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  1. #1
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    Fridge Problem..frost on suction line, and cooling is not good


    hello all..

    I have a small deep freezer and a topmount no-frost fridge..

    Fridge compressor died last year, while the deep freezer stopped freezing stuff, so I started using is as a fridge.

    I decided to fix them, so I got a guy who replaced the fridge compressor, and recharged gas for both the fridge, and the deep freezer.

    After using them, I found that:

    -The suction line in both of them (the line from the box to the compressor) started to ice up after a few minutes..
    -Cooling in both is not good.. the temperatures of both appliances are between 15-30F.
    -The fridge takes ages to power off. I took the thermodisc off and tested it, and it works just fine.

    I asked around and someone told me that they are overcharged with gas. so, part of the cooling power is wasted cooling the suction line instead of cooling the evaporator. therefore, frost build up, and cooling not so good.

    I wasn't gonna use the deep freezer any time soon, so I thought I'd experiment with it. so, I used the valve (which the guy installed in the compressors) to release some gas.. but the frost on suction line never went away..

    Any advice??



  2. #2
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    Re: Fridge Problem..frost on suction line, and cooling is not good

    Time to get the same guy back to balance the refrigerant charge and sign off on your job.. Mike.
    To the optimist, the glass is half full. To the pessimist, the glass is half empty.

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    if it was that easy, I would have done it already.. he works -among other technicians- in a company.. I cant reach him personally, and I don't wanna pay for another visit from another technician because I lost confidence in the whole company.

    I need to understand what the hell is wrong with it before I get anybody.. perhaps I can fix them myself.

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    He did not fixed it properly, so you have right to ask them to make their job properly and without any compensation for that. We call that "callback".
    Confidence or not, it is your money. You already paid for fixed FF. Call them to deliver in full already paid service.

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    Guys.. I promise you its not easy. I thought this through

    I can ask them to send someone to fix it without paying labor, but if the technician tells me that they need some parts, I'd have to pay for them.

    That's why I'm hopping that you help me diagnose the problem before bringing anyone and paying him money.

    so, can anyone help me find out whats wrong with these appliances?

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    Quote Originally Posted by hunted22 View Post

    -The suction line in both of them (the line from the box to the compressor) started to ice up after a few minutes..
    Suction line in fridge and freezer could be partially iced, but fridge suction line near compressor should not have ice.
    Where exactly icing stops at both fridge and freezer?


    I asked around and someone told me that they are overcharged with gas. so, part of the cooling power is wasted cooling the suction line instead of cooling the evaporator. therefore, frost build up, and cooling not so good.
    That is not correct explanation what is happening when we get overcharge.

    Line is frosting because there is no or very little superheat in evaporator and suction line because all refrigerant is not evaporated in evaporator. Since there is negative temperature inside fridge or freezer (you said 15-30F) and liquid/gas mixture is exiting from evaporator you must have frost at suction line (which is at saturation temperature of refrigerant).
    That possible liquid/gas mixture or not enough superheated gaseous refrigerant in suction line, which causes frost, could be because of few reasons
    • Heavy frosted heat exchanger
    • Faulty evaporator fan (if present)
    • Dirty heat exchanger
    • Overcharge of refrigerant
    • To litle restriction on expansion device (if compressor is not same displacement as original one)


    You need to confirm that first 3 are not issue and tell us where frost ends at suction line for both apliances.

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    Hi nick.. thank you for taking the time to explain

    Quote Originally Posted by nike123 View Post
    Suction line in fridge and freezer could be partially iced, but fridge suction line near compressor should not have ice.
    Where exactly icing stops at both fridge and freezer?.
    I'd say the whole suction line ice up in both.. specially near the compressor. it only stops when meet with the heat of the compressor and melt on it.
    The only part of the suction line in both appliances that doesn't form that much ice is where the suction line meets the capillary tube that is coming from the filter to the evaporator.

    Quote Originally Posted by nike123 View Post
    That is not correct explanation what is happening when we get overcharge.

    Line is frosting because there is no or very little superheat in evaporator and suction line because all refrigerant is not evaporated in evaporator. Since there is negative temperature inside fridge or freezer (you said 15-30F) and liquid/gas mixture is exiting from evaporator you must have frost at suction line (which is at saturation temperature of refrigerant).
    That possible liquid/gas mixture or not enough superheated gaseous refrigerant in suction line, which causes frost, could be because of few reasons
    • Heavy frosted heat exchanger
    • Faulty evaporator fan (if present)
    • Dirty heat exchanger
    • Overcharge of refrigerant
    • To litle restriction on expansion device (if compressor is not same displacement as original one)


    You need to confirm that first 3 are not issue and tell us where frost ends at suction line for both apliances.
    Alright.. some of that went over my head, but here we go..

    -Faulty evaporator fan (if present)
    no fan in the freezer, and fridge fan is working smoothly

    -Heavy frosted heat exchanger
    -Dirty heat exchanger

    Not sure what you mean by "heat exchanger".. I'm guessing you mean the condenser, which is little dusty but fairly clean, and not icing.. tubes are hot near the compressor, and room temperature near the filter.

