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Post by schocktherapy on Sept 20, 2011 19:08:41 GMT
Well, i honestly have no idea how much a replacement evaporator assembly costs from frigoboat. I have never bought their products, and based on what I've read on this thread I probably never will! Clearly they have serious quality control issues. If debris in the evap assy is a known problem, who is to say the new one isnt going to have the same problem?
As for making my living, it has been many years since I have relied on the marine refrigeration industry for my living. I used to install custom refrigeration systems based on NovaKool components for the local Hunter broker, as well as a number of other brokers and individual boat owners. These days I only work on boat systems for friends and fellow yacht club members. The fact of the matter is, there are too many unqualified guys out there installing kit systems for far less than I am willing to work for. My time is billed out at $110 per hour these days and i have as muchwork as I want. The problem is, sailors are notoriously cheap! Comments like "the wind is free so they think everything else should be too" are all to common in the industry. I have friends who are riggers, sailmakers and boat repair experts, and none of them are getting rich I can assure you.It doesnt surprise me that people have a hard time finding good refrigeration guys to work on their boats; the good guys are going to go where they can make real money!
So you see I have no vested interest in advising people to use professionals, I am just trying to help my fellow sailors understand the systems on their boats, and the pitfalls of DIY in some instances.I am offering advice based on 20years as a refrigeration technician, and it is free. Do with it what you will!
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Post by kollmann on Sept 20, 2011 20:37:18 GMT
ANSWER:
Boaters are forced to be Do It Yourself mechanics for many reasons and need practical advice. In most refrigerator repairs mistakes can be avoided with simple steps without expensive technical services. The repair plan I recommended required only basic available tools with the exception of a refrigeration vacuum pump. These pumps can be rented at tool rental places or barrowed from a fellow boater. If you review my six books on boat refrigeration and my web forum you will see I only recommend using a service technician when required. I also never recommend using solder to connect lines without proper protection, flow tests and use of nitrogen gas to prevent interior line oxidation from heat. Again if you read through my forum you will see many refrigerant flow problems caused by poorly soldered connections.
As to Schocktherapy’s question, What exactly do they mean by "dehydrate the system for several hours at 100 degrees"?
Pure refrigerant is the key to a refrigeration unit’s life span and every effort needs to be made to keep moisture out of refrigerant. Job shops that build these systems do not always remove all moisture and moist air will be induced any time a refrigerant line is opened to the air. In the past it was easy to remove moisture from refrigerant and Mineral oil. On a 70 degree day with old systems moisture could vaporize when system pressure was reduced to below 700 microns vacuum, allowing vacuum pump to remove moisture in one hour. The new generation of refrigerant 134a and Ester oil resists the phase change of water droplets in oil needed to convert water to gas that could be evacuated by pump.
If moisture is to be dehydrated from these new systems either a deeper vacuum is required or temperature of complete system needs to be increased, The higher system temperature is the easier it is to boil moisture at below atmospheric pressure. My tests show that using a hair dryer to heat compressor and evaporator to no higher than100 degrees F while vacuum pump is running for four hours will dehydrate these small systems. If you call a service man he will recommend a new system after he makes two trips attempting to correct moisture problem and fails. Smart Service techs carry a micron meter and will leave pump running until vacuum is below 300 micron, this might take 24 hours in cool climates.
For someone who never charged over $20 an hour for boat refrigeration work over the last 25 years I have no comment on $110 per hour.
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Post by schocktherapy on Sept 21, 2011 3:43:03 GMT
Well Kollmann, first of all I have had a look at your blog, and it has lots of good information. You are certainly providing a service to boat owners by providing that resource. Obviously I can't comment on the DIY books that you are selling on the site because I haven't seen them, but I am sure they help the average boat owner to understand their systems better.
You seemed to sneer a bit when you commented on my company's hourly rate, so let me clarify a bit. I am a licenced journeyman Refrigeration/HVAC technician. I also hold an Electrical ticket and a class B gasfitter ticket. I work on everything from the simple little systems we are talking about here up to 100ton blast freezers, refrigerated warehouses big enough to hold the boats of everyone involved in this thread at once. (without masts of course!) I have extensive experience with ice makers of all types up to and including industrial flakers used in the fish packing plants. I also service and maintain building automation systems and all the associated chiller plants, cooling towers, heat pumps and air handling systems that keep office buildings comfortable. I also install and service commercial food store refrigeration systems. The list goes on.
