18 year old refrigeration -- fix it or ditch it?

[Dockhead]

So my boat has two separate Isotherm reefer systems -- one for a front-opening Isotherm refrigerator, which has the evaporator hidden behind the back wall, and the other for the top-opening freezer. Each has its own Danfoss BD compressor and Isotherm SP special through hull condensor.


Both have had very slow leaks for years, which have required me to top them off with a small amount of gas about once a year (using Kollman's excellent instructions and a can-tap device).


I have been very happy with this system which is almost silent (had air cooled on the last boat which made a significant racket), and efficient enough that it even works with the boat on the hard -- even in hot weather. I guess with the boat in cold water, as she usually is (rarely over 10C), this system must be very efficient indeed.


But now the refrigerator one has started to leak more. I might have pushed and pulled the copper lines too much when I replaced both sea cocks the special through hulls are attached to. This now seems too much, so what to do?


I've heard these systems leak at the connectors, and I suppose I could probably find the leak, then hire someone to come vacuum the system down and refill it, but is it worth it? I thought these cheap Danfoss jobs were supposed to be basically disposable -- won't I be pushing my luck trying to get more than 18 years out of it?


Or can they go on and on, and I shouldn't get rid of a perfectly good one? I've never had a controller problem or actually any problem at all over all these years, other than the slow leaks.


Grateful for tips.

[JPA Cate]

Hi, Dockhead, "basically disposable" is a notion. Ours is 28, 29 in August, little Danfoss compressor, happily making cold happen. If you're okay to throw out things because they're old, that may be irrelevant to you, but it is evidence that up till now it is not "disposable," at least for cheapskates like me.

I'm pretty sure that a refrigeration specialist may tell you to replace the whole lot, and maybe that would be a better deal for you.

Ann

[Dennis.G]

You can have small leaks in a new system too. Would recommend checking fittings with soapy water, but leaks can be difficult to find this way. Pros have sniffers that can find very small leaks quickly. Chances are a refrigeration tech could find and fix leaks, evac and fill system and have you running in a few hours. If only problem with system is a leak, I say get it fixed.

[OzePete]

Hi Dockhead. There is some good advice here from previous posters but may I also suggest that once the leak is located and fixed, have a proper filter dryer like a Sporlan 032 or 052 (flared) fitted before evacuating. Unlike the spun copper types these also have a felt filter internally and do actually filter correctly.

Also if replacing coupling O rings make sure the replacement O rings are rated to suit the refrigerant used... most likely R134a.

Cheers OzePete

[s/v Jedi]

My system was built by me in 2004 and is on it's last legs today. My recommendation is what I have decided to do: rip it all out and replace with large drawers that hold the portable Engel/Dometic fridge/freezer boxes.

I have had a Dometic box in the basement of my motorhome for a couple of years now and it's terrific. You can buy a drawer-style tray for them but I would custom-build to fit into the galley. There is still enough room above it for a nice storage drawer. I planned two drawers next to each other each holding one, plus a 3rd unit in the pantry

[Dockhead]

Originally Posted by JPA Cate

Hi, Dockhead, "basically disposable" is a notion. Ours is 28, 29 in August, little Danfoss compressor, happily making cold happen. If you're okay to throw out things because they're old, that may be irrelevant to you, but it is evidence that up till now it is not "disposable," at least for cheapskates like me.

I'm pretty sure that a refrigeration specialist may tell you to replace the whole lot, and maybe that would be a better deal for you.

Ann

Electro-mechanical devices have useful lives. Danfoss compressors are cheap and apparently not very robust. If this is the end of the possible life span, then it would be waste of money trying to fix it.


If on the other hand, people are getting 28 years out of them (!), then that's a whole different matter. That is exactly the kind of data point I was after; thank you!

[Dockhead]

Originally Posted by s/v Jedi

My system was built by me in 2004 and is on it's last legs today. My recommendation is what I have decided to do: rip it all out and replace with large drawers that hold the portable Engel/Dometic fridge/freezer boxes.

I have had a Dometic box in the basement of my motorhome for a couple of years now and it's terrific. You can buy a drawer-style tray for them but I would custom-build to fit into the galley. There is still enough room above it for a nice storage drawer. I planned two drawers next to each other each holding one, plus a 3rd unit in the pantry

Thanks; and another good data point!


15 years. Why is it "on its last legs"? Leaking? Control board?

[Dockhead]

Originally Posted by OzePete

Hi Dockhead. There is some good advice here from previous posters but may I also suggest that once the leak is located and fixed, have a proper filter dryer like a Sporlan 032 or 052 (flared) fitted before evacuating. Unlike the spun copper types these also have a felt filter internally and do actually filter correctly.

Also if replacing coupling O rings make sure the replacement O rings are rated to suit the refrigerant used... most likely R134a.

Cheers OzePete

Cheers.

[Richard Kollmann]

Originally Posted by Dockhead

Electro-mechanical devices have useful lives. Danfoss compressors are cheap and apparently not very robust. If this is the end of the possible life span, then it would be waste of money trying to fix it.


If on the other hand, people are getting 28 years out of them (!), then that's a whole different matter. That is exactly the kind of data point I was after; thank you!

