Refrigeration Couplers , sometimes cause trouble .

[Typhoon]

One of the most forgotten part of your refrigeration system is your couplers . Except when they fail ! Then you will know all about them .

What is a boat marine refrigeration system’s weakest link?

Regards John.

[Richard Kollmann]

John, You forget to mention that the brass solder on connectors you recommend still use troublesome O rings.

[a64pilot]

Richard, I assume you didn't read the article?
Seems he covered O rings pretty well I thought

[Typhoon]

Hi Richard .Good observation . If you take a close look at design the o ring is a moot point . When you tighten the coupler to the soldered on brass fitting it becomes a metal to metal seal . I tested these couplers with and without the o ring to 300 psi with no visible leakage or pressure loss.

Regards John

[masonc]

Originally Posted by ColdEh Marine

One of the most forgotten part of your refrigeration system is your couplers . Except when they fail ! Then you will know all about them .

What is a boat marine refrigeration system’s weakest link?

Regards John.

I removed mine, flared and brazed the pipes together. End of leak.

[Bill O]

The typical quick connect o-ring fittings with any of the newer modular refrigeration systems do make it easy for the initial install w/precharged components, but are eventually the Achilles heel of the system.

Here's a link to the Aeroquip couplers used in the ColdEh system, if you want couplers in your system.

Originally Posted by masonc

I removed mine, flared and brazed the pipes together. End of leak.

I'll second the removal of the fittings, especially if you have to change the o-rings and evacuate the whole system (like the small o-rings in a Frigoboat system after they start leaking).

Cheers,
Bill O.

[JstaRebel]

Has anyone ever replaced the couplers / O ring fittings with Swedgelock fittings? They are what I used for my connections and even went as far as connecting a Swedgelock check valve for filling the system to reduce the soldering needs. Have not had any issues with them or even the nuts coming loose as I used Blue Block when tightening them. They were what I was worried about.

[Bill O]

Originally Posted by JstaRebel

Has anyone ever replaced the couplers / O ring fittings with Swedgelock fittings? They are what I used for my connections and even went as far as connecting a Swedgelock check valve for filling the system to reduce the soldering needs. Have not had any issues with them or even the nuts coming loose as I used Blue Block when tightening them. They were what I was worried about.

In my previous life as a scientist, we used Swagelok fittings on our analytical instruments for various gas supplies and they worked well. Usually a Loctite or other sealants are not needed, but may be warranted in a boat that will be subjected to large amounts of micro-vibrations.

If you are worried about them coming loose, possibly purchase a refrigerant sniffer to check your fittings as part of a scheduled maintenance check of the systems throughout the boat.

Bill O.

[JstaRebel]

Originally Posted by Bill O

In my previous life as a scientist, we used Swagelok fittings on our analytical instruments for various gas supplies and they worked well. Usually a Loctite or other sealants are not needed, but may be warranted in a boat that will be subjected to large amounts of micro-vibrations.

If you are worried about them coming loose, possibly purchase a refrigerant sniffer to check your fittings as part of a scheduled maintenance check of the systems throughout the boat.

Bill O.

I use the Swedgelock fittings on all of our high pressure SWRO systems, and never had an issue with them coming loose even with the extreme harmonic vibrations that come from the Desal plants. The Blue Block I used is thread sealer that actually gets hard. We heat it when needing to remove fittings sealed with the stuff. Haven't had an issue with anything coming loose on the fridge yet.

[Typhoon]

Originally Posted by masonc

I removed mine, flared and brazed the pipes together. End of leak.

I agree.

Having no couplers is the perfect world solution. I does make for a professional install only, and servicing a system very difficult.

I have these couplers on my own boat for years even though I could have soldered/brazed them together . They just makes things so much easer , I have never had an issue with them . Proper torque and cleanliness when installing them is the key. .

Regards John.

[Richard Kollmann]

Adler Barbour had the best leak proof refrigerant line connector with no O rings to leak metal to metal seal all the way. I built 25 units some years ago using John,s brake line connectors and after a time in service they would develop very difficult to find small leaks at o ring where copper line adapter was connected. Of the nine different types of refrigerant line connectors Aeroquip's teardrop or standard refrigerant flare nuts and a union are the only permanent leak proof connectors.

[masonc]

Originally Posted by ColdEh Marine

I agree.

Having no couplers is the perfect world solution. I does make for a professional install only, and servicing a system very difficult.

I received a new system, compressor, evaporator and thermostat, that had been installed. Customer brought it back to the store saying it would not work.
I took the compressor to my workshop and found a blocked copper pipe, factory error.
Rebrazed the pipes and installed in the boat. Vacuumed and added refrigerant.
System lost it's charge. Vacuumed and noticed it would not hold vacuum.
After messing around, realized it was the connectors. Cut them off, flared so one pipe fit inside the other, silver soldered with portable MAPP gas torch, vacuumed, it held vacuum. Left it overnight, filled with 134A, never had a moments trouble since.
I installed a digital temperature gauge, so now I can see precisely the temperature in the food area. I'd like to use as the thermostat but I don't know if that's a good idea. The normal thermostat is in contact with the evaporator, whereas the digital unit is hanging in the food area.

[Typhoon]

Originally Posted by Richard Kollmann

Adler Barbour had the best leak proof refrigerant line connector with no O rings to leak metal to metal seal all the way. I built 25 units some years ago using John,s brake line connectors and after a time in service they would develop very difficult to find small leaks at o ring where copper line adapter was connected. Of the nine different types of refrigerant line connectors Aeroquip's teardrop or standard refrigerant flare nuts and a union are the only permanent leak proof connectors.

Hi Richard .

These are not " brake line connectors"

http://www.suomenpikaliitin.fi/pages...Eaton_5400.pdf

And there is a metal to metal seal at the copper tubing/coupler connect point even without the O ring, these units seal.

They are designed for mobile refrigeration systems

Regards John.

[Richard Kollmann]

John check page 148 Items 2 and 12 O-rings in link you sent. These are the seals I found to be troublesome.

Also I always avoid suggesting soldering or Brazing 1/4 lines together as a DIY task, even professionals can screw this up.

[toddster8]

I had a devil of a time sourcing the couplers on Adler Barbour components that I put together. Then it turned out that the new ones were a different size than the ones I was trying to match. By the time I got out of that rabbit hole, the couplers cost more than the rest of the system! I felt pretty stupid, especially considering that i have a pretty good stock of swagelok connectors in the shop. Albeit not QDs.
BTW: I've heard that the original design spec for swagelok connectors was to withstand the vibration of a Saturn V rocket launch. I think they can handle a boat.