3/3/2014 – Fridge update

Spent almost all day futzing with the fridge.  I think I know what’s going on but not quite sure how to go about fixing it.  The Frigoboat reefer is a capillary tube system.  That means that refrigerant is pumped by the compressor through a teensy little tube (the capillary tube) putting it under very high pressure.  When it reaches the evaporator plate inside the fridge, the tube suddenly gets bigger.  The drop in pressure allows the refrigerant to boil.  The refrigerant (freon or whatever they use now) boils at a very low temperature but it still takes heat to make it boil.  The heat, in this case, is supplied by the ambient air inside the fridge box.  Boiling the refrigerant pulls heat out of the box, thus lowering the box’s temperature.  Or at least that’s how I understand the process. Anyhoo, the spot where the capillary tube meets the bigger tube, at the evaporator plate, is a spot where oil, water or dirt can cause an interruption in the flow of refrigerant.  No flow, no cooling.  And that’s where we seem to be.

How did I come to that conclusion?  Well, when the refrigerant is flowing, you can hear it.  It’s quiet but if you listen close you can hear the gurgling of moving liquid.  However, we haven’t been hearing that lately.  Today, I happened to bump the capillary tube where it makes the transition to the big tube and suddenly I heard the gurgling sound and immediately the evaporator plate started to cool down.  After a couple minutes, the gurgling diminished and then stopped altogether and the frost on the plate melted.

I’m pretty sure that dirt isn’t the issue as it doesn’t fit in with the symptoms in the book.  Dirt would plug the other end of the capillary tube, not the place where it suddenly gets bigger.  That leaves either oil or water. The book says that the only way water would get in would be through faulty service or a leak.  Pretty sure we don’t have a leak and the system hasn’t been opened since I first installed it back in 2009.  Oil, on the other hand, sounds like a likely option.  Apparently there’s a little bit of oil in the refrigerant but it should pump through the system just fine.  However, to quote the manual:

This is most likely to occur in freezer systems that have seen continuous or near continuous trouble-free operation for

several years and either; (a) after the evaporator is defrosted with a high temperature heat source (hair drier, heat

gun), or (b) after the vessel has been left unattended and closed up in a hot environment.

 

Other than the fact that ours is not a “freezer system”, (b) pretty much matches our situation.  So, what to do?  Well, the book says to apply heat to the capillary tube in the form of a hot, wet cloth.  This is supposed to expand the tube and lower the viscosity of the oil, allowing it to flow more freely.  So, I tried it.  Boiled some water, wet a cloth with the hot water and, with tongs, held it to the cap tube for a couple minutes.  And you know what?  It worked.  For a few minutes.  Then the flow stopped and the plate thawed.  The book says you may have to do this a number of times before the situation returns to normal.  So, all afternoon, Lulu and I applied hot wet cloths with varying levels of success.  Sometimes it worked for a minute or two, sometimes for several minutes.  Finally I decided to screw the wet cloth. Let’s get serious.  We filled a shot glass with boiling water and dipped the cap tube in it for a couple minutes.  I’ll show you tube expansion!  I got your viscosity-lowering right here!  And it worked!  This time it worked for quite awhile, maybe twenty minutes or so.  We thought we had it dicked until it suddenly quit again.

Throwing in the towel for today, we loaded the fridge with ice, turned the compressor off and will try again tomorrow.  Maybe, by leaving it overnight, it will miraculously heal itself.  Could happen.  Right?

Oh, and by the way, the fridge was left on the whole time we were gone (3 months).  It must have worked OK until just before we got here because the beer was still very cold but Lulu said the plate looked like it had been defrosted.

So, my two big challenges for tomorrow: make the fridge work right and try to stow all our crap without resorting to stowing it on the cabintop again.  The cabintop looks so nice right now without a bunch of stuff on it and I’d really like to keep it that way so I’m going to have to do some creative thinking to come up with alternative stowing.

 

PS: for those who think we need more refrigerant, the test is supposed to be: if the plate ices over completely and evenly and the return tube doesn’t ice up at all, the refrigerant is right.  Well, when things are flowing, that’s exactly our situation so I doubt refrigerant is the problem.

