Problems with Frigoboat/Danfoss fridge

[sailbleu]

And here we go again , I am aiming for 5000 hits on this topic .
Malcolm has promised me a bonus when we reach the target.
No , no , no , just joking of course .
Infact I would prefer the communication by means of PM , but then many others now and in the future would be deprived from the excellent info given on this board.

So why add a few more pictures to the story.
They do speek more than a thousand words dont they.

Yesterday I took matters into my own hands and went for the full monty.
I was able to connect the gauge set to the compressors low and high pressure so I had the correct readings to service the unit after the repair.


Gauge connected.


Low pressure after startup , this number stayed nearly the same after 1 hour in operation.


Same goes for the high pressure.



After shuttiung the unit dow and wait for some time I disconnected the quick fittings.



This is how the inside of the fittings look like.



So far for the easy part. Getting the evaporator out was a whole different ball game.




Jeanneau has managed to hide and stash the tubes behind a wooden wall.



Even tyrapping it in an impossible spot.



I'm getting there.



Not much room inside the fridge to shove the tubes through.



Actually this is a 2 man job , one pulling , one shoving , prevents bending the tube dangerously.
Looking at this pic made me deside to thoroughly clean the inside using my hull polish machine.
Over the years cleaning the fridge with abbrasive kitchen sponges scratches the surfaces thus allowing dirt to have a better grip.



Close to homebase.



The grand finale , the unit is in my workshop (garage) now waiting to be brutalised.Today's another day , and I will start searching for the proper fittings so I can begin the treatment I've planned.
I might just decide to cut the high pressure line and weld-in an extra dryer/filter instead of fixing one between the quick fitting.
Do I need to take anything sensitive into account while doing the welding Richard ? Do I braze with silver or plain soldering ??

Probably I'll end up making two quick fitting myself on the lathe . After all , I will need them to clean , dry , vacuum and refill the circuit.
Will fill you guys in on the progress , although I guess I'll be at it for week or so.

Regards

[kollmann]

Sailblue, I am disappointed you removed the refrigeration system without completely determining the cause of problem. If high and low pressures were in one hour running time as you say at 76 psi high and 6 low pressure this would confirm little or no saturated liquid was present in evaporator and only gas vapor. It would also confirm why the refrigerant flow sound is box was not always the same. Low high pressure could have been problem of intermittent refrigerant flow all the time. Either compressor outlet reed valve is leaking or unit is too low on refrigerant. I would bet low on refrigerant. Normal operating high pressure 10 to 20 minutes after startup is between 115 psi and 125 psi. In one hour evaporator will have a covering of frost and high pressure may be below 105 psi. If the system were still in tack I would have suggested adding refrigerant to achieve at least 110 psi high pressure.

I never advise a DIY person to solder or silver braze a liquid line filter to line, it takes an experienced technician to guarantee a clean open interior line. I always purge line with dry nitrogen while silver brazing. As I mentioned before ¼ inch flared filter with special refrigeration flare nuts is the correct choice.

[sailbleu]

Richard ,

now you've got me completely on the wrong foot.
I cannot imagine that tapping the evaporator and thereby getting the unit revived again could point out to ' low on refrigirant '.
This tapping method worked every time (sooner or later) .
Sometimes the compressor was running without the evaporator being frosted , no hissing no cold . After bashing it the whole process started. The last time the extreem heating up kickstarted the cooling again. It is my believe that the expansion from the capilar tube allowed the blockage to go through.
By the way , my evaporator never frosted partially , or it was completely frosted (in less than half an hour) or it was warm (when the blockage occured).

I'm also a bit confused here about the low and high pressure to what you refer to as correct values.
On 13 februari 7:44pm as an answer to Chris you mentioned 6-8 as the ideal number for the low and 50 for the high , which is exactly what my readings are.
In your last post you specify 110 as correct high.
You lost me there.