So you will forgive me if I chuckle a bit when you refer to these basic little refrigeration systems "new" and "modern"! Sure, Danfoss has come up with some nice little variable speed compressors, but seriously, there is nothing new about Polyol Ester oil and R-134a! They have been widely used for over 20 years! (in fact r134a is destined to be phased out soon.) Cap tubes and evaporator plates? That is the exact same technology you will find in 1940s vintage domestic refrigerators!
Now, regarding vacuum pumps removing moisture: yes it is true that POE oil has a high affinity for moisture, heating up a system can't hurt. That is why I use a hot nitrogen purge when I suspect alot of moisture. (I have had systems literally flooded with water after a water cooled condenser failure and managed to eliminate the moisture using this technique among others) However, when we are dealing with trace moisture a vacuum pump with FRESH oil in it will easily deal with it at any normal ambient temperature. The reason for this is because water cannot exist in liquid form. Everyone knows water boils at 100 deg C (212 deg F) at atmospheric pressure, but if you can achieve 4000 microns the boiling point of that water will be below 32 deg F. As Kollman said, ideally your goal should be 700 microns. The reason you need fresh vacuum pump oil is because vacuum pump oil has an even higher affinity for moisture than POE oil, so it will become saturated with moisture with use. (even an opened container of oil is questionable for our purposes.) If the oil is saturated it will not allow the pump to achieve the deep vacuum required. Now I have never seen a vacuum pump at a tool rental shop, although to be fair I have never looked for one. If you do find one you can be sure that it has been used for everything but refrigeration. Most likely people would use it for vacuum bagging their fiberglass projects. So if you do find one to rent, make sure that you buy a fresh, sealed bottle of actual vacuum pump oil, and change the oil just before you are about to use it.
When it comes to how you make the connections, the industry standard for copper joints is silphos brazing not soldering. It is much more tolerant to temperature changes, more resistant to corrosion and can withstand higher pressures. It is true that the best way to braze or solder is to have an inert gas, usually nitrogen, in the system to prevent oxidation inside the pipes, which can come loose and circulate through the system. Having said that, a good filter drier will easily handle that tiny amount of debris. (Modern refrigerants such as R410a are much less forgiving, and nitrogen is a must!)
One last note: if you follow correct refrigeration system design, a filter/drier is not an optional component it is a must! Good practice also demands that you replace the filter drier every time you open a system up.
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Post by kollmann on Sept 21, 2011 14:23:41 GMT
Now schocktherapy, that we have side tracked this thread about what to do with a temporarily blocked cap tube on a variable speed Danfoss 12 volt refrigeration system, What do you recommend as a permanent fix? These are the options you and I recommended:
• Contact Frigoboat US the experts in this country about the parts replacement they have recommended in the past as a final. Fix, Larger filter/dryer with quick connecters installed, new evaporator assemble with line connectors and O ring kits for line connecters on condensing unit. This would mean owner or a helper with standard hand tools to replace evaporator assembly and connect in new filter assembly. The only jobs left are leak testing dehydrating, and servicing with refrigerant. • Schocktherapy, when I am doing significant repairs to a kit system I don't replace the o-rings in the quick couplers, I cut the couplers out completely and braze the pipes directly. The couplers are a common leak point and are completely un necessary. If there is a lot of excess lineset coiled up I will also cut out the excess pipe. (Some manufacturers run the capillary tube inside the suction line which complicates things a bit but it still isn't hard to do.) • Suggest boater in trouble with this system buy a new complete system. • If refrigeration is not important tap on line to dislodge item away from capillary tube inlet when blockage occurs again.
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Post by schocktherapy on Sept 21, 2011 16:02:32 GMT
The main area where our opinions diverge is the idea that you must replace the complete evaporator and lineset to solve the problem. I don't know how much Frigoboat charges for their evap assemblies, but I am sure it is not cheap. One would have to weigh that cost against how much a fully equipped refrigeration mechanic would charge to actually repair the system, and make sure the refrigerant charge is correct. Using pressure guages on a system is NOT "destructive testing", although careless use can introduce contaminants. Refrigeration is all about temperature/pressure relationships, and it makes no sense not to have all of the information.
I certainly don't agree with the statement that someone having trouble with their system should just buy a new one! My whole point here is that this is not a difficult problem to solve if you are armed with the right knowledge and tools. The only time i would advise replacing an entire system is if the compressor itself had failed. Everything else can be fixed.