 

to be continued….

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About sryoder

Steve & Lulu... retired. Had enough of the cold wet dreary fall/winter/spring in the Pacific Northwest. Bought a boat, fixed it up, sold our home and sailed to Mexico in November, 2010. Been here ever since except for occasional forays to the States (summer only, thank you) to visit the kids, parents and siblings. If you're looking for a sailing blog, this is the wrong place. This is a traveling, hunkering in, eating blog. Sailing is just how we get from place to place when we can't walk.
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10 Responses to 3/3/2014 – Fridge update

  1. Jacaranda says:

    Just curious why you would leave a piece of gear(like a fridge) running for 3 months while you were gone?

  2. sryoder says:

    Two reasons: 1.) My experience is that machinery that is used seems to continue to work better than machinery that’s left idle for long periods, and 2.) We had bad results when we left everything off (by necessity – we were in the storage yard) in San Carlos one year. The insides of the fridge bulged inward, probably as a result of moisture in the surrounding insulation expanding from the heat. Granted, it was summer and much hotter than it was likely to get in La Paz while we were gone but still chose not to take a chance. We’ve left it on before when going back to the US for months at a time, most recently this last summer when it ran w/o us for 2-3 months at Costa Baja where the weather got very hot. First time we’ve ever had a problem.

  3. vraymond108 says:

    Steve
    You are more patient than I. I would have resigned long ago and called in a refrigeration guy. Those systems are so common place that someone in that cruising Mecca has got to know how to fix it. I will have to download the manual though as seems to have plenty of good advice.
    Good luck today with it.

    • sryoder says:

      I want to be able to fix anything on my boat no matter where we are. This is my first exposure to fridge repairs as the Frigoboat system has worked absolutely flawlessly up until now. I may end up having to call in the big guns but not until I’ve exhausted everything I can possibly do myself.

      There’s the manual and then there are also a bunch of other files with info. It’s all right here.

      • vraymond108 says:

        Steve, while I agree about knowing how to fix anything, what I TRY to do is fix it myself. Then if that does not work get in the the BIG guns, as you say. But I stay with them and watch everything move so I can learn what they did. Of course it doesn’t always work since they sometimes have some fancy equipment that I don’t or won’t have but you the idea.
        Refrigeration is one of those areas that I know little about and am impressed with how well you are versed in the subject. In fact your explanation above is the first time I actually understood how it works.
        In Curacao we ditched our perfectly good water cooled cold plate system for the simpler Frigoboat/Danfoss compressor and evaporative plate. Now I don’t have the run the generator for about an hour a day just to cool the refer. The solar panels alone supply enough juice for the refer system plus lights etc. I probably threw out out a $6,000 plus system but simplicity is the name of the game for us. Probably you too. Of course that block of ice is probably the easiest way to go if you can get it in blocks and not a bag of cubes.
        Hoping your mystery is solved soon.

      • sryoder says:

        I’m not completely averse to calling in the pros when necessary as I did in San Carlos a year ago November when I could not get my engine to start no matter what I tried. You can bet I watched and wrote down everything Omar the Mechanic did. I’ve added what he did to the manual’s troubleshooting guide.

        We chose the Frigoboat (keel-cooled) primarily for it’s efficiency in converting precious amps to btus. The fact that it was more or less modular helped as well. Haven’t been disappointed yet. I didn’t know anything about refrigeration either until I started investigating the problems here. Well, I knew a little bit but not much really. Still learning, too. BTW, our fingers are crossed but we may have gotten the fridge straightened out. Filled the fridge with ice last night and shut the system off. Let it sit overnight and started it back up this morning. It’s now been operating correctly for well over an hour so we’re very encouraged. Shutting it off to let internal pressures drop enough to allow any obstruction to relocate is actually one of the book’s solutions. Maybe we just hadn’t turned it off long enough before. They don’t really address how long is long enough. Keep your fingers crossed for us.

  4. vraymond108 says:

    Fingers are crossed and I will try to remember that tip too.

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