Would you care to share with us your opinion on the following item.
A Waeco evaporator with self-sailing quick fittings for half the frigoboat price.
Would that be an acceptable alternativ you think ?
www.sailormall.com/evaporator-waeco-vd07-019698-p-19698.html
If that one would be suitable I have something to fall back on.
I will continue to experiment with the old evaporator , try cleaning it and all , will add a new filter/drier also (they come cheap) .
I intend to clean the inside with aceton under pressure so it's kinda forced through the capilar.
I will collect the used aceton to check for any contamination.
Today I will fabricate the quick fitting adapters , had some old brass connection lying here that can be converted.
Wouldn't know where to buy the genuine separate fittings , and if I did , they will probable cost me an arm.
You know , this is - for me anyway - getting further than just solving a malfunction , I just need/have to know what caused the fridge to behave erratically.
I have the time , the tools and the temperament to go to the finish.
By the way , the inside of the fridge is already as brand new , spent a short afternoon on polishing it .

I'm sure many of you readers will think ..." hey , cut the corner and just buy a new evaporator ".
Your absolutely right , and in the end this is very likely what will happen .
But I simply have to know.

To be continued.

Regards

[kollmann]

Sailblue, You are correct, there is a chance that you are right and replacing evaporator and filter/dryer might correct your Frigoboat’s lack of cooling problem because a piece of material got passed filter and got stuck inside the 9 ft long .031 cap tube orifice. You then tapped on tube and unit started to work. If your system was a keel cooler model where it has happened several times before as solid materials are free to flow from compressor through keel cooler and block cap tube. Filter location is on suction line of keel cooler systems making your theory more likely on those systems. I have heard of replacing evaporators more than once on the same system that still did not solve a refrigerant flow problem on keel cooler models. If you do replace evaporator install a new larger flared filter on evaporator’s liquid high pressure line. WAECO’s Aeroquip line connecters are an improvement over Frigoboat’s but difficult to solder on and protect cleanliness of line interior.

I believe if I were you now that system is removed from boat I would connect it back together and run it. Unless it is extremely cold there you can add refrigerant till high pressure reaches 110 psi. When you reach 110 psi high pressure and low pressure is in a pressure range between 5 and 10 psi compressor reed valves look good and there must be normal refrigerant flow. Remember pressure readings in the first 10 minutes after start up are of no value as this is the system pump down phase. Normal evaporator refrigeration process begins after 10 minutes.

There are those who say they can tell by the sound of refrigerant flow in evaporator whether refrigerant charge is correct or not. In a normal Danfoss BD cap tube systems sounds heard as refrigerant is injected into low pressure evaporator will change as cooling temperatures in evaporator are reduced. After start up ten minutes compressor reduces low pressure and stabilizes it, there then will be a period of time where liquid refrigerant will contain a mixture of gas causing a pulsating sound in evaporator and even tubing between condensing unit and cap tube will vibrate. As box cools pressure drops and liquid sub-cooling improves reducing amount of vapor gas mixed in cap tube liquid. On one of my test stands I can create a restriction or blockage with a pack-less hand valve at beginning to cap tube. When refrigerant flow is blocked sound stops, low pressure goes into a deep vacuum, high pressure remains much the same and amperage drops in half. If this is the condition someone sees the question remains is blockage ice from moisture in refrigerant or solid material blockage.

You must first understand how heat is transferred from inside the evaporator to outside the area by refrigerant. Liquid going through phase change to a gas it absorbs heat, gas then carries away heat. Even water is a simple refrigerant. The difference between water and refrigerants is based on phase change temperature at sea lever pressure. Water boils at 212 degrees F and Refrigerant like134a boil at temperatures below zero F. Refrigerants all react differently as their boiling point and gas density are affected by pressure.

Refrigerant compressor only pumps gas vapor with a small amount of oil through a closed loop system. If it were not for a refrigerant restrictor control orifice, in this capillary tube, and a heat extracting condenser there would not be enough pressure and sub-cooled of refrigerant to liquefy gas. It also takes refrigerant volume density in system for refrigerant to be in liquid state when it reaches orifice tube. Pressure difference across cap tube control device will determine Btu and temperature performance for the system. These small air-cooled Danfoss BD compressor systems have predictable performance when condenser cooling medium temperature and both high and low pressure are known. One of these typical 134a refrigerant systems after 15 minutes with a air cooling medium temperature of 80 degrees F and warm evaporator will indicate 6 to 8 psi low pressure and 105 to 115 psi high pressure. I have been running tests on two test stands with BD compressors in my shop for over 10 years so I am sure the info above is correct for your system. Both high and low pressure normally changes as load and ambient temperatures change.