    If you meant the evaporator, it is also clean and not icing.. in fact, in like 5-10 minutes of powering the fridge or the freezer on, the suction tubes start to look really white due to the frost, while you cant see any ice forming on the evaporator for hrs.

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    Quote Originally Posted by hunted22 View Post
    in fact, in like 5-10 minutes of powering the fridge or the freezer on, the suction tubes start to look really white due to the frost, while you cant see any ice forming on the evaporator for hrs.
    I would say that point to probable restriction in capillary/filter drier.
    Check if condenser is hot to touch at top (where line is coming from compressor) and at ambient temperature at bottom where it meet filter-drier and report findings. Also try to determine how much of condenser is at an ambient temperature.

    Does technician, when he was changed compressor, changed also filter-drier? Also did he measured end vacuum with separate vacuum measuring instrument or he just vacuumed some time without measuring vacuum.

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    oops.. sorry.. meant nike

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    Quote Originally Posted by nike123 View Post
    Check if condenser is hot to touch at top (where line is coming from compressor) and at ambient temperature at bottom where it meet filter-drier and report findings. Also try to determine how much of condenser is at an ambient temperature.
    the condenser temperature from compressor to filter goes like this..

    %55-60 is REALLY HOT to hot.. %15 warm.. %20-15 ambient.. while the suction line near the compressor is as cold as the evaporator.. maybe colder.


    Quote Originally Posted by nike123 View Post
    Does technician, when he was changed compressor, changed also filter-drier? Also did he measured end vacuum with separate vacuum measuring instrument or he just vacuumed some time without measuring vacuum.
    Yeah he did change filter, and installed a valve.

    I wasn't around all the time after he finished welding.. but I recall him talking about using the manifold to measure pressure after vacuuming, and after charging.

    I don't recall seeing a vacuum though.. what I understood from the portions I observed is that he welded everything and installed the valve.. then used the running compressor to vacuum itself.. but that is what I put together from what I saw.. is that even possible?

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    It looks like it is overcharged.




    Did he weighed charge, charged from glass cylinder



    or charged by monitoring only suction pressure?

    Last is recipe for overcharging.
    Last edited by nike123; 20-04-2011 at 10:02 AM.

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    Hi nike. thank you for the detailed answer..

    actually yeah.. he didn't weigh the charge.. he charged from a can...

    Thanks to you, I actually got bolder these past few days after reading your last post, and released more gas, and the freezer actually stopped forming ice on the suction line, and the temprature went from being 14F to 4F.. which is quite an improvement..

    I'm glad about this, but I dont know if I should release more gas -as I hear that deep freezer temprature is lower than 0F- or thank my lord and stop..

    What do you think?

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    Try to release more but smaller amount and see if temperature goes down more. When you don't see any change, you are probably at correct amount.

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    Quote Originally Posted by nike123 View Post
    Try to release more but smaller amount and see if temperature goes down more. When you don't see any change, you are probably at correct amount.
    I didn't really want to stick my nose in here for several reasons BUT... without gauges connected, one press of the valve will be too many eventually, and air will be sucked in, then it's all over.
    To the optimist, the glass is half full. To the pessimist, the glass is half empty.

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    Re: Fridge Problem..frost on suction line, and cooling is not good

    I'll try to be careful.. I'll probably give it a single push for a few seconds, if I didn't see any improvement, I'll just stop.


    Guys.. I'm having a different problem now..

    After the result I've gotten with the freezer, I thought to try the same with the fridge.. I powered the fridge or an hour and wrote down temperature, time, thermostat level, .. etc.. and then I started to release some gas..

    I didn't pushed the the valve for long.. like 4 or 5 seconds and removed my finger. and I found some oil on it. apparently some of the compressor oil escaped from the valve while I'm pushing it. that did not happen with the freezer.

    I just closed the valve, and after a few minutes I powered the fridge off and I thought to ask you what the hell is going on?? I didn't mess anything up, did I?

  16. #16
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    Re: Fridge Problem..frost on suction line, and cooling is not good

    First stop fridge for 5-10 min. and then release some gas. No more than 2-3 sec. That way you cannot suck any air in system.
    Oil, in small amount you described, is not problem.

    Be aware that liquid refrigerant could cause frostbite and oil in eyes is dangerous. Released refrigerant damage our environment and it is against the law in some countries to do it on purpose.

    Don't hold me responsible for any damage.

  17. #17
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    Re: Fridge Problem..frost on suction line, and cooling is not good

    I really think that's above and beyond.
    OP wanted to know what's wrong and to work something out before asking the repairer back.
    If what is done so far has yielded results, there's not much further they can go.
    The fridge needs a good evac with a vacuum pump and a precise weighed in refrigerant charge. Stuffing around at this point isn't doing any good. Nothing personal OP, but try claiming warranty for the compressor you paid for if the supplier knew you are removing refrigerant and possibly letting air into the system and losing oil too.
    Let alone the legal aspect which is an insult to most members here who are bent over a barrel in regards to trade practices, the law, equipment and training we have to pay for etc.

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