system will be out of warranty by the time that any lurking contamination causes a failure?

    It would appear to me that the lack of a low pressure cutout would basically make any refrigerant leak into a catastrophic leak. If undiscovered the compressor would just pump all of the refrigerant out of the system and the compressor would burn up from lack of refrigerant cooling and/or ingestion of atmospheric moisture from the leak. Is my impression correct?

    Thanks,

    Steve

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,057
    Other than heat pumps and high end A/Cs, not much has low pressure switches. Really sad in these days of POE oil. Most split systems either put a toy strainer in the unit or provide a LL drier to be field installed.

    Never seen either on little guys. Had 2 dead <5 year old whole house dehums in. One was really nice, the board reported an issue based on thermistor readings and shut it down. Really easy to work on, had low side port, TXV. The other brand was murder to access. Nothing shut it down, cap tubes, no tap. Couldn't get at coils. Luckily both were replaced under warranty. Guess even expensive items these days are disposable.

  3. #3
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,271
    The 1982 Carrier air conditioner that is installed on my house doesn't have pressure switches or a filter drier, and it has amazingly kept chugging along every summer for the last 30 years on the same compressor. I would not say this is typical, though.

    Like Loonie says, most stuff does not have pressure switches. Even commercial units don't have pressure switches most of the time, except for walk-ins that use a low pressure control for pump down. I am a bit surprised to hear that you aren't seeing filter driers on the small units, though. I thought that at the least, they all had "copper spun" filters on them. Are you sure that they don't at least have one of those?

    By the way, you may have stumbled upon the answer yourself when you said.. "is it just calculated by the manufacturer that the system will be out of warranty by the time that any lurking contamination causes a failure?". It's sad, but I believe it is more than true with a lot of the junk that is manufactured these days.

  4. #4
    Join Date
    Aug 2008
    Posts
    66
    Quote Originally Posted by BaldLoonie View Post
    Had 2 dead <5 year old whole house dehums in. One was really nice, the board reported an issue based on thermistor readings and shut it down. Really easy to work on, had low side port, TXV. The other brand was murder to access. Nothing shut it down, cap tubes, no tap. Couldn't get at coils. Luckily both were replaced under warranty. Guess even expensive items these days are disposable.
    Would you care to name names for the benefit of other members on this board? If not can I contact you directly? I may be in the market for one of these in the near future.

  5. #5
    Join Date
    Aug 2008
    Posts
    66
    Quote Originally Posted by ammoniadog View Post
    I am a bit surprised to hear that you aren't seeing filter driers on the small units, though. I thought that at the least, they all had "copper spun" filters on them. Are you sure that they don't at least have one of those?
    I am not sure. What does a "copper spun" filter look like? Is it part of the compressor assembly or piping? A picture would be helpful here.

  6. #6
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,271
    Quote Originally Posted by Steve 347 View Post
    I am not sure. What does a "copper spun" filter look like? Is it part of the compressor assembly or piping? A picture would be helpful here.




    They look something like this and are usually found in the liquid line between the condenser and cap tube.

    Name:  Copper_Filter_Drier_with_Spun.jpg
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  7. #7
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,057
    Steve, shoot me an e-mail.

  8. #8
    Join Date
    Aug 2008
    Posts
    66
    Quote Originally Posted by BaldLoonie View Post
    Steve, shoot me an e-mail.
    Sent... To the email address in your profile. So far it hasn't bounced back.

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