When refrigerant volume and flow pressure is correct evaporator will have a 100% cover of frost, although in a large or poorly insulated box frost cover may be very thin the first day of operation. If there is a small refrigerant leak evaporator surface frost will start disappearing at one end of evaporator and progress over time as more refrigerant is lost. Once refrigerant volume is so low that a liquid head of refrigerant is no longer interring capillary tube high pressure will drop to a point where only gas vapor will circulate without absorbing evaporator heat. Remember heat is only absorbed in liquid as it phase changes to a gas.

All of this brings me back to troubleshooting these Danfoss BD compressor systems.
• Always follow logical non destructive troubleshooting before destroying a simply good system. Calling a service technician will cost money and get advice to buy a new system in most cases.
• If Compressor does not run it is being told to stop electrically. If this unit has a BD 35 or BD 50 compressor and does no have a troubleshooting LED get one and install it.
• If a BD compressor runs continuously with no or poor cooling it is a refrigerant problem.
• Refrigerant loss on a well designed system is not common but it can easily be confirmed by a loss of frost on a portion of evaporator.
• Frost on return line to compressor indicates too much refrigerant or condenser is operating with a cooling medium colder than normal or refrigerant is contaminated.
• Restricted or blocked refrigerant flow problem: Solid material has in the past affected maybe one out of a thousand air-cooled systems with BD compressors. Common cause for solid material blockage is poor quality control by factory who assembled unit or by someone repairing or servicing system.
• Restricted or blocked refrigerant flow do to moisture in refrigerant that creates a low temperature limit on evaporator just above freezing as ice blocks refrigerant flow until it melts allowing flow again. Easily determined by continuous cold condensation on evaporator and no frost.

[sailbleu]

Ok , its been more than two weeks now and I guess I can -with relative certainty - say I have solved the problem.
Maybe it's wise to recapitulate the whole story in an well documented report so others can use it as a guide on what to do and what not to do when confronted with a Frigoboat/Danfoss fridge problem.
Malcolm is of course free to publish the essay on the hints and tips forum so it's easy to track and google it.
If he does it would be helpfull to also add the link of this topic since most of the interesting stuff are on these pages.

When reading numerous boards it is striking how many boaters , sooner or later, have issues with their fridges.
I can imagin that for many cooling techniques look like rocket science , but infact it isn't.
All you need are the proper tools , the time and the willingness to deal with the problem.
Getting advise from professionals like Richard Kollmann , Schocktherapy and others helps , no doubt about that.
I'm sure I made some mistakes in my approach , and I've picked up some things along the way .
But I did had my mind set on a blockage of the capilar tube and was certain it would be possible to remove the debri that was causing the malfunction.
I dealt with it on my own (non-professional ) way , but so far so good.
Here we go


Frigoboat fridge , well known system amounst boaters , of whom some are not that happy with.
Mine was give me hell for some seasons , letting me down on the worsed possible moments , to start cooling again as if nothing ever happened.
Bringing in a technician felt like having to write a blanck cheque and asking myself howmany times he/she would have to return to fix a problem that wasn't there all the time.



After some preparation - reading boards , asking questions here and there - I plonged in.
Getting the evaporator out , and try to get it working again.




Easier said than done , the copper tubes are fragile , it's like walking on eggs.




Jeanneau has done a good job hiding and tucking in the installation.




Not much room to fidle around.




If you ever get yours out - the evoporator I mean - try bringing in a helping hand . This way you prevent damage to the interiour.




Getting the package to neutral territory , my workshop .



First things first , getting hold of the proper male/female connections to do my thing.
Not that easy , I searched the net but couldn't find. Left me making them myself.
I had some usable connections stashed away .




Again , when you have the tools , the sky is the limit.




That's the male , and it turned out I didn't need it. But it was fun to make.




Getting the self sealing couplings off the evaporator circuit so I could start flushing it.




And why not spend a few words on the how these couplings work.
This picture shows the back end , the part that screws on the tube(s).




