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  1. #51
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    Re: Dropped in it and trying t get it sorted



    He is fresh out of the technical school and trying hard to make a name for himself. He spent a lot of time chasing leaks and then trying to get things right for us. A really great find he was. Now it seems we have no more leaks in the system. The cap coil was exactly what you had recomended in your email. we did not try shortening it, which may have made a difference, as he was just so busy trying to find the other silly problems. Will try slowly upping the gas as you suggest and keep you posted.

    That could well have been us passing Phi Phi Don the other day if I remember we had the square sail out and were enjoying the peace of a run with it, or if it was the next day then it was topsails and all doing 8 knots close reaching on about 12 of wind. Yeppers it was the yard for us over the holidays but well worth it as we got so many things we wanted to do done. It is amazing we are at last getting the boat where we want her and seeing the end of the big projects. Sorry about the genset if we can help let me know.



  2. #52
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    Re: Dropped in it and trying t get it sorted

    Good day Chef,

    Just a quick question about the small chiller. It has been acting a bit funny since the boat yard and rather slow to cool down ( running a lot) the pressures he has it at are about 150 and 5 which I remember your telling me was too high. Do you happen to remember what those pressures should be?

  3. #53
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    Re: Dropped in it and trying t get it sorted

    I cant remember what the pressures were before but 150 over 5 is not out of line. It would be nice to see the Dx in the range of 140 to 155 and the Sx from 5 to 10. Ideal would be around 145 over 7 but that will depend on what temperature the box is and as its a chiller I am assuming the plate is at about -5C.

    As it has been regassed you should wait till its at steady state and then see where the frost extends to on the evaporator plate. It may go over the whole plate so place your hand on the entry to the evap and see how long it takes to remove the frost and do this in the middle and at the exit end. If the frost melts really quite quick at the exit end compared to the entrance end you may be short of gas a little. Difficult to give hard and fast guidelines on this method as it is system and hand specific. Let your hand warm up in between though or use it to keep your beer cold. As your techy said its very sensitve to just a small amount of gas and so try not to take the gauges on and off too often till it is about right as the gas from the system to fill the gauge lines will upset the system each time you connect them.

    As it is a built system you wont know what the critical charge is and so you cannot weigh in the gas but after a while you will be able to feel the lines at various places to give you a feeling of how it works, each of the 3 systems will be slightly different though.

    Did the strange vibration on the coil go away?

    Chef

  4. #54
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    Re: Dropped in it and trying t get it sorted

    Well has taken me days to get loged in again. Had it nailed at 145 / 7 for 2 days the plates get cold but do not freeze even with it running constantly. You should hear the complaints from my poor batteries....Today I dropped it to 135/6-5 will try and see if that is better. Since we know it works I am assuming it will just be a matter of mucking around slowly until I hit the right combination.... or not &)
    As to the coils they shut right up when the new ones went in so you must have been right about it going super sonic and creating shock waves. Slowly this is becoming a working system.....I hope!

  5. #55
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    Re: Dropped in it and trying t get it sorted

    Well it has taken a long time to get back in here but the report is good. After a lot of very careful whiffs at last the system settled down. I only get -11-12C on the small one, -7-8C on the large one and the chiller is doing just fine. We are thinking about making the boxes a bit smaller as Chef suggested. The idea is to fill the bottom with a few sheets of sealed cell Poly foam, just to reduce the space. The chiller is OK as it is. Any idas how much we should shoot for in the reduction? 2nd question there is a small possibility we can get 1 of the 90 bd compressors that would go on the large freezer. Would that make sense Chef and any ideas if it would be worth while? Thanks again for all your great help.

  6. #56
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    Dec 2009
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    Re: Dropped in it and trying t get it sorted

    Quote Originally Posted by H/V Vega View Post
    G'day,

    I am the skipper of a 120 year old Historical Vessel that keeps herself alive and sailing by delivering Medical teams and medical supplies to isolated Island communities. Many of these islands have not seen a nurse, much less a doctor for 20 years. We specialize in child immunization and general health as well as public health education. Why I am here is simple, well maybe for you lot, most of our medications require refrigeration. Some in fridges and others in freezers. When our old system started to die one of our sponsors was kind enough to send us a load of "just what you need" for a new installation. That is two freezers and a fridge. The second freezer is because everyone enjoys a cold one at the end of a long hot day, right? Also it is not really a good idea to do as we were doing and store medical supplies along side food.