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Post by kollmann on Sept 21, 2011 19:41:30 GMT
I will make it easy for you to answer the question. A technically inclined boater can complete this project for under $500 by bolting on off the shelf hardware. The method you described would cost from $800 to $2000 to guarantee completion if charges include tech persons travel time. A new system could be installed by owner captain for around $1300.
Yes, you could say you could re-commission this system for less than $500 but it is unlikely a person with your experience can be found where this boat is located.
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Post by schocktherapy on Sept 21, 2011 20:14:44 GMT
Really? $800 to $2000 to repair the system? I don't think so. The procedure i described could be done in 4 hours. Even if somebody took all day and charged $50 per hour, you are still only looking at $400 in labor.
Whatever.
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Post by sirromcd on Feb 12, 2012 0:24:37 GMT
::)Good morning, This is the text of the message sent to Figoboat's technical help yeasterday before I found this string. We are currently at Miri Marina in Borneo, an area remote from technically competant refrigeration techs... Our 10 Y/O AH 35 F Frigoboat refirg unit has just started to function erratically. We have an aluminium evaporator plate (260mm x 900mm) bent at right angles mounted at the top of the frig box. We usually run the thermostat on 5 or just a smigin over and the evaporator is usually 3/4 covered in frost. In the past week the frost has been melting from the outer end of the evaporator and is now only immediately around the entry from the compressor. We called a local frig mechanic who checked the gas level, which he found OK but was at a loss to explain and why the evaporator has started to perspire rather than freeze. He suggested the compressor was too hot an possible needed replacement. The compressor temp was about 48 deg C. We read in the paperwork where the condenser temp was 54 deg C. We have looked thru the Trouble Shooting chapter in the manual and not found an obvious solution. We have checked the thermostat connections and all the electrical connections but cannot find a problem. There is no red flashing LED. Help Please Now I have read the forum I will implement the suggestions associated with removing small particles or water from the cap tube entering the evaporator, using the tapping or heating method, and replacing the o rings in the couplings. I will eventually remove the gas and water vapour using a vacuum pump and replenish the refrigerant gas. Does anyone have any additional suggestions? Not serious Doo Doo but the wafe's cranky Sirromcd
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Post by sirromcd on Feb 12, 2012 4:34:37 GMT
More on the above. I turned off the frig and let it warm up for 12 hours then tapped the cap tube and restarted the frig. Immediate sound of trickling rather than gas his came form evaporator. Temp at the cap tube entry dropped immediately to form an ice rind, then just a quickly went away. tricking sound still evident and temp at entry of cap tube is 18 deg C. Now what? Comp temp still ok at 41 deg C and delivery pipe not hot (31 deg C) but return pipe cooler. Thinking now I have a water blockage in the cap tube and to apply heat to evaporator at cap tube entry to melt and see what happens. Here goes. Sirromcd
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Post by sailbleu on Feb 12, 2012 7:14:01 GMT
Please keep us informed. I guess at this stage nobody will be able to help you,... sofar that is. More info , experiments and results are needed. But if your unit is the same as described as above , you can bet your bottom dollar it's debri thats blocking the cap tube. By the way , I still have my problem you know , I really look up (read resent) to the idea of breaking out and replacing the whole lot.
Regards
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stack
Junior Member
Posts: 24
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Post by stack on Feb 12, 2012 22:25:13 GMT
Check the thermostat. These controls don,t last forever. Joe
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Post by kollmann on Feb 13, 2012 18:44:51 GMT
Chris, Gurgling sound confirms gas and oil is moving so there is no blockage.
No frost on evaporator, amperage below 1.5 amps, and gas moving through system indicates lack of refrigerant.