Very obvious how the sealing principal works.
Well , let me tell you something about those selfsealing couplings,.......they dont seal !!
Due to family obligations I wasn't able to focus on the evaporator right away. I left it for a few days and had to establish the refrigerant was gone.
I blamed it on my initial probing of the couplings . After bringing the evaporator to my workshop I immediatly checked the resistance of the springs inside the coupling , letting some gas out of the high pressure side ,as a test.
I was wrong , it wasn't the probing that caused the leakage , it's the weak design itself. I suppose you normally need to cap all the couplings preventing a refrigerant leak. How was I to know that the compressor was undergoing the same fate.




Now this is a very interesting picture. Once the high pressure coupling was off I noticed a small filter inside the capilar tube. No explanation neccesairy I presume.




That got me off balance. How could the capilar (orifice) get blocked by drifting debri when this fine mazed filter was there to bring it to a halt. By the way , I did not find any particle on this filter.




Anyway , I had my plan of attack in mind and had no intention of deviating.
After making (improvising) a connection to the tubes I could bring in the aceton.
I completely filled the evaporator and tubes with that degreasing produkt , then it was time to push it out again.




Using an air compressor and airgun blsting 10 to 12 bar air through the system collecting the aceaton that was squirting out so I could check for impurities. And there where some , a bunch of tiny black things.
I flushed both ways .
Again , it really boggles my mind , I was expecting more rubbish .
The high pressure filter was clear which was in contradictian with all the horrible stories of occasional drifting debri.
I cant help it , but I keep thinking back to the time I had the evaporator heated up to a point where it had never been heated up before and where the fridge suddenly came through.
See post Reply #62 on Mar 16, 2012, 7:42am
Maybe , just maybe the culprit got blown into the compressor's suction for good.
The lord works in mysterious ways I guess.




Getting the aceton out afterwards was crucial , that is no doubt an impermissible substance in a cooling system.
Igniting the outcomming mixture would indicated when all the aceton was removed.
I would deal with the remaining air afterwards.
Please note I did remove the rubber O-ring after this picture




Not being sure that the old filter/drier was still up to the job , and to eliminate moisture in the system I decided to add a second filter/drier in the high pressure line.
And instead of using the ' golden ' filter that can be bought on the internet (Gene Santosha supplied the link earlier)http://coastalclimatecontrol.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=CCC&Product_Code=A50030&Category_Code=access
I decided to make one myself.
This one costs about 5 Euro's shipment included.




After welding on the the right connections ( which I had in store , lucky me) I needed to make a few bibs and bobs to fill up the evaporator system with refrigerant before reconnecting it to the compressor after installing everything.
I was still confidant the compressor remained loaded with refrigerant , how wrong could I be.




So , that 's settled ,.




Drying the aluminium oxide in the oven.
I often do that when I refill the filters of my scubatank-compressor.
Capping the (filter/drier) ends prevents moisture in the filter.




Once the evaporator and compressor where back on the boat , and after wrestling with the evaporator to get it back in again , it was time to fill and flush the evaporator circuit.
I didn't bring my vacuumpump because I was still under the impression that the compressor was full.
Using the pump on just the evaporator system was of noi use I thought. I would flush the air out.




Just a picture of my repainted compressor , isn't that a beauty .
I even polished the SS casing , leaves me to the make a printout of the label that was removed for the paint job , stick it on and this compressor looks like it's straight from the store's shelf.
The white sparks on top are dust , just that you know




After refueling the evaporator circuit and flushing generously with refrigerant to get the air out , reconnecting the compressor was the first goal.
I read somewhere that is vital to install a filter/drier vertical. That way the refrigerant is forced to pass through the AluOxide .
When placed horizontal it can slide over it you see.
Then I was in for a cold shower.




After connecting everything it was showtime.
Starting the unit and checking all the pressures and evaporator cooling.
And you know what ?
Nothing happened.
The low pressure was indicating a vacuum , meaning a lack of refrigerant.
There is such a thing as causality , and the evaporators leaking selfsealing coupling had me presume the same thing occured to the compressor.




