Fridge troubleshooting - advice requested

[skipgundlach]

Originally Posted by chris in SG

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As for a more permanent solution, I'm hearing conflicting ideas here. I can avoid technicians if the addition of a "premade dryer with quick connects" is a likely solution, because this is a job I can do myself. I'm not going to attempt anything more ambitious..

Thanks again!

I lost my Frigoboat to contamination. I horribly regret not having a massive RFD (receiver filter drier) available as a plug-in to my system, as nearly certainly I'd still be using it today if I'd had that option. Instead I have a SeaFrost water-and-air cooled unit that for the 87 months I've had it, rarely doesn't either nearly double the amp consumption the Frigoboat keel-cooled unit I previously had used, or, including total disruption in the engine room to access the high and low side connectors to monitor what's happening, require endless fiddling and application, at the moment, of LOTS of 134a; I've ordered a sniffer to see if I can find the leak/s.

If I understand the previous post/s correctly, a large precharged RFD is available with the same quick-connects which you can use without losing charge, and get it into the system simply and quickly.

If it comes to that, a suction removal and proof-of-security (leave connected, with no suction, overnight and look at the gauge having not moved) of the refrigerant, and a recharge, should have you back in business, and a RFD capable of handling any moisture you might encounter.

Good luck!

[Richard Kollmann]

Chris, The chances are this problem has nothing to do with moisture or thermostat setting. I gave you a procedure to eliminate moisture as a problem by sticking your head in refrigerator box and listening to sound. If compressor is running and cooling stops the detected sound stops. If you keep compressor running minutes later the sound will return again as the ice melts. If melting ice restriction does not occur then you have contaminated oil. You can also identify and monitor refrigerant flow by changes an amperage to this system.

Buying Frigoboats very expensive quick connect filter is not lickely to trap contaminates. The filter you install needs to go between keel cooler and Cap tube evaporator. Your Frigoboat system is like a persons arteries when there are signs of blockage fix it now while you have a chance. I believe that a simple test now as to this blockage is it moisture freezing or contaminated oil.

If compressor and cooling stops and after compressor is left running and compressor stops problem may be a simple voltage or amperage problem detected by electronic module in order to prevent damage to compressor.

[Eder]

Originally Posted by skipgundlach

I.

If I understand the previous post/s correctly, a large precharged RFD is available with the same quick-connects which you can use without losing charge, and get it into the system simply and quickly.

!

Yes, I bought the part, I think it was $129 plus shipping. Coastal Climate Control has a handy video showing how to install it.


They really stressed not taking apart any lines or adding/removing any coolant. They said the coolant can produce a bit of moisture on its own, thawing out the unit with too high a heat can exacerbate the moisture problem. They have an excellent video how to thaw the frozen line as well.


At any rate I'm no tech, just relaying what has worked for me after years of freezing up every 2 weeks.

[Richard Kollmann]

Moisture can only interior refrigerant by mistakes people make or running compressor after there has been a major loss of refrigerant.

Frequent formation of frost in the refrigerated box that you refer to is the result of unwanted moist air infiltration.

No frost build in box means box thermostat is set to operate as a 50 degree F drink cooler or you have a automatic defrost refrigerator. There is no exception to the box not accumulating moisture in marine boating climates.

[Eder]

I'm referring to the fridge stopping cooling due to frozen moisture in the line, not the fridge box. Happened to me about every 2-3 weeks for a few years.

[RaymondR]

I would do everything I could to exclude electrical problems before opening the system.

A question for Richard.

Richard, how cold would you have to pull one of these small capillary units down to to get the low side into vacuum and how probable is it that if you did that an O ring leaked in air where it had not previously leaked all the refrigerant out?

[Richard Kollmann]

Eder, What indications do you have that cooling stops as a result of moisture freezing? If it is that compressor never stops running then it is a refrigerant flow restriction from moisture or contaminated oil. If you have a Frigoboat keel cooler system with the only one filter dryer mounted in return line adjacent to a hot compressor this might explain moisture freeze ups every 2 to 3 weeks. These small dryers holding only a few drops of moisture when exposed to heat will instead of holding moisture for ever, will when warm discharge it back into refrigerant flow. An old method of removing moisture from refrigerant was to cool filter dryer with ice prior to replacing it. Today with refrigerant oils that refuse to release moisture we use two stage vacuum pumps capable of drawing a vacuum of 25 microns, much greater than vacuums indicated on refrigerant gauge sets.

RaymondR, There are different applications for O ring type liquid seals Actual sliding seals like those used in hydraulic cylinders do leak and exposed in metal housings do leak in cold temperatures. Actual O ring seals require a controlled compressed pressure on both inner and outer surfaces so they are not desirable as a final seal in refrigerant lines. Compression O rings where seal is depressed greater than actual seals are commonly used in refrigerant lines but even they are life limiter. The best final seal materials for refrigerant lines are metal to metal seals. On pre-charged lines and equipment O rings are used to prevent leakage in making initial coupling of fittings together but when fitting are torque tight lifetime leak proof metal seals are the standard. Manufactures of these systems are able to solder refrigerant connection do to better quality control.