These are the steps needed to re-commission your system:
1. Check gauge set to see that gauges read zero if not adjust or make a note of their errors. 2. With both gauge hand valves closed connect 134a bottle to center yellow hose. Check to see that blue gauge has blue hose and lose end of blue hose has a valve core depressor inside. Before connecting blue hose to low pressure connection open blue gauge valve for 2 seconds to purge yellow and blue hose then close valve and connect blue hose to service fitting on top of compressor. 3. Inspect valve cap you removes to see that rubber seal inside cap is still good. Slow leaks are sometimes traced to a bad cap seal. 4. The blue gauge should now be reading system pressure of 30 to 60 psi depending on temperature of complete system if unit has correct refrigerant charge. 5. After blue gauge is connected you will need a one inch paint brush and a small amount of water and liquid dishwashing soap mixed 50/50% to locate refrigerant leak. 6. From the performance indications above I would guess gauge pressure is less than 20 psi. so we need to add refrigerant and then leak test system. Open blue valve and allow refrigerant gas to enter system. Refrigerant bottle needs to be in upright position to add gas vapor only. Stop adding refrigerant when blue gauge reads 50 psi. 7. The slow loss of refrigerant is on that unit is at one of these points service fitting cap seals, O ring seals in one of the two metal line connectors or a micro hole corroded through aluminum evaporator plate. 8. With 50 psi of gas pressure in system use soap and water mixture to locate leak. By using brush to apply mixture to only one point at a time stabbing brush into location until a shaving cream mixture surrounds it you will break down to liquid surface tension so any leak must come through foam generating bubbles. Leak testing is done with compressor off. 9. After leak is found and repaired unit can be serviced with correct amount of refrigerant. In your situation best way to get correct charge is again raise pressure 50 psi then run compressor for 10 minutes and then and only then adding refrigerant if necessary or reach 6 to 8 psi suction pressure. It is important that you not add refrigerant after 20 minutes run time as correct pressure can not be determined after 20 minutes. For final fine tuning unit needs to run for a day or more. Correct refrigerant charge for your unit is when 90 to 100% of evaporators surface is covered with frost and no frost on line outside refrigerator on line returning to compressor.
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Post by sailbleu on Mar 16, 2012 6:42:15 GMT
I'm back ! First of all I would like to apoligize , I might be sounding like an old drag now , but my fridge is really driving me up to the wall. I will fill you in on the new episode , a supprising one , again. No doubt most of you have followed this topic from the start , in particular the experts who have been providing us with valuable information. After all , I guess the major part of boat owners will sooner or later be confronted with a grumpy fridge. Mine is been giving me an emotional rollercoaster for some time now. I hear you think , get in a technician. No problem , but first of all try and get one prepared to come over for such a tiny job. And second , he will have to start his quest by observing the sings , the malfunction , the symptoms in other words. That's the part where it goes wrong all the time. I have switched one my fridge more than ones this past winter , looking for a pattern. The only pattern i've been able to find is that there is no pattern what soever. -Sometimes the fridge starts up and keeps on running for days. That means there is no prob with the amount of refrigirant . Right ?? -Sometimes the compressor starts up , and no evaporator cooling occurs. That could point out to an obstruction in the capilar tube , which seems to be a common error (according to Richard Kollman) for this type of fridge. Tapping the capilar sometimes (infact most of the time) revived the fridge and the cooling proces restarted . During my last trips the fridge was running for weeks and suddenly rerfused any co-operation. After switching it off and waiting for a few days it restarted without any fuzz. To lay down its armes after a while ....again. That is been going on for much too long now. Again , get in a technician. Yes , sure , but what can he/she do - besides checking the refrigirant pressure - when the irritating bugger is performing flawlessly at the moment. A pressure that will more than likely be ok since the fridge can (sometimes) be working for weeks on a row. It's like getting a TV technician in for a TVset that has a malfunction , and when he/she arrives , the TVset acts like nothing ever happened. I would like to spare myself that frustration by getting in a frigoboat technician , paying his time for checking the pressure and having to hear him/her say that i would be better off replacing the whole lot. Thanks but no thanks. So a few days ago I decided to stop complaining , stop feeling sorry for myself and start rolling up my sleeves. After reading everything (more than ones) said by the experts on this board I was pretty sure a capilar blockage was haunting me. That meant getting the evaporator out . Easier said than done. I had to break down the oven so I could slide the tubes through the sidewhole in the fridge , after decoupling the compressor of course. While I was at it , I thought ......why dont I just try the fridge again . See it as a last attempt for a final diagnosis. So the switch went on , the evaporator hissing started and everything was cooling down. Suddenly the hissing stopped , the compressor was still running . No led was blinking , it never did by the way . Now that gentlemen , after reading all the advise given in this topic , could be a sign that moisture was blocking the capilar. Right ?? Therefor I got in the heavy artillery. A grown up heater that would warm up the evaporator and also melt the frozen moisture inside. In the meantime the compressor was still running you know. And guess what ? Suddenly the hissing re commenced , without any tapping. After all the previous tapping on a warm evaporator and noticing the fridge come trough thanks to that tapping , It could be the distinct indication that moisture was the culprit. Well ,.... I just dont buy that. I placed all my eggs in the capilar debri blockage , and I dont intend to deviate. Therefor I would like the ask the experts a final question before I rip out the evaporator . Could it be that due to (excessive) heating - and expanding as a consequence - of the evaporator (and capilar) small debri could change place so the refrigirant has a clear pass again ? Mind you , this is the first time I heated up the evaporator with a heatsource. It never got this warm. Here's my plan of attack. If I'm right , and it is debri , I could flush the evaporator system (after getting it out) with filtered air , like in a backflow. Hoping to get rid of the small debri. Afterwards flushing and filling it up with refrigirant and reconnect it to the compressor again. Would that be a good idea ? Many thanks for your thoughts. Kind regards
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byo
Junior Member
Sun Oddessey 43 Deck Saloon, Yvonne (captain) and Bruce. boat name Blue Heaven
Posts: 20
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Post by byo on Mar 17, 2012 11:14:48 GMT
I have found the system to be good and unlikely to have lost gas as the compressor will not start at all, I think the problem is likely to be a faulty condenser fan, I had the same problem with mine, the fan worked sometimes but only weakly, other times not at all. The Frigoboat replacement is expensive but you can get the same unit from a computer or electronic supply shop for about $24-00 Australian and easy to instal'Cheers, Bruce.