Ok , time to get in the reserve troopers.
And you already had a glance on the gauges right ?
Suction is perfect , discharge pressure was as Richard Kollman said it has to be.
And here I would like to appologize to him concerning a remark I made in the following post Reply #77 on Mar 22, 2012, 5:48am »
I implied that he said earlier the high pressure should be 50 PSI.
That was not correct , because after reading all the posting again he clearly stated the high pressure should be 100 to 110 PSI.




After some running time (the fridge was cooling like a mid-winter day on Antartica) I noticed the pressures rising somewhat , also the compressor suction was freezing up . That could only indicate too much refrigerant.
Venting a bit was the proper answer.
Remember folks , this is eco-friendly gas.
Just thought I mention it.




Better safe than sorry , soaping all the connections is a reassurance .




To give you an idea on the cooling capacity .
That is Celcius by the way !




I had this gadget on the boat before adressing the coolunit .
These displays gave me the temp indication of both my fridges.
I always thought it looked kinda amaturish , so why not do a proper job and installing a state of the art tempcontrollers.




Removed the old panel and made a new one.
These controllers are the real deal .
You guy's (some of you atleast) dont know what these cheap (Chinese) things can do.
They not only give you the temp , the build-in relay can switch whatever you want , be it a heater or be it a coolunit.
All depend on the setting you make.
The top display is my small fridge , something I made on my own , but that's an other story.
The bottom display belongs to the frigoboat fridge.
The small fridge (top) is not working , so the temp is the atmospheric one (not too warm here isn't it )
On the other you a small led on the left side . That shows the fridge is running.
As an extra , I disconnected the original frigoboat thermostat and both fridges are being controlled by these nice displays.
They allow you not only to set the working temps , you can also set a delta T . Meaning , stop the compressor on (as an example) 3° C , and have it restarted on (for instance) 5 °C .
You can even set a compressor delay of max 10 minutes , that will translate into a blinking led telling you that the comp will start after the preset time. Always a good thing to prevent torque blockage when you start/stop/restart a cooling compressor. It can and probably will stall and worse.
With a push of a button you can turn this fridge controller into heating thermostat too.
Choices , choices , choices.
Let me share the link with you

www.ebay.nl/itm/270934968818?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
I had the temp set on minus 5° C .
Here the temp was already minus 1,1 ° C and dropping.
My fridge is back with a vengeance




The sensor is way down the fridge , there are pro's and cons for that. I tried to deal with that in the next pic.




A small ventilator circulating the air ever so gently around the inside. The vent will only be operational when the compressor is on. It's pointed to the evaporator to capture the cold and spread it around.
I know , creating a circulation in a fridge has equal advantage as it has a disadvantage.
The cold will be uniform , but maybe the power consumption will rise due to the fact that there will be more heat/cold transfer on the inside walls.
I'll just wait and see , the vent can be disconnected in a blink of an eye.




Finishing touch , tywrapping the tubes so no vibrations can cause..... whatever.




Case closed (I hope )

[MalcolmP]

Malcolm is of course free to publish the essay on the hints and tips forum so it's easy to track and google it.
If he does it would be helpfull to also add the link of this topic since most of the interesting stuff are on these pages.

Sailbleu - most impressive, you have certainly shown resilience and persistence in this when lesser mortals would have given up long ago. Well done - I will probably do just a summary for Hints and Tips which then directs interested readers back to the detail in the forum pages

[mraphael]

I finally found the problem with my fridge -- turned out the quick release fitting was actually cracked, allowing the refridgerant to leak. We ended up cutting out the broken fitting, and welding a continuous line (splicing the two lines). the unit has worked fine ever since.

[sailbleu]

No pics mraphael ?
I'm also very interested in other stories you know.
Where exactly was the crack situated ?
No doubt you had to vacuum the complet system , did you do everything yourself ?
In your case - welding a continuous line - there could be a future problem with regards to dismantling the system for let say an other repair .
Hopefully for you this will be your last fridge-issue for a long time.
Infact , does anyone know where to buy the separate selfsealing (?) couplings ?

Regards

[schocktherapy]

Well, Sailbleu, I am impressed! You fabricated your own couplings?!

Full marks for persistence!