Raymond both cold and heat are likely to cause loss of refrigerant or infiltration air into refrigerant this is why metal to metal seals are the excepted standard in any refrigeration unit large or small.

[Eder]

Originally Posted by Richard Kollmann

Eder, What indications do you have that cooling stops as a result of moisture freezing? If it is that compressor never stops running then it is a refrigerant flow restriction from moisture or contaminated oil. If you have a Frigoboat keel cooler system with the only one filter dryer mounted in return line adjacent to a hot compressor this might explain moisture freeze ups every 2 to 3 weeks. .

This is the exact problem. The people at Coastal Climate Control sent me a dryer precharged with quick connect to install on the other line to solve this.As you know the quick connect uses an o ring...they don't recommend to touch or replace it unless the line needs to be disconnected anyway.


This is just stuff they told me over the phone on how to fix my fridge. Here in Hawaii theres no one that will or can work on Frigoboat, that's why I followed up with Veca to fix it myself.

[RaymondR]

Originally Posted by chris in SG

My Frigoboat front-loading fridge has a keel-cooler system. Recently the compressor started running continuously and the fridge was warm (negligible cooling) so I switched off the power, moved perishables into the freezer (separate system) and roughly one week later invited a technician onboard.

In the above the OP states that the unit was run as a fridge and it appears that it was run without any problems having been experienced previously. If so it appears highly unlikely that the evaporator was ever pulled down sufficiently to have pulled the low side into vacuum. This being the case it appears extremely unlikely that air and water would ever contaminate the system.

The technician asked me to switch on and a few minutes later the fridge started cooling. Aside from slight embarrassment, I was just thankful it worked.

In fact, it functioned normally for about one month after his visit. Now the same symptoms have re-occurred and I have just switched it off again - wondering if it 'needs a rest'. But seriously, this seems an unlikely intermittent fault. Does anyone recognize the symptoms or can anyone explain how the fridge was able to recover and function perfectly for a month without any action apart from resting it for one week?

In the above the OP states that "it functioned normally for about one month". So the moisture circulated in the refrigerant for a month without freezing then for some reason decided to freeze and form a blockage. Whilst this might appear possible, for example for some reason the system ran colder, it also appears unlikely as the moisture still had to get into a previously uncontaminated system.

[Coolerking]

As has been mentioned before, the last thing you do is mess with the refrigerant.
The first thing you do is make 110% sure that the power, wiring, fan if equipped and tstat are ok.
If the system has even a small leak, the the low side will, eventually, operate in a vacuum.
In fact, most of these systems are already operating at a very low pressure, the evap is usually running between 4 and 9 psi when saturated.

[OzeLouie]

Originally Posted by Coolerking

Did he add any refrigerant to it?
If so it's possible the O rings are leaking at the fittings.
As mentioned above, moisture will/can also cause intermittent issues.

Just a tip regards O ring replacement... check that O rings to be used are compatible with the refrigerant and compressor oil. Usually a Nitrate 70 type for R134a systems here in Aus, but not sure of the classification elsewhere, but important to use the correct type.

[Uncle Bob]

Originally Posted by OzeLouie

Just a tip regards O ring replacement... check that O rings to be used are compatible with the refrigerant and compressor oil. Usually a Nitrate 70 type for R134a systems here in Aus, but not sure of the classification elsewhere, but important to use the correct type.

Louie, a hearty welcome from another Aussie, somewhat north of you.

[Coolerking]

Originally Posted by OzeLouie

Just a tip regards O ring replacement... check that O rings to be used are compatible with the refrigerant and compressor oil. Usually a Nitrate 70 type for R134a systems here in Aus, but not sure of the classification elsewhere, but important to use the correct type.

POE oil is what we see here.

[Tupaia]

It is almost certainly the drier. Get someone to fit a bigger one, the standard ones are inadequate (CO2 cylinder size). I had same problem with my freezer after 8 years, fitted a small beer can size drier used in air con units 12 years ago. Same with fridge after 12 years that was 8 years ago. The pre-charged ones are probably only good for a new system yours already has a problem so needs to be evacuated. Make sure that the system is evacuated properly. Leave the vacuum pump running for at least 24 hours. Better still get the tech to start it on Friday evening and come on Monday morning to recharge. Don't over charge the pressures are stated but you need to check the runs from the compressor to the compartment to make sure they are not freezing up

[Richard Kollmann]

You must be careful when installing a larger filter dryer than the manufacture of system used. The system in this thread with a normal size evaporator contains around three ounces of refrigerant by weight. If a filter dryer the size of a beer can were used as a replacement on this system it would trap oil and lengthen time it takes to equal pressure differential before re-starting compressor. There are recommended larger filter dryers for these small systems and when used are mounted vertical with refrigerant flow indicator pointed down.