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Post by sailbleu on Mar 17, 2012 12:53:29 GMT
Hi Bruce,
well , I can/could only hope(d) my problem was similar to yours. But it aint. The malfunction in your fridge is well documented on the previous pages. I'm not sure if you read all the postings , but I have also installed a led so any error would be indicated.Going from low voltage , to a bad fan. I advise you to do the same , it's easy. My led never gave a blink , not even when the fridge was behaving badly (read not cooling). Except on one occasion when the battery was low , the led told me that without hesitation , proving that the warning system works.
In my case everything was pointing to capilar debri since everytime I could eventually have the fridge cool again by taping the evaporator. This time the bastard rocked my world , but you already know the story.
It's waiting for Kollman and/or schocktherapy to get me out of my misery.
Regards
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Post by kollmann on Mar 17, 2012 18:24:44 GMT
After 5 pages of posts let us look at what is known and not known.
Compressor will run continuously sometimes cooling and frosting evaporator and then evaporator warms up. The troubleshooting LED does not flash and compressor keeps running this then confirms poor to no cooling is not detected by the electronic control module’s micro processor not sensing low voltage or high fan amperage or high compressor amperage What is confirmed is compressor continuing to run without cooling Question is there a low refrigerant problem or a refrigerant flow problem? At this point in troubleshooting it can be confirmed that intermittent refrigerant flow blockage must be occurring. There are only two major restrictions in this system where blockage can occur at the very long flow regulating capillary tube orifice or in filter dryer.
There are a number of items or conditions that can restrict and block capillary tubes. • Excessive moisture in refrigerant that can not be captured and retained forever inside filter/dryer. If one drop of water passes through dryer and inters cap tube its speed will accelerate and its temperature drops below freezing as it moves through the 9 to 12 foot long small orifice tube. Moisture/ice blockage restricting or blocking refrigerant flow is easily determined by looking for frost in spots where it should not be, like frost on filter or line connector. When moisture freezes inside cap tube sub cooled liquid refrigerant will be backed up into condenser causing compressor amperage to decrease and refrigerant low pressure to descend into a deep vacuum. The easiest way to determine that moisture/ice is causing refrigerant flow blockage is to monitor refrigerant flow sounds inside box near evaporator. When refrigerant is flowing normally spraying refrigerant into evaporator can be heard. If compressor is stopped when evaporator cooling stops and you listen for a while inside box ice blockage will melt and a bump will be heard along with a few seconds of refrigerant flowing into evaporator. • You are lucky your unit is air cooled with filter dryer in liquid line after condenser protecting solid partials from reaching cap tube orifice. Frigoboat’s keel cooler units do not protect capillary tube orifice with a filter in liquid side of their systems. With the exception of these keel cooler models capillary tube blockage on Danfoss small BD systems is vary rare and when blocked with solid material it is almost impossible to unclog the tube. • Sludge formation a mixture of water, refrigerant, and oil, can becoming acid sludge causing higher than normal amp draw and maybe restrict flow through cap tube. I have found where this acid sludge has eaten away aluminum from the inner layer or evaporator. This milky substance finally blocked capillary tube solid.