While it is clear that you have absorbed much of the information, and for the most part interpreted it well, you also made it FAR more complicated than it had to be!

First of all, there is no reason you can't purge the evaporator without removing it from the boat. Simply disconnecting it from the condensing unit would suffice. I cringed when you said you used acetone in the coil, because any remnants in the system could cause trouble. But as long as you go it all out, I guess it's ok. (The black bits were probably oxidation from the inner walls of the tube from the original brazing, washed off by the acetone) Ideally you should use dry nitrogen to purge rather than compressed air which has huge amounts of moisture in it!

You went to great lengths to preserve the quick couplings, and you even added more threaded connections! You would have been better off cutting all of the couplers off and brazing or even soldering the joints. All of those connectors are potential leak points. They will leak sooner or later, that is the nature of the beast!

Good call replacing the filter drier, but again I would have brazed it in, and you should ALWAYS remove the old drier. If the desicant inside is saturated, it can release some of that trapped moisture back into the system in some conditions.

Nice find on those thermostats! They look far nicer than the factory part!

I'm glad your system is finally working! Hopefully it will behave itself for years to come!

p.s.

I still say it was moisture in the system! :-)

[schocktherapy]

Apr 16, 2012 22:12:04 GMT mraphael said:

I finally found the problem with my fridge -- turned out the quick release fitting was actually cracked, allowing the refridgerant to leak. We ended up cutting out the broken fitting, and welding a continuous line (splicing the two lines). the unit has worked fine ever since.

Good call getting rid of the couplings. Hard piped is best, and if you ever need to get the system apart again, a cheap tube cutter is all you need!

[kollmann]

[quote author=schocktherapy board=general thread=1623 post=10162 Good call getting rid of the couplings. Hard piped is best, and if you ever need to get the system apart again, a cheap tube cutter is all you need![/quote]

Only if line contains no air only dry nitrogen inside while soldering to help prevent flux and slag deposits inside. Refrigerants are great cleaning agents and over time will wash deposits into capillary tube. Solution for DIY person to connect refrigerant lines or to install a new filter/dryer is to use standard special refrigeration flare nuts, they will never leak or block capillary tube.

[schocktherapy]

Agreed; brazing and soldering should be done with an inert gas in the lines, however no amount of nitrogen will prevent "slag" or flux from getting into the lines. They are a result of poor technique.

In Sailbleu's case, he had to solder his new couplers onto the pipe anyway, so he knows how to do it, so why not eliminate the couplers and just hard pipe it?

I strongly disagree that flare nut connections "never" leak! They do! The only argument FOR flare nuts is on the filter drier, because it makes it easy to change the drier in the event of a future system contamination. Of course if the system is as leak resistant as possible you won't need to change the dryer again for a long time!

Flare nuts CAN leak, and that is a fact!

[kollmann]

Schocktherapy, Will you agree with me that in manufacturing Nitrogen, Argon or Helium gas is common practice to prevent copper tube interior of solder joints clean and free of deposits and that in the field good technique can not always prevent later problems. After providing technical services for over 50 years to DIY and experienced technicians I believe advice should keep them out of trouble and not get them into trouble. It sounds like sloppy solder joints may have been Sailblu’s problem all along based on black particles fond, so risky advice is sometimes dangerous if followed.

A properly flared copper tube with correct heavy refrigerant cast flare nuts will not leak when tight. Soldering ¼ inch joints need to be done in a controlled atmosphere when there is a risk of process oxides causing serious system shutdowns in the future.

[schocktherapy]

I have consistently said that brazing should be done with inert gas in the pipe. In Sailbleu's case, he was aware of the risk and chose to solder or braze new quick couplers onto the pipes. My point was, if you are going to take the risk of soldering, why not at least eliminate the known leak potential that the quick couplers constitute?

My opinion on flare nuts is that they have their uses, but they also have their drawbacks. When I am installing a system I don't use them, just as I don't use quick couplers, and my systems don't leak! What the DIY boat owner does with that information depends on what skills he has, and what materials and tools he has access to.

The bottom line is that a system that is hard piped will be more far more leak resistant than one full of flare nuts and couplers.

[kollmann]

Schocktherapy, then you agree that this boater's problem could have been caused all along by soldering by products?

[schocktherapy]

It is possible of course, but if that were the case the system would have had problems from new. The filter/drier would pick up anything in the system before it gets to the cap tube. The only exception would be any soldering or brazing done on the liquid line between the filter and the cap tube. I sincerely doubt that the factory soldering could be the cause of the problem.

I am curious about the black bits he found when he did his acetone flush. Acetone is a far more powerful solvent than R134a, so it is possible that it scrubbed off deposits that the refrigerant couldn't. It is also possible that they were a result of his own soldering. They may have been introduced to the system during initial install, if the installer didn't make sure the couplers were free of debris before connecting them. it could even be residual refrigeration oil after it has reacted with the acetone. Regardless, if they came out of the evaporator, then they either already passed through the cap tube, or they were trapped in the evaporator all along, in which case they would not cause any problems with the cap tube. If they came out of the liquid line upstream of the cap tube, then indeed they may have been the culprits!

We will never know for sure what caused the problem, and we have certainly explored all the possibilities!

The important thing is that Sailbleu took on the challenge, and it looks like he may have solved his problem. Along the way he picked up alot of solid information that will help him the next time he has a problem. Perhaps he will use it to help a fellow sailor at some remote anchorage somewhere!

[kollmann]

I would have given up on this thread of posts except for the resent rash of refrigerant flow problems in small Danfoss powered icebox conversion units. History shows each boater experiencing refrigerant flow problems on these ¼ inch OD tubing systems can expect to spend from $400 to $3,000 in some cases just to kick problem down the road and experience problems again. The problems of refrigerant flow restrictions and total blockage are linked to systems assembled by DIY and so called job shop service engineers. I helped litigate two of these cases involving blockage from soldering and refused to give a deposition on another.
The only ice box conversion manufacturer that seems to have problems with refrigerant flow blockage is Frigoboat and hopefully they are taking steps on current production models to resolve future blockages. Unfortunately most of the time these blockages do not show up until after warrantee expires and maybe it takes five years.

This will be my last post on this thread. I try when giving advice especially to DIY boaters to make sure it is the least destructive direction possible in this case keep it clean and stay from soldering.
I have a new web site and boat refrigeration forum in progress many of the archives from old forum are there. I will try to group normal system problems together in future posts.

[schocktherapy]

It should be noted that Danfoss is the compressor manufacturer, and in my experience they are very reliable and efficient units. They cannot be blamed for poorly built kit systems they are a part of. I can't speak to the quality of Frigoboat products as I have not worked on or installed that brand. When I was installing boat systems I used NovaCool systems, and found their quality and reliability to be top notch.

Any refrigeration system is only as good as the installation. As anyone who has been following this thread will realize, there are alot of things that can go wrong. In my opinion DIY kits are a huge compromise, and are by no means foolproof! My advice to anyone wanting refrigeration on their boat is to consider spending a bit more money to have a qualified refrigeration technician install a custom system rather than a precharged kit.

While Kollmann is offering all kinds of good information, I take issue with his constantly referring to "destructive" methods. Putting gauges on a system is not "destructive", it is a valuable diagnostic tool. Brazing and soldering joints is not "destructive" it is the most secure and leak resistant way to connect pipes in a system. these are the CORRECT methods to use on a system. It is true that both can introduce contaminants into a system if done wrong, but so can quick couplers and flare connections.

[kollmann]

I standby my advice that hiring a so called qualified refrigerant technician or anyone else to connect any device to a system that holds only 80 grams of clean pure dry refrigerant is doing destructive testing when there are non destructive means available to determine performance problems. I also consider advice that risks future system failures like soldering small lines in the field when expansion device is not adequately protected is dangerous and foolish advice.
I find that in many cases boaters that first call a service engineer when non destructive testing done by captain would have found and corrected problem. For thirty years or more refrigerator companies including companies like Adler Barbour did not provide a refrigeration servicing ports on their units and the reason why was to prevent over zetas so called service techs from tampering with critical refrigerant.

[shiook]

Thank you for your input on this topic. Great information.

[ianqv]

WOW!! Many thanks for all the info posted here!