Your unit has several places to look at for leaks so before spending money on a technician or thinking about replacement I recommend you look for the leaks with this method.
First add only pure R134a refrigerant with no additives till pressure between bottle and system are equal.
Use a 50/50 mixture of liquid dish washing soap and water, and apply it to each connection to be tested. Agitate mixture on fitting with small paint brush to create shaving cream foam by stabbing it with brush tips to break down surface tension. Look for bubbles. If leak is at one of disconnects tighten it only 1/8 of an inch after it feels tight.
Possible leak areas to test for leaks on that system are:
Seal under servicing cap cover.
There are three O ring seals and two solder joints on each line connector.
New O rings are available from most auto parts stores.

It will take at least five minutes watching each test point and it will show 1/2 of an ounce refrigerant leak over one year For better than an electronic detector.

The two leak areas to be concerned about are the through hull condensers and evaporator plates even if they are eutectic plates.
Question on through hull condensers are their zincs well maintained? Small leaks here are hard to find.

If after leaks are found and corrected ice begins to freeze and thaw in cap tube then you need to consider dehydration vacuuming complete system that also takes care of moisture in filter dryer.

Good Luck, Email me if you need additional help.
Richard

[Dockhead]

Originally Posted by Richard Kollmann

Your unit has several places to look at for leaks so before spending money on a technician or thinking about replacement I recommend you look for the leaks with this method.
First add only pure R134a refrigerant with no additives till pressure between bottle and system are equal.
Use a 50/50 mixture of liquid dish washing soap and water, and apply it to each connection to be tested. Agitate mixture on fitting with small paint brush to create shaving cream foam by stabbing it with brush tips to break down surface tension. Look for bubbles. If leak is at one of disconnects tighten it only 1/8 of an inch after it feels tight.
Possible leak areas to test for leaks on that system are:
Seal under servicing cap cover.
There are three O ring seals and two solder joints on each line connector.
New O rings are available from most auto parts stores.

It will take at least five minutes watching each test point and it will show 1/2 of an ounce refrigerant leak over one year For better than an electronic detector.

The two leak areas to be concerned about are the through hull condensers and evaporator plates even if they are eutectic plates.
Question on through hull condensers are their zincs well maintained? Small leaks here are hard to find.

If after leaks are found and corrected ice begins to freeze and thaw in cap tube then you need to consider dehydration vacuuming complete system that also takes care of moisture in filter dryer.

Good Luck, Email me if you need additional help.
Richard

Thanks; very helpful as always


But back to the original question -- do these units last long enough, to be worth messing with at this age? Is it common for people to get 28 years out of them as the Cates have?

[sailorboy1]

Mine is 18 years old and is running fine with no issues.

[Dockhead]

Originally Posted by sailorboy1

Mine is 18 years old and is running fine with no issues.

Isotherm?

[OzePete]

Originally Posted by Dockhead

Thanks; very helpful as always


But back to the original question -- do these units last long enough, to be worth messing with at this age? Is it common for people to get 28 years out of them as the Cates have?

There is no way of predicting the life of a compressor except to say that they will usually last virtually indefinitely if never 'opened' and properly maintained.

When manufactured and applied to a system, the manufacturer usually practices correct industry procedures which means the system, oil and refrigerant are perfectly clean and dry.
It is what happens thereafter that determines how long the compressor will last. Gas leaks especially on the systems low side (evaporator) not repaired correctly and leaving contaminants in the system, is a major cause of reduced compressor life. Most compressors die due to poor repair practices.

If a system has been 'open' or had gas leaks not properly repaired, then the compressor life will be compromised, otherwise it should be good for many more years but only if the present gas leak is located and properly sorted as described my earlier post.

Cheers OzePete

[Richard Kollmann]

Originally Posted by Dockhead

Thanks; very helpful as always


But back to the original question -- do these units last long enough, to be worth messing with at this age? Is it common for people to get 28 years out of them as the Cates have?

The Danfoss compressor is only life limited when operated excessively warm.

The aluminum evaporator does display end of life is coming when the protective coating shows signs of aluminum blistering underneath. Leaks in these evaporators begin as a micro leak and multiply in size and number over time. An evaporator leak requiring added refrigerant once every six months will grow to adding refrigerant every 6 weeks. Remember this systems correct refrigerant charge is around 3 ounces by weight.

Through hull condensers if low voltage discharge is not controlled and discharged elsewhere could be a problem. Right now the only problem with through hull condensers is keeping them clean to prevent overheating compressors.

I Always recommend boaters find and confirm a problem with the less expensive non destructive methods FIRST.

[a64pilot]

I’ve had a couple of the electronic sniffers.
They are not nearly as good as soapy water, I even tried using them to find wing leaks on new built aircraft wings by putting some R-134a in the wing, they would alarm, but nearly useless for pinpointing the exact location of a leak.
Soapy water in a squeeze bottle like one used for rinsing out your ear is best, that way you can dribble soapy, but not sudsy water slowly over a fitting. If it has bubbles in it already it’s not as good as pure liquid for finding tiny leaks.
I’m no refrigeration manufacturer, but a “sealed compressor” is honestly about the longest lasting mechanical contrivance I’ve ever been around, they on average last decades.
As long as the refrigerant and oil is pure, often what “gets them” is moisture which turns into an acid.
For that reason, I second Pete’s recommendation of replacing the filter/ drier, and once the leak has been found having a very hard vacuum pulled and held overnight, you cannot pull too deep a vacuum, nor hold one for too long.

Price what two complete replacement systems would cost, you may be surprised.