At this point I have not seen anything in this thread that convinces me moisture in system is not your problem. I think the next step should be to rule out moisture/ice: 1. Warm up box and evaporator temperatures to 90 to 100 degree F. I use on my test stand a 110 volt trouble light with a 40 watt bulb to maintain box and evaporator temperature higher than normal. The heat from light bulb must be positioned so it can not damage box or evaporator. With box lid or door open and evaporator temperature elevated turn unit on. Let unit run for one or two hours. If evaporator remains cold for two hours it sounds like moisture in refrigerant is likely. 2. Get a set of refrigerant gauges and before connecting them see that they both read zero and both gauge valves are closed. Check gauges before starting compressor both hand valves on gauge set will always remain closed on this test. Connect blue low pressure gauge to service fitting on dome of compressor and red gauge to service fitting on top of filter. Normally at this point gauge hose set would be purged with fresh refrigerant but in this case we know that refrigerant will be removed to make final repair. Last test will be to allow system and box temperature to reach cabin ambient temperature and close box without added heat from light bulb. Both gauges should read almost the same pressure and then turn compressor on. Now system is back to normal operating condition low pressure gauge will drop to maybe zero and reach 6 to 10 psi in ten minutes. Record low and high pressure at 10 minutes and again every 10 minutes. If and when low pressure drops to below 3 psi would be a sign of refrigerant blockage unless evaporator is extremely cold or high pressure is low. If total blockage occurs low pressure will drop to a deep vacuum say 20 inches turn unit off. If there is blockage watch low pressure gauge to determine rate of change. If mechanical blockage return to equal gauges pressures will be very slow. If ice blockage, pressure will hold until ice melts then start increasing pressure.
If moisture is confirmed an extensive dehydration process is required.
If solid material is indicated restricting flow replace filter/dryer and complete evaporator assembly followed by vacuum pump dehydration and re-servicing with correct refrigerant.
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Post by sailbleu on Mar 18, 2012 10:35:05 GMT
Hello Richard ,
thanks again for sharing your expertise. And as always , answers raise more questions :-) I can understand this must be your so maniest (is that a correct english word ?) time you respond to fridge problems , and I really do appreciate you willing to spent the time and effort to react. I'm not trying to flatter you in any way , I also have some things I know more about than some people and seeing the same questions return on a board time after time tends to make you indifferent after awhile. So again , I realize what you and others are doing here , thank you.
OK , back to the core of the case. It supprises me that you stick to the theory that moisture could be the culprit. I would tend to believe that tapping the evaporator when its warm or cold in order to revive the fridge would be a clear indication of debri , atleast that is what I understood of previous answers. Again I must stress out that the unit has never been opened or tampered with in any way . All the caps and connections always remained sealed.
I was hoping you could enlighten me with your thoughts on my theory about the evaporator expanding due to external heating up so small debri could pass through. Infact , could it be that the filter/dryer is disintegrating and occasionally leaks debri to the capilar tube ?
I will post another picture documented article tomorrow with pics of my gauge set so I can perform the test you suggested. I seem to be having probs with the proper connections since this is a set I use for car airco onces in a while , maybe you could guide me trought it. I guess that article tomorrow will be the last one before I rip out the complete unit and experiment with it in my garage. Or maybe I just bring it to a tecnician , have him replace the filter/dryer , vacuum the the lot and refilling the unit. I'm somewhat hesitant to renew the evaporator you see.
So Richard , please bare with me this last time , I also need to know how to disconnect the couplings to separate the evaporator and the compressor. I will get back to you tomorrow .
Kind regards
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Post by kollmann on Mar 18, 2012 15:40:46 GMT
sailbleu, Before the internet means of communications I spent over 40 years troubleshooting mechanical problems over the telephone. In the last 20 years with the internet troubleshooting directed to distant locations is more accurate in that it provides a step by step record on computer data. My boat refrigeration library now contains somewhere between 5,000 and 20,000 items from email and my forum. There are two important lessons I have learned in my 78 years with regard to troubleshooting; Confine troubleshooting first to non destructive testing and second troubleshooting must be a process of systematic elimination avoiding guess work.
Experience shows these small systems are simple enough for a boat captain to diagnose and repair most faulty conditions, with the one exception of refrigerant flow. If my last post is correct you must confirm restricted refrigerant flow is mechanical or moisture in refrigerant. If mechanical it can be caused by a number of things from desiccate crystals that came out of filter and moved down stream to capillary tube, or O ring material from line connector, to dried flux from one of the solder connections. If this blockage is mechanical the attempt to correct it without replacing filter and evaporator is a waste of time and money. If there is moisture in this system your question of how did it get there as it is an air cooled unit and no keel cooler? Who knows but you have not tested to eliminate it. With evidence of a sloppy solder joint on high pressure line coming out of compressor I can’t believe that was done at the factory. I included high pressure gas reading in test to eliminate read valve problem that might stop refrigerant flow by reduced head pressure to cap tube.