Just one question, I am about to re-gas my system with 134A
But…. How do you know how much gas to put in?

Many thanks

Ian

[kollmann]

Refrigerant servicing procedure will vary depending on system’s condition, System design, and past history of system that makes it necessary to add refrigerant.

Low on refrigerant means simply add correct amount of pure refrigerant approved by compressor manufacturer for that system.
Different procedure system opened up and exposed to air.
Different procedure for different evaporator types.
Different procedure for different refrigerant flow control devices.

You do not need to be an expert when adding refrigerant to a small refrigerator but you do need to know more than most service technicians.

[sailbleu]

Ian ,

sorry for saying , but it looks you did not read all the postings and did not look at all the pictures.
First of all it has been explaned by Kollman and Schocktherapy (many thanks for their last postings by the way) extensively, and I think I myself -by means of many pics - have illustrated how to check the pressures and all.

Anyway , my fridge has been cooling for about a month now , ever so willingly.

Regards

[ianqv]

OK - after having my wrists slapped I've now read word for word...
However, I think I have even more questions now!!!
So please bear with me if I appear stupid (thats because I am!!!).

To prove I've done my homework the answer to my question was high pressure 110 psi. and low pressure range between 5 and 10 psi, however, let everything run for at least 10 mins to settle down.

Back ground to my concern - everything still works, BUT I think it should be colder.
I don't have pressure gauges (yet) so I will confirm wat is happening on that side of things soon. I also need to check the temp in the cool box.

However.... I have visited the frigboat website and read theiir tech support advice. Esp their diagnosis part regarding how to identiy under / over gassing.

This is what frigo say........

Slightly undercharged system
If there is too little refrigerant in the system, it will have evaporated back to a vapor before it reaches the end of the evaporator. Some of the surface will have a coating of frost, but from the point where the refrigerant has turned all to vapor, the surface will be cold and sweating. The frost begins at end of the capillary tube, where the liquid refrigerant is fed into the evaporator. The evaporator will probably sound the same as a properly charged system.

Seriously undercharged system
If the system is seriously undercharged, the refrigerant may exist in the system only as a vapor, and so there will be no frosting on the evaporator, just a slight sweating and coldness to the touch. In this condition there will probably be a constant hissing sound from the evaporator. This sound is important in identifying if the system is undercharged or overcharged.

Slightly overcharged system
Too much refrigerant in the system will result in liquid still evaporating back to a gas past the end of the evaporator and inside the tubing going back to the compressor. This means that there is still some of the refrigeration process going on inside the tubing, and there will be a build-up of frost or ice on the exposed section. If additional insulation has been added, it may be concealing this symptom and should be removed. The evaporator may appear and sound normal, but will be at a higher temperature than desired, resulting in longer than expected run times.

Seriously overcharged system
If so much refrigerant exists in the system that it raises the temperature of the evaporator above 32 deg F, the surface will only be sweating and cold to the touch, resembling an undercharged condition. But the copper lines leading back to the compressor, and maybe even the compressor itself, will also be cold and sweating, and there will probably be a sound similar to a mountain stream coming from the evaporator. This is a potentially damaging condition as liquid can reach the compressor where it can damage the valves, since refrigeration compressors are designed to compress gas only.

So....... with the above in mind - the attached image was taken after approx 50 mins of running (with the thermostat on 7... its coldest setting)



So am I right in assuming I "could" have the right amonut of gas in the system?

Many thanks in avance for any help offered

Regards

Ian

[sailbleu]

I would guess if you see that , the frozen tubes , there is definitly an overcharge of refrigerant.
If you do not have the gauges (which I think is the case) to check the pressures , vent some refrigerant and wait a substantial amount of time.

EDIT:
I just read the part where you say you dont have the gauges.


Keep doing that untill the frost on the suction tube is gone.
If the fridge is still cooling 100% you are there.
I'm sure the professionals on this board will get the shivers reading this procedure , but in your case it's working with the means at your disposal
Oh yeah , and when you vent on the discharge cap , use a rag to cover it, the refrigerant and the oil in it stains.

PS:
you say you are re-gassing your system , what happened to it in the first place ?

Regards