    Well as the story unwinds we have three Danfoss DB50F compressors with the 12 VDC / 220 VAc electronics packages and a mountain of other bits and bobs. We had the new units made up to drawings with built in Eutectic plates. That took forever, isolated places are not known for harboring rocket scientists, filled them with the suggested mix and called in the local freezer man to install the lot. Well wonders the chiller works! The freezers how ever never freeze the plates and just will not get below 4-5 degrees C. From 27 G till 10 C they go down at about 2.5 degrees per hour then from 10C until about 5C it's 1 degree per hour. After that the whole thing stalls.

    The freezer man at first said we did not need the Danfoss TN2 valves and accumulators but insisted that a coil ( looking like a spring) of very small pipe was enough. HUmph! Well that doesn't work at all. Any one feel like being our "remote advisor? The guy is willing, but his experience is very limited... best I can say is he solders nicely and is very careful about insulation. I have a good technical background so if someone will explain what we should do I will guide this guy through it.

    Best regards

    Shane
    hi vega,i would first of all check the refrigerant charge then the electronic controls to see for any unwarranted shortcycles on the system.

  7. #57
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    Re: Dropped in it and trying t get it sorted

    Quote Originally Posted by H/V Vega View Post
    Well it has taken a long time to get back in here but the report is good. After a lot of very careful whiffs at last the system settled down. I only get -11-12C on the small one, -7-8C on the large one and the chiller is doing just fine. We are thinking about making the boxes a bit smaller as Chef suggested. The idea is to fill the bottom with a few sheets of sealed cell Poly foam, just to reduce the space. The chiller is OK as it is. Any idas how much we should shoot for in the reduction? 2nd question there is a small possibility we can get 1 of the 90 bd compressors that would go on the large freezer. Would that make sense Chef and any ideas if it would be worth while? Thanks again for all your great help.
    Missed your post earlier. There may a few things to try before you opt for a bigger BD90.

    First check all the seals to make sure you have no air leaking in and through the system, this is normally shown by a large and quick frosting of the plates with a quick build up of ice. If it lasts 2 weeks between de-icing it is OK otherwise you may need to focus on the door seals. Also de-icing weekly is a good procedure on these systems. Just remove the gear, point a spare fan into the box and it is done in 5 mins.

    Second you should check if you have a drain line from the box's, this is to help drain away liquid from the box (if you get any) but sometimes they just let cold air pour out and warm air creep in by the seals. Sometimes a loop in this vent line (in a warm area ie bilge) will trap some water and stop it from dumping cold - otherwise stick a plastic plug in it till you de-ice.

    Next try a sheet of say 1" non hygroscopic foam on the bottom of the freezer - a good fit is preferred but as you have SS solid interior the cold will still travel along the metalwork but worth a try as it is easy to do at no cost. Note the difference with the same goods loaded and then try 2", you will soon see if this going to work.

    Last try a top cover - keep your goods at least 3" below the underpart of the top of the freezer and then place a nicely cut to shape foam pad (again 1") on top of all the goods, this works quite well and may not get you much more cold but it will hold for longer.

    With all this done you may see a couple of degrees or more?

    As to putting in a BD90 - well that would have to be checked to see if it matches your evaporator, the condenser and you will need a new cap tube (thats a bugger) so it should be a last ditch attempt really.

    What RPM are you running the BD50 at? This could be important in future work?

    Best

    Chef

  8. #58
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    Re: Dropped in it and trying t get it sorted

    Hi Chef,

    Well thanks again for the wise assistance. Most of what you mention you had mentioned before so those are things already done ( we take your advice quite seriously) Will look for foam today to try filling the bottom up a bit. I think starting with 2" will not hurt at all as those two units are quite deep. Not much problem with frosting up. It is lasting several weeks more like a month between defrosting. A build up of about 1/2 " on the plates is when Meggi attacks it. Seals are good no signs of leaking there. We have the "top covers" in place and find them quite useful when taking things in and out to seal the top when they need to be open for a while, for what ever reason. The BD50's are set at about 3,250 according to the resistor values. That had more to do with available resistors than desires. I did replace the cooling fans with more powerful units and that seemed to help a little. Oh well the saga continues. Perhaps one year these things will settle down and I can put away the gas bottle and gages for a while. Thanks again for all the help.

  9. #59
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    Jun 2007
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    Re: Dropped in it and trying t get it sorted

    Can you see the resistors and if so what are the colour bands, worth checking this out first as again its an easy option.

    2" sounds fine and it will be interesting to see the results.

    Chef

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