If you were to bring in a qualified service technician I think he is going to recommend a complete system replacement as there is no warranty that spending $400 to $600 US will solve this problem if it is caused by a thick liquid like sludge or liquid aluminum particles in solution.
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Post by sailbleu on Mar 19, 2012 9:29:01 GMT
Hello Richard, as promised , back with all sorts of pics and questions of course. Here's a pic of the compressor and the filter/dryer , as you well know. If I replace this , does it matter what kind of filter I use ? Meaning , after cutting (or welding ??) it out , do I just go to a shop and ask them for a similar one ? Next pic is the connections Do I just turn the indicated sides (red and black arrow) to the opposite side to release the coupling ? Here's some info on my equipment. And here is where it goes wrong , I dont seem to be able to connect the hoses to the connections on the unit. This gauge set is for car airco , and fridge connections are apparantly different. Can I buy the proper connections in a store that sells refrigiration stuff. Or is there and ebay site somewhere ? MAJOR EDITI have solved the issue of the connections. I have a vacuumpump by the way. I have welding gear (oxigen- , gastank and so on) I know what you're thinking , this guy has never worked on a fridge unit and he will try to service his boat unit. Well , I like a challenge once and awhile you see . And said in all modesty , without showing off mind you , I often succeed in the endeavour. So why not this time. After disconnecting the evaporator I could flush it with a solvent like aceton or similar to clean the system. Then dry it (airflow through it) while warming it up , flush it with R134a refrigirant , replace the Orings , vacuum the lot and refill the unit. But if I vacuum the complete unit , would I also need to inject new oil , or does the old oil remain in the compressor even when everything is being vacuumed Any idea on the total amount of refrigerant for this unit ?? There is an alternative tough.Would it be possible to install a supplementary filter/dryer in the high pressure circuit so any debri coming from the old filter (or drifting moisture for that matter) would be captured ? I could set up something between the high pressure connection you know. Thanks and kind regards
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Post by gene on Mar 19, 2012 23:19:16 GMT
I have similar problem. I have determined the problem is dirt in the evaporator tube and plan on changing it out and installing a new filter. In the meantime I have managed to get it working reliably by getting the dirt away from the orifice. This process went like this: 1. Let the system equalize, if it is plugged you will need to leave it off for a long time, perhaps 6 hours or more 2. Unbolt the evaporator, pull it out and tilt it up and sideways a bit till the orifice opening is pointing down. I have a horizontal evaporator and the orifice is at the end of the feed tube where it splits into 2 - a feed and return. 2. tap gently on the tube near the split and down the tube. The idea is to get the dirt away from the orifice. I used the plastic handle of a screwdriver. 3. Let it stand to give loose particles time to settle. 4. Reinstall gently. Needless to say this is pretty basic but sometimes spelling it out makes it easier for some of us. I did this process twice, first time failed so I used more patience the second time and it's been working for months. I do turn the refer off when I go sailing and turn it back on when I get to the anchorage. Still a little gun-shy about stirring up dirt on a rough sail. I will change it out at some point. Was there a link to parts? Here are some with pictures and part numbers. Here is the evaporator firstmatescabin.com/ref-evap-horiz/Add-on filter coastalclimatecontrol.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=CCC&Product_Code=A50030&Category_Code=accessI found it was very easy to tell if the system was working by watching the current draw. The system should take about 4.5 amps while working, perhaps 5.5 amps during the first few min after startup, if it was plugged it would drop to 2.5 and just sit there. Listening to the hissing works to confirm but I got faster feedback watching current. Gene
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Post by sailbleu on Mar 20, 2012 7:19:39 GMT
Thanks for the feedback Gene. It's kind of a mind easer to know I'm not alone in this frigoboat horror. The frustration in this matter is that the unit can perform for days , weeks , month(s) flawlessly , and then suddenly turns bad on me. You know I have 2 fridges on my boat , so in the past it was easy to shift temp sensitive stuff from one fridge to the other when the bugger ceased co operation. I only sail in the summer time (for now , that will change in 2 years time) , and last season my bilge got the beer/drinks cool enough sailing in Norwegian waters. But , since Portugal is on the list starting from juni , I need 2 operational and reliable fridges. That means I have to deal with the issue.
