Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Low voltage heating element

  1. Dec 31, 2012 #1
    Hi there!

    I recently noticed that the little drainage tube in the back of my fridge keeps blocking up with ice. As a result massive condensation develops around the ice which eventually drips down the back causing the bottom of the fridge to fill with water the whole time.
    Apparently the insulation around the drainage pipe is too thin, causing the cold temperature to freeze the water.

    The drainage tube is about 8mm in diameter. So I was wondering....is it possible to build a small battery powered heater wire that can be placed inside the drainage tube to prevent the tube from freezing up?
  2. jcsd
  3. Jan 1, 2013 #2


    User Avatar

    Staff: Mentor

    Hi bosklong, http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

    Can you post a pic? While anything is possible, it's difficult to imagine that the manufacturer's testing would have missed such a glaring flaw. Some alternative fix may provide a better/permanent solution.

    Is this a new fridge, and still under warranty?
    Last edited by a moderator: May 6, 2017
  4. Jan 1, 2013 #3


    User Avatar
    Science Advisor

    You may have the freezer temperature too low or the airflow to the fridge too restricted (by the temperature control) so that cold air accumulates in the water reservoir.

    It is normal for some condensation to occur here, but the air coming from the freezer should not be cold enough to freeze the water before it flows down the tube.

    The water comes from frost which forms on the walls of the freezer but is melted periodically so that it does not need to be defrosted later.
    If it blocks, water can no longer flow down the the tube and it builds up in a little reservoir until it runs down the inside of the fridge at the back.

    Try increasing the temperature of the freezer. This will save you power and have no effect on the frozen food as long as the temperature is still -20°C (4°F) or lower. Ensure that the control for the fridge temperature (if it is a mechanical one) is at least halfway open.

    The tube can also get blocked with food scraps and then it needs to be cleaned with a pipe cleaner or similar.
  5. Jan 5, 2013 #4
    Heating with a battery is usually a bad idea, because heating uses a lot of power, and you would have to exchange the battery a lot. If the drainage hole is open on the other side, you could try to put in a copper wire, to transport a little more heat from the outside into that hole.
  6. Jan 15, 2013 #5
    Hi Guys,

    Sorry, I was away for a couple of days.
    Please find attached a picture as requested. The fridge is modern, but past its warantee, a with most electronics nowadays! There is definitely no food stuff falling down the drain pipe and the temerature is set correctly. I do however think that ventilation at the back of the fridge might be a cause to the problem as listed earlier by someone. Kitchen cupboards are built all around the fridge, preventing good ventilation. My dad has asked around and some of the local refrigeration companies reckon the insulation around the pipe in the back is not sufficient to prevent the drain pipe from cooling to such an level where it freezes the droplets. Naturally the more ice is present, the faster it freezes up.

    Attached Files:

  7. Jan 15, 2013 #6


    User Avatar
    Science Advisor
    Gold Member

    Have you checked to see if the fridge is level? Also, some fridges have a defrosting element in the freezer section and if it's defective......
  8. Jan 15, 2013 #7
    Have you tried to clean the tube really well - it is very easy to stuff to start growing in there, reducing the ease of flow.
  9. Jan 15, 2013 #8

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    What's behind those two screws?

    That looks like the defrost heater cover to me.
    Defrost heater comes on once a day to melt ice from the coils, and that looks like many days worth of ice...

    I would inspect the heater to make sure it's not got a melted spot anywhere.
    If it's not heating along its whole length it may not warm the drain tube during defrost cycle.
    They are usually "Calrod" heating elements, a black tube about diameter of a pencil.
    When they short out it makes a small crater where the case melts through and the remainder of its length makes no heat.. Sometimes a breaker trips and sometimes not, depending on where the fault occurs.

    Also, with that much ice - are you sure you don't have a leaking icemaker valve?

    You can probably find a parts diagram at the manufacturer's site - unless it's an LG brand.
    Sears has a pretty good portal into a large appliance industry parts database.

    good luck !
  10. Jan 15, 2013 #9


    User Avatar
    Science Advisor
    Gold Member

    [off-topic] You got that right. I have large capacity '76 model Kenmore washer & dryer that's had a couple parts ware out over the years. I can call them with the old part number and have a new one at my door the next day; and for cheap. [/end off-topic]
  11. Jan 15, 2013 #10


    User Avatar
    Science Advisor

    I've found the cheap bi-metal over-temp switch bad in several that I've fixed over the years. It's dies open so the heater coil never gets hot.

    Example switch: http://www.alibaba.com/product-gs/542665482/KSD_ST_001_N13_4_SAMSUNG.html
  12. Jan 17, 2013 #11
    I see that typed wrong in the beginning....Its not my fridge, but one at my folks's house. I will be visiting again within the week and follow up on some of your questions...

    The fridge is level, but I'm not sure about the defective element...will have to inspect.

    Yes, every time my dad defrost the chunk of ice he will brush the downpipe to make sure everything is clean.

    Un/fortunately there is no ice maker on the unit. I will note all the details,eg model number on my next visit.

    Thanks for all the help so far!
  13. Jan 17, 2013 #12


    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    This effect is not uncommon, I believe. I have found it in a 'frost-free' freezer and the only solution in that case was to let the whole machine defrost completely. Clearly, the 'has it defrosted?' sensor is not in the appropriate place and is too optimistic. But inside a freezer compartment, everything is well sub-zero and the defrost element has a hard job to do. You can tell if the defrost heater in the fridge compartment is actually working because the frost on the cooling plate should melt visibly and form drops which run down into the drip channel just before the compressor starts to run. A thin piece of wire, pushed down the whole length of drain tube should clear any obstruction that could be preventing water from clearing but if there's a plastic / rubber section in the pipe, it may have a kink which still interferes with the draining. The drip channel shouldn't ever get below 0C in a normal fridge compartment so any water in it should run away before the cooling starts again. Have you tried running the fridge at a slightly higher (temperature) setting? Could the fridge be over-full in that area and allowing the drip channel to get too cold by restricting air flow to the rest of the cabinet?
    Problem is that these things take a long time to sort out and you really need to be there over a longish period.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook