would you care to point out (picture perhaps) which hose that might be ? Inspite of the flawless running of my unit at this stage (due to condensor cleaning) I still keep a shortage of gas in the back of my mind also. Therefor I plan to be prepared and bring along a R134 cannister on my upcomming trip.
Oh and by the way , would anyone happen to know what the proper size is of the connection to add some refrigirant in the system ?
[a href=""][/a] It's the one in the centre on the right , a bit blurry and the cap is still on of course.
I have all sorts of car airco connections but none seems to fit. A picture or weblink would be great , so I have a reference on what to search for. Thanks
If your system is running flawlessly then it is not low on refrigerant. If it was low on refrigerant it would not work properly at all. It would never get down to temperature, and the compressor would never cycle off. It certainly would not work perfectly for an extended period and then suddenly stop, only to work perfectly again later.
Please heed the warnings by RLK and myself and don't mess with the refrigerant charge! I know the automotive industry has trained the general public to think it is normal to "top up" your a/c system on a regular basis. The fact is they are too lazy or incompetent to properly repair the system. (or the customer won't pay). An automotive A/C system is far more forgiving of incorrect charge, and contaminants for a number of reasons, which I won't go into right now.
As I said before, your system is called a "Critical Charge" system because it requires a precise refrigerant charge to function correctly. The reason for this is the nature of the metering device being used. The metering device is the component that creates the pressure drop that allows the high pressure liquid refrigerant to vaporize in the low pressure evaporator. Your systems use a long very thin copper tube called a capillary tube. It is so thin that you could easily mistake it for a piece of copper wire. That tube is of a very specific length and bore that is calculated to match the compressor capacity and evaporator of your system. It will meter the refrigerant through at a constant rate. (A car system uses a much more sophisticated Thermostatic Expansion Valve which can modulate based on evap temperature.)
Not enough refrigerant will result in the evaporator running warm, and the compressor running too hot because the refrigerant vapor returning from the evaporator is already too superheated to provide adequate cooling to the internal components of the compressor. running in that condition for long periods will cause damage to the compressor and ultimately lead to premature failure. Another problem with running low on refrigerant is that the compressor can start pumping its lubricating oil into the system. Small amounts of oil travel through the system in solution with the refrigerant, but if there isn't enough velocity or volume of refrigerant to return the oil it starts to accumulate elsewhere in the system. Typically it gums up the capillary tube that meters the refrigerant into the evap coil. Clearing or replacing a plugged cap tube is definitely not a DIY project! And of course there is the added bonus that because the system can't achieve setpoint and never shuts off, it kills your batteries far quicker than you would like when you are at anchor!
When the cap tube system has too much refrigerant in it you end up raising pressures throughout the system, on both the high and low pressure sides. Higher pressure on the high side, or condenser side, result in overloading of the compressor. The excess liquid refrigerant that is backing up behind that tiny cap tube waiting for its turn to go to the evaporator, will back up into the condenser coil which means there is less coil for the condensing process to happen in. Essentially you have reduced the capacity of your condenser. At the same time you are exerting more force trying to cram more liquid down that little tube. That brings us the the low side, or the evaporator side. The liquid refrigerant hits the evaporator and boils off, but because there is more refrigerant than the compressor can suck out the pressure is higher than normal there too. Higher pressure means higher temperature. (Temperature and pressure are directly proportionate in this condition) So once again you have a refrigerator that cannot maintain temperature, and once again it never shuts off and is killing your batteries, this time even faster because the compressor is drawing more amperage. but thats not all! If the evaporator is not capable of transfering enough heat to boil off the liquid refrigerant at the higher pressure, it will start flooding with liquid. Eventually that excess liquid will flood right back to the compressor. Liquid refrigerant is an excellent solvent of refrigeration oil, and it will start washing the lubricating oil off the cylinder walls of the compressor. (Imagine pouring solvent into the crank case of your engine!) If enough liquid floods back your compressor could try to compress a big slug of liquid. If you are lucky the compressor just stalls and cuts out on over current. If you are unlucky it breaks the intake valves and you need a new compressor.
And then there are the contaminants you can introduce to the system....
Not an uncommon problem! I have actually had success repairing plates with a certain kind of epoxy, but for what they cost you might as well replace it.
I have seen a good solution to beer can damage; a friend of mine made a can rack out of stainless steel that holds the cans on their sides in a vertical column on the side of the box. No more digging among the food for the beer! very slick!
Ok , i'm back again. still not out of the woods yet . A few weeks ago the fridge refused to cool again. After shutting it down for a day or so it was back in track. Last week the same problem.
I still believe there is a shortness of refrigerant. The evaporator turned warm and also did the compressor. I strongly believe those are the signs of a lack of gas no ? During these faillures there was no ledblink what so ever , so the problem is not electrically related. Could anyone help me out on how to get the proper coupling in order to add some refrigerant. See previous pics please.
If compressor continues to run after cooling stops there is refrigerant blockage do to moisture. if compressor stops running module senses an electrical problem. If you have a Frigoboat keel cooler model refrigerant maybe blocked temporally by debris from cooler.
When this type system is low on refrigerant or there is no refrigerant compressor will run and evaporator frost will cover less of evaporator depending on amount of refrigerant lost.
Moisture in refrigerant with correct amount of refrigerant will perform like this; Compressor starts running and evaporator frosts over. There will be a hissing sound anytime refrigerant is flowing in evaporator. Frosting begins to melt and hissing sound stops. Moisture freezes and thaws in expansion tube as temperature increases and drops in cap tube. If compressor is left running evaporator will remain at 33 degree F with no frost but cold condensation will continue as long as compressor runs. Also if unit has the correct amount of refrigerant current draw will be only 2 to 3 amps.
if moisture would be the (a) cause , than the disfunction of the fridge would happen on a more regulary basis , would it not , My problem only shows up once and a while. It lasts atleast half a day , sometimes longer. The warm evaporator and the compressor that keeps running and heats up I mean.
So it is as if there is no more refrigerant available to cool , and after sometime the remaining gas iin the system has settled down in the compressor again so the cooling process restarts , or can be restarted. Sometimes only the evaporator gets parcially frozen up and then suddenly defrosts and feels a bit cool with some condensation on it of course. In that last case i need to wait for a day or so (shutting down the power) , maybe longer , and then the fridge is back online.
You can understand this is a frustrating problem since it doesn't manifests itself all the time , making it very hard to determine what the real cause is.
The system has never been opened , so moisture or dirt can be ruled out I suppose , the first time the fault showed up was last year during the summertime.
I dont mind bringing in a professional , but what can he/she do when for instance the fridge is at that particular moment running smoothly ? I can only describe the symptoms and hoping someone recognizes them. I know I was given the advise not to tamper with the refregirant , but as far as i can figure it out , none of the possible options you and others have kindly given can be applied to solve my dilemma.
So , do you have any idea on where I can buy the proper coupling to add some gas ?
Typically intermittent refrigeration flow would be caused by a very small amount of moisture escaping from filter/dryer’s absorbing desiccant material. There are times where moisture can pass through the long capillary tube without freezing. If evaporator is cold enough moisture can freeze in accumulator section of evaporator and remain there until refrigerant velocity is high such as in warm weather or a warm start.
Frozen moisture is not the only cause of refrigerant blockage in capillary tube expansion tubes. Debris or scattered fragments left from manufacturing can block cap tube. Cap tube entrance opening on all refrigeration systems are normally protected by the filter dryer mounted after condenser or a small screen, this is not so on all Frigoboat units.
If you have confirmed as I described before the difference between refrigerant flow blockage and loss of refrigerant and concluded; Evaporator when system is cooling does not have frost on more than 70% of its surface area then refrigerant volume may also be low.
If you confirm the cooling and hissing sound in evaporator stops compressor continues to run then dehydration with a vacuum pump is required.
Zanshin , I'm well aware who Mr Kollmann is you know. I guess you wont require his assistance on your new boat very soon :-)
It must be said , my fridge' recent hickups did't bothered me that much. I'm just back from a 2 month trip to Norway , and the temps over there were not in the range where you desperatly are in need for a fridge. The whole bilge area was like a cooling cellar.