Get in a qualified technician right. Well , maybe I'm just bringing this story to far away , but many years ago I've installed a home airco , prefilled and quick fittings. Cant go wrong , but it did . I managed to overlook a few wires (shame on me with my degree in electricity) and it didn't work. Men and reading manuals right :-) I consider myself a bit as a handy man (like many of you boatowners) but had no expertise on airco's and fridges - although I understand the cooling process, it being a part of my professional life in the past , petrochemical installations you see. But the domestical versions , no , that was a bit of a mystery. So I had a professional in to correct the things I've done wrong , not knowing what they where at that moment. He didn't find the forgotten electrical wiring , I figured that out in later stage myself . But he did vacuum the evaporator (which wasn't neccesary due to prefilling) and added some (tiny bit) refrigirant. He was on the job for half an hour, left with a non working airco (the wiring remember) , and I had to pay him an equivelant of 130$ , no invoice thank you. I was so shocked for this outraging abuse I promised myself this would never happen again. I've been living with this ripoff trauma ever since , pledging myself I will move heaven and earth before surrendering myself again to vultures like that. It's not really the money you know , of course money always playes its part in life , but it's more the uncomfortable feeling of getting victimised as an ignorant average person. I really detest throwing myself to the mercy of the huslers of this world. Which doesn't mean that all professionals are robbers. But lets face it , we ask their help , and they're not giving it for our sparkling eyes is it not.
Back to the fridge , maybe Richard Kollmann will pay us another visite although I think he's slightly fed up with my naging. Cant blame him. Thanks for the links Gene , the filters pic gave me a clear view on how to disconnect the quick fittings. See the pic above with the red and black arrow , I wasn't sure how they interacted. Now I know. Again , when you look at the prices for the evaporators , a nauseous feeling would be a perfect definition dont you agree. Maybe I'll just consider my fridge as an experiment , most likely I will disconnect the evaporator , flush it , clean it , dry it and prefill it with refrigirant. Adding a second filter (not that golden one in your link mind you ) between the high pressure quick fittings and leave the compressor circuit for what it is. I will take pictures along the way and maybe present it to Malcolm for his hint and tips section if he considers it as valuable . All given that/if my attempt will be succesfull .
If in doubt , check it out.
Kind regards.
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Post by kollmann on Mar 20, 2012 15:14:04 GMT
Sailblue, I receive from 5 to 8 emails or forum items on boat refrigeration to answer per day so it sometimes it takes days to answer all questions.
To disconnect Frigoboat line connectors hold the medium size nut (Red Arrow) and only turn the largest nut (Black Arrow) in your picture.
Most refrigeration units do not follow the automobile industry standards for 134a refrigerant servicing equipment fittings. The gauge set you have will not connect to most of today’s standard ¼ inch flared condenser servicing fitting. You will need the older stile refrigerant gauge set and an adapter for yellow hose that fits 134a refrigerant bottle.
From your picture of refrigerant cans I can not see one that reads pure 134a and no additive. You do not want to add anything with extra additive to an already refrigerant flow problem.
When you determine it is not moisture and are sure it is solid material I would when replacing evaporator install a new larger filter dryer in evaporator’s liquid line and leave old filter where it is. Best solution is to cut and flare line using refrigeration flare nuts and a $14 flared filter/dryer.
I know you believe that restricted capillary tubes can some how be repaired but even Frigoboat suggest it is only a temporary solution on their units. If I were Frigoboat with refrigerant flow blockage I would offer the inline filter at cost not $165.
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Post by gene on Mar 20, 2012 15:57:31 GMT
Kollmann, I agree with everything you are saying. Cleaning is not an option, somewhere I read it can come from multiple sources including scaling inside the tube. The tube itself is so small that flushing is not possible. Moving the dirt up-line a bit is only a temporary fix. It will eventually fail again.
Replacing the evaporator is within the realm of repairs to an older boat. The $165 cost of an additional filter is just insulting. This problem is so widespread that Frigoboat should indeed help with some part costs. I would certainly NOT RECOMEND a Frigoboat system to anybody installing new. But then I am a bit cranky right now.
Gene
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Post by kollmann on Mar 20, 2012 17:44:13 GMT
GENE, Is your Frigoboat refrigeration unit a Keel Cooler model with the filter dryer mounted between evaporator and compressor instead of between keel cooler and capillary tube? These keel cooler models are the ones with problems of cap tube blockage Sailblue has the first air cooled BD compressor system I know of with refrigerant flow problems.
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Post by gene on Mar 20, 2012 19:40:18 GMT
My Frigoboat is air cooled. Boat is 1999 so it is a few years old however.
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