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  1. #1

    Mini Split Heat pump Problems.

    I have had a BonAir mini split 18000 btu heat pump system since 2007. (company is gone) I installed it myself in my office, separate building. This past summer it started freezing up on the condenser, inside. It would cool ok for a couple hours but slowly freeze up. I put an indoor/outdoor thermostat on its output.
    I would get 20 degree difference when it was working before it would freeze up. I would turn it off until the ice melted then it would be ok again for a couple hours.
    I figured it was low on freon, which means a leak, I figured I would get it looked at next spring. However since it has turned cold I have been running the heat pump, even down in the single digits it works perfect. Of course it has to defrost when its in the teens and single digits but it warms the office just fine. 25-30 degree temp difference. So now I figure maybe something is wrong with the reversing valve. Tonight I turned on the air and its only blowing 12 degree difference.
    Any Ideas what the problem is?

  2. #2
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,941
    Nope. No more then my doctor can tell me why my leg hurts so bad tonight from his office.

    Are you an HVAC technician? If so, you should know that just because your heating is working does not mean it is working perfectly or even properly.

    Even though this is not a DIY site, I will ask if you insulated both refrigerant lines and did you put a filter drier in the smaller line?
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  3. #3
    Yes I insulated the lines, It was a pre-charged unit with new filter, I also flushed the lines after I flared the ends and pumped it down.
    I said its been running since 2007
    After 3 years running fine why would line insulation or a filter matter now anyway.? Its obviously a failure of some kind. In my experience the ice build up indicates low freon normally which means a leak. I figured it would also affect the heat pump. No I'm not certified but I have gauges and since I cant legally buy freon I'm forced to hire someone to charge any air condition, unfortunately there are plenty of bad technicians out there with licences, so I prefer to do what I can myself and I also prefer to know what to expect before I do.
    I didn't realize this was a closed group.
    Sorry

  4. #4
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,941
    Quote Originally Posted by larrylwill View Post
    Yes I insulated the lines, It was a pre-charged unit with new filter, I also flushed the lines after I flared the ends and pumped it down.
    I said its been running since 2007
    After 3 years running fine why would line insulation or a filter matter now anyway.? Its obviously a failure of some kind. In my experience the ice build up indicates low freon normally which means a leak. I figured it would also affect the heat pump. No I'm not certified but I have gauges and since I cant legally buy freon I'm forced to hire someone to charge any air condition, unfortunately there are plenty of bad technicians out there with licences, so I prefer to do what I can myself and I also prefer to know what to expect before I do.
    I didn't realize this was a closed group.
    Sorry
    "It is obviously a failure of some kind." This statement alone tells me you really should have someone who knows what they are doing check out your system.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  5. #5
    I already figured that out sometime ago, Maybe where you live you can trust every service company and service man. It would be nice if everyone is honest. I want to have an idea of what is wrong before I give cart blanch to some company or technician. You may be honest but everyone is not created equal. I have been around long enough to have encountered both types. The company that installed the whole house unit will not touch an air condition that they didn't install so I'm at the mercy of the phone book. Before I moved up here I installed my last 2 units Goodmans and had a local guy do the initial charge. I lived there 19 years. Since I moved here 3 years ago I don't know an honest tech or company. Unlike most other products the Government has made air conditioned service a private club. Thank you for your answer but I will continue to find out the possibilities before I call someone.

  6. #6
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,941
    The government has not caused HVAC service to be the way it is anywhere near as much as the diverse nature of the industry causes HVAC to be more professsional neccesary then most other trades.

    I understand your apprehension, so allow me to give you the basics that could be causing your issue. Freezing evaportator coils are caused by one of two basic situations; low refrigerant entering the coil or low airflow across the coil. Since there are many different reasons for either of these causes, to determine exactly what is going on requires on the site inspection and testing.

    And yes, even having operated without freezing up for years, if the small line of the refrigerant lines was not insulated or if both lines are insulated together in the same insulation, the system could very well have operated, albeit not efficiently, without issue until several factors came together to cause the coil to freeze.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  7. #7
    They are separate insulation and only about 10ft long. I have tried to change the airflow over the coils and only the top of the evaporator gets iced up, when it was working I was getting about 20 degrees air temp from in to out. After it iced up and I defrosted it I would still get 20 degrees, however last night it was more like 14 degrees, so what ever the problem its getting worse. It just baffled me that the heat pump is operating at peak efficiency still. So I figure its more than just freon. The other problem is not every dealer around her know much about mini splits because they haven't installed any or very few and they don't always tell the truth when you ask. I have asked how they charge one and the answer is with gauges and pressure diff. None have said by weight.

    The house Air was under warentee when we bought the house, last year both 2x4s holding it off the ground hanging under the house broke and was leaking water under the house causing my insulation to drip water. Then it quit cooling. They sent out a new tech and he charged it up and 5 minuets later it was all gone, so he spent about 4 hours looking for the leak which was on the compressor line close to the compressor. Then used metal straps to re strap it back up. He had to make several phone calls all in all about 5 hours. He had 2 other guys come to look. I would of hated to have to have paid for 4-5 hours of that. I was recuperating from surgery the day before. The company is rated A+ at the BBB, they are the ones that will not look at the mini split because they did not install it.

  8. #8
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,941
    You are still making assumptions, and that is a very dangerous thing to do with an HVAC system. Don't know what else to tell you at this point.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  9. #9
    Quote Originally Posted by RoBoTeq View Post
    You are still making assumptions, and that is a very dangerous thing to do with an HVAC system. Don't know what else to tell you at this point.
    The only assumption Im making is that if its low o freon it has a leak, I have never seen one that looses freon without having a leak.
    thank you for your help

  10. #10
    Join Date
    Oct 2010
    Location
    AZ
    Posts
    644
    Quote Originally Posted by larrylwill View Post
    They are separate insulation and only about 10ft long. I have tried to change the airflow over the coils and only the top of the evaporator gets iced up, when it was working I was getting about 20 degrees air temp from in to out. After it iced up and I defrosted it I would still get 20 degrees, however last night it was more like 14 degrees, so what ever the problem its getting worse. It just baffled me that the heat pump is operating at peak efficiency still. So I figure its more than just freon. The other problem is not every dealer around her know much about mini splits because they haven't installed any or very few and they don't always tell the truth when you ask. I have asked how they charge one and the answer is with gauges and pressure diff. None have said by weight.
    Where do you live? Maybe there is someone on this forum that is close by or knows someone.

    I agree with you some people are stupid, lazy, or dishonest and others are good at what they do and sometimes it is hard to find the good ones. This is the same for doctors, lawyers, and everything else though. But just as Robotec says there are multiple possible causes the only way to find out is to test the system on site. It is very possible low freon is not the problem so it wouldn't be a good idea to just start adding it even if you could get some unless you test it. Heat pumps sometimes work while heating and not cooling for other reasons. If you go adding it when it doesn't need any it will screw things up worse. So it may be what you were thinking or it may be a bad part. That is the best I can tell you for what to expect. And, yes, there can be combinations of problems sometimes too.

  11. #11
    across the river from Scottsboro Alabama.

  12. #12
    Join Date
    Apr 2010
    Location
    Ontario
    Posts
    474
    Might be easier for you to throw the ac out and install a brand new one like you did before.
    ENJOY THE RIDE

  13. #13
    Join Date
    Nov 2000
    Location
    Eastern PA
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    Quote Originally Posted by larrylwill View Post
    The only assumption Im making is that if its low o freon it has a leak, I have never seen one that looses freon without having a leak.
    thank you for your help
    Well, I have seen many systems that have low refrigerant in the coil that do not have a leak.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


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