Never the less I would like to straighten up this grumpy fridge once and for all. Maybe dirt in the system could be the culprit. I dont think there is a filter for it in my unit. But in that case , why does the unit cools again after i have stopped it for a day or so ? If moisture would be involved , the cooling process would restart after the evaporator warms up. But usualy I need to wait for atleast a day or so (evaporator temp is well over +8 ° Celcius by then) before I make any chance on a succesfull restart ? This is really a mind boggler. Help !!
My last try, There is a problem pattern of refrigerant flow blockage on the type unit you have and they are aware if it. I described before how to separate moisture freezing blockage from solid debris. On any other cap tube system once tube is plugged with dirt it stays blocked because solid items on those systems are passed through a small filter and screen, this is not so on your unit. Go back to beginning of this thread and you will see your pictured location of filter that stops material from reaching condenser. What collects lose items in condenser and down stream from making there way to block cap tube on your type system? Nothing.
Owners of systems like yours with temporary and occasional refrigerant flow blockage problems are advised to replace complete evaporator assemble. In one case blockage occurred again and evaporator assembly was replaced a second time. A paper was circulated to tap on cap tube as a temporary fix. It appears the blockage item is larger than orifice in cap tube. Tapping on tube does seem to work as item falls back into supply line until it is moved back to tube inlet blocking it again.
Ok , this time I got the message. Thanks for filling in the story kollmann. As soon as you mentioned the fact that there are others with the same issue and that the faillure is related to debris in the system it became clear to me. This is for sure a manufacture fault.
My warranty on the unit has long passed date. I guess I'll try the tapping trick for a while. Installing a filter is too late I imagine. What if I would create a backflow on the evaporater ? Meaning , using a vacuum pump and fixing it to the connector of the tube going to the evaporator , maybe the debris gets pulled out because of to the backflow. Leaving me to refill the unit (or have it refilled). Could be an alternative for replacing the evaporator and the expence that comes along with it.
I am sorry to hear you are still having problems with your system. You are correct, intermittent problems can be difficult for a tech to diagnose unless he is lucky enough to catch it in the act. Typically what I would do in that situation would be to pull the refrigerant out, replace the filter/drier, purge the system with dry nitrogen, pull a deep vacuum and then re-charge with fresh refrigerant. Materials for such a procedure are not expensive, but it does take a few hours to do it right.
I am curious, when the system stops cooling, are you sure the compressor is still running? (I don't mean the condenser fan, it may run even if the compressor isn't.) Is the compressor unusually hot? Will it start working again if you just leave it turned on, or does it have to be powered off for a period of time before it will work again?
The things that come to my mind given the symptoms:
Moisture (not as likely with an unopened system but still possible) compressor overheating faulty compressor module
If the system works well when it does work, refrigerant charge is probably ok.
Another difficulty is to know when the error occurs. I do have a digital temp meter with a sensor in the bottom of the fridge . So whenever I see the temp running above 8° C I fear the worst and put my hand on the evaporator. Sometimes the temp elevating is due to a reshuffle in the fridge taking some food or drink out or in , but sometimes the evaporator is wet and then I know he 's in his period again. These days I immediatly check the compressor and together with the fan they are both on but not cooling ofcourse. The times a noticed the faillure after a conciderable time the compressor was infact heating up.
After realising the fridge doesn't cool anymore I immediatly stop the unit and try again after a day or so . Last year there where times I had to wait for a few days before I got response , meaning that the cooling process restarted with an evaporator turning cold . Next time it happens I'll try the tapping against the cap tube and let you know.
This is so frustrating , and completely replacing the unit is not what you would call economical. This trip I had the problem 2 times , the first was a few days after departure . The fridge was completely filled up -prices in Norway you see - and I had to reorganize everything from the main fridge to the backup. I have two units , see first page of this topic. A real mess.
Well, I would say what you need to do now is open your wallet and get a professional to look at it! It is great to do your own boat maintenance to save money, but there comes a time when you have to spend a bit! After all, you have a 40DS right? Worth $150-200k? Spending $500 for repairs on one of her systems is nothing compared to the value of the boat! Hell, you probably wouldn't think twice about spending that getting your car repaired!
Hi Schocktherapy , I completely agree with your point of view. Like I mentioned before , I dont mind getting some professional help but I also would like to be on the case myself. This way I know what is going on and be sure the specialist offers the best sollution. Confidence is good , but some followup is even better .Dont you think ?
But I'm sure this topic and all the info given here is or will be a good guideline for many others , including myself.
A few days ago the (my) fridge stalled again . The compressor kept running but no evaporator cooling. Nothing new you might think , in my case anyway.
But,..... this time I applied the ' tapping the captube ' trick as suggested by kollman , and guess what ?After some tapping on different places I heared a hissing sound of refrigerant entering the evaporator. Immediatly after that the cooling started. So now I know for sure it's not a lack of refrigerant , but contamination in the circuit that blocks the captube on occasion.
Leaves me to find the proper sollution , which no doubt will eventually result in replacing the evaporator and tubes. A job I'm not looking forward to.
Post by schocktherapy on Sept 13, 2011 3:21:19 GMT
Well, that is good news! you are that much closer to fixing the problem, because now you know you are dealing with a contaminant of some kind. You should not have to replace the evap plate or cap tube. As I said earlier, the standard procedure for dealing with contaminants is to remove the refrigerant, cut out the filter drier, and while the system is open purge the evaporator and cap tube and lineset with anhydrous nitrogen. Install a new filter/drier which should be around $25, and then vacuum pump the system to remove residual air and nitrogen, as well as any moisture that might be lingering in the system. The system should then be ready to recharge.
If there are some kind of solid particles causing the problem they should not be able to make it into the cap tube and evaporator coil, they would be trapped in the filter/drier. That is unless the filter drier itself is the source of the particulate; the desicant inside the drier that the refrigerant flows through is normally in a solid porous block, but if the drier has been impacted at any time, that desicant block can shatter. There is a screen that would catch most pieces, but it is possible that tiny bits could get through it and cause havoc with a cap tube.
Having said all that, if it were solids causing the problem, I would think that cap tube would just block up and stay that way. My money is still on moisture!
but I'm sure you read Kollman's contribution (see post august 10) about contaminents being a well known problem for my type of fridge , and the trick to temporarely solve it. Also - as far as I can tell - there is no filter/drier present on my unit. Apparently that's why this malfunction occurs. I am considering of cutting the line after the condensor and installing a filter/drier , that will give me a chance for flushing the system and getting a professional to fill up the system again (after the vacuum of course)
Post by schocktherapy on Sept 18, 2011 1:12:10 GMT
Your system does have a filter drier. At the beginning of this thread you posted pictures of your compressor. In the second picture, on the right hand side of the compressor there is a vertically mounted copper cylinder with the high side service fitting sticking out of one end. That is a filter drier.
I can't imagine why any refrigeration manufacturer would produce a condensing unit without a filter/drier! That is inexcusable corner cutting that violates all good refrigeration design!
Oh , I wasn't aware that was a filter/drier , I thought Kollman mentioned my type of unit lacks a component like that.
Here's the part where he referres to it: "My last try, There is a problem pattern of refrigerant flow blockage on the type unit you have and they are aware if it. I described before how to separate moisture freezing blockage from solid debris. On any other cap tube system once tube is plugged with dirt it stays blocked because solid items on those systems are passed through a small filter and screen, this is not so on your unit. Go back to beginning of this thread and you will see your pictured location of filter that stops material from reaching condenser. What collects lose items in condenser and down stream from making there way to block cap tube on your type system? Nothing[/b]. "
I'm a bit confused now.
I had the idea the item you point at was a expansion vessel of some kind. So replacing this alleged filter means cutting it out and welding a new one in ? The picture of member ' hoppy ' on april 15 gives a better view on the filter.
Maybe Kollman would care to specify what exactly did he mean by " Nothing ". But again , many thanks for keeping this topic alive. And judging by the number of hits , there are more gents interested in the outcome. Although I would appreciate some stories from other boat owners who were confronted with the same issue I have. This type of unit was build into many boats , and since - according to Kollman - this is a kind of a manufacturers fault , there have to be other ' victims '. I would love to read their story. Make us all a bit wiser dont you agree ?
Sailbleu, If you have confirmed that refrigerant’s temporary blockage is not ice then it must be caused by something solid that blocks capillary tube’s very small orifice opening. Solid blockage that can be dislodged allowing item to fall back into supply line can over time block tube again.
Capillary tube ice blockage can normally be identified by refrigerant flow controlled by moisture freezing and thawing in capillary tube. This off and on flow will result in evaporator’s temperature remaining at 33 degrees F and only condensation and no frost on evaporator. On a warm evaporator startup evaporator frost will appear to be normal until excess moisture again travels through system and again freezes in very long capillary orifice tube.
A special filter dryer is installed in all systems to catch solid material before it can reach capillary tube orifice tube. This same filter contains a desiccate moisture absorbing material capable of capturing and retaining a few drops of moisture for ever. After very small dryer is saturated with moisture any additional moisture will travel through system causing long term internal corrosion, if there is enough moisture short term freeze up in capillary tube expansion device will happen.
I think if you check with Frigoboat US they will advise you to: a. Replace evaporator’s complete assembly. b. Install a new larger filter dryer in liquid line to evaporator. c. Replace all O rings in line connectors. d. Dehydrate system for several hours at 100 degrees F.
Post by schocktherapy on Sept 20, 2011 3:51:31 GMT
Of course Frigoboat would advise you to replace the entire evaporator assembly; They make a whole lot more money that way! The procedure I described is what a competent refrigeration technician would do.
Many of the kits that are sold for boats have precharged evaporator assemblies that have the refrigerant piping attached and terminate with quick couplers attached. The condensing units are also precharged and have the other half of the couplers. the reason for this is so that their systems can be installed by the end user or the broker's handyman with minimal tools, equipment and skill required. The reason they advise replacing the entire evap assembly is because many of the people doing the work don't have the skills to do anything more than change parts!
Personally, 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.)
Kollmann, What exactly do they mean by "dehydrate the system for several hours at 100 degrees"?
It's always better for an amateur to leave the experts debatting and wait for the outcome before intervening . But maybe I should set a few things straight.
Kollman , the last time my unit failed , it was shutdown for a few days because my boat was about to go on the hard for the comming winter. Since yesterday his high and dry. So at the time when I was waiting (for more than a week) in the harbour for the hauling (harbourmaster was on vacation and is the only one allowded to work the lift) the temp in the fridge was at the time around 50* F , meaning no possible ice what so ever (in case moisture in the circuit is the culprit) . When I restarted the unit nothing happened , no cooling , no hissing , just the compressor working his butt off. I cut the power , disconnected the evaporator from his fixture in the fridge itself so I had a better view on where the captube's location . I turned the evaporator a few times around ,shaked it up and down , tapped several times on the spot where the piping narrows down in the evaporator , switched on the current , et voilà ......the hissing commenced and the cooling started. The fridge worked ever since. Now of course it's off. But to make a long story short , the succesfull restart was definitly due to fysical intervention and not because of ice melting in the captube. I would imagine that being sufficient proof for debris in the system no ??
Schocktherapy , I think that replacing the entire evaporator unit up to the couplers -as Kollman (and frigoboat) suggest - outrules any other blockage. Meaning that replacing the drier/filter and flushing the circuit to get rid of debris still leaves a chance of contamination left behind , blocking the captube again in a later stage. And it's not just that , I would think that getting a professional in to performe all the things you suggest will have a pricetag close to a new evaporator unit which can be installed by the average DIY . It's not just the houres , it's also the transportation to the harbour and so on. With all respect for your job and making a living , but repair prices of all sort are becomming out of control. In most cases it's cheaper to replace something rather than have it repaired by a pro.
Now I think I should leave the experts on speeking terms , so we might all get a bit smarter in the process.