Frigoboat freezer

[Typhoon]

You should be using a thermostat that connects to your evaporator plate , it is usually clipped on . It will control the compressor using evaporator temperature. These the thermostats that come standard with most capillary tube systems

If you control your compressor using box temperature , you run the risk of over powering your evaporator plate and the system not running as efficiently as intended .

Regards John Tully

[Sea Lyon]

Our Frigo Boat on Island Packet 370 is controlled by thermostat in back of boxes.John are you saying this is not a good idea? I can see how when unit is fully loaded the thermostat could not be seeing representative temp.

[leftbrainstuff]

Are your issues consistent or not?

The led suggestion wont help you diagnose refrigerant issues.

These systems are difficult to diagnose. The 'expert' advice is to not use gauges. After spending a year learning these systems and diagnosing loss of charge, a blocked evaporator and then a failed thermostat I fervently disagree. All 3 issues were not related. Probably more related to general component life.

The 'cutesy' self sealing fittings also suffer from oring creep compression. One poster wants to fit flared fittings. While this is a better engineering solution I suspect contamination issues would see veco face a great increase in warranty issues.

The potential for contaminants to be ingested is very high. I am pedantic about purging gauges and refrigerant. This is key to repairing these systems. I was fortunate that the previous owner had fitted both low and high pressure gauge fittings. Usually you only have a low pressure charge port and no way to connect a high pressure gauge.

I was experiencing an intermittent issue similar to yours. Ended up with 3 unrelated failure modes. First leaking fittings, then a blocked evaporator then a thermostat. All failed gradually or were intermittent which makes diagnosis very tedious.

The quality of many of the components are pretty average and seviceability is woeful for us cruisers in remote locations.

The capillary might have no moving parts which is elegant bit I would prefer better serviceability. Now I understand these systems I'll stick with them. Not sure they'd be my first choice for a new build. Their 12V consumption is relatively low which is nice.

For those 'experts' who wish to chastise my advice about using gauges then tough biccies. Good data beats subjective approaches every time.

[masonc]

I don't have any warranty.
I would prefer that if I am taking the system apart to flush the keel cooler anyway, I replace the connections with proper refrigeration connections and get rid of the o rings that are bound to fail anyway. Inert gas will prevent contamination.

[Typhoon]

Originally Posted by Sea Lyon

Our Frigo Boat on Island Packet 370 is controlled by thermostat in back of boxes.John are you saying this is not a good idea? I can see how when unit is fully loaded the thermostat could not be seeing representative temp.

Sorry for the thread drift .

You may have a sensor on the evaporator , as well as a temperature sensor in the box if you are using a digital thermostat.

Yes you should be controlling your compressor via evaporator temperatures .

Seafrost has a good manual for installing a digital thermostat .

http://www.seafrost.com/pdfs/ETT/ETT%20Manual%20pcb.pdf

Regards John Tully

[Typhoon]

Originally Posted by masonc

I don't have any warranty.
I would prefer that if I am taking the system apart to flush the keel cooler anyway, I replace the connections with proper refrigeration connections and get rid of the o rings that are bound to fail anyway. Inert gas will prevent contamination.

It is good that you have the tools (nitrogen) to do this job , Cost of getting a tech would almost certainly be more then then the cost of replacing the system.

Also will you be soldering or brazing ?

Also if you have an older Frigoboat , they improperly installed the filter drier on the suction side on some of there systems . You have to replace it any way so be sure you have it on the liquid line , or the side going to the evaporator plate

Regards John Tully

[Anna Sail]

Flushing the keel cooler, upside down or right side up, is frivolous and asking for trouble. The keel cooler is not a simple hose embedded in sintered bronze that you can flush like a radiator. It is an intricate component in a highly developed system.

Whether you use a digital thermostat that measures the temperature of the air in your box or a mechanical thermostat that attaches to your evaporator plate to measure the temperature of your plate makes no difference to the functioning of your box. Both act as an on/off switch for your compressor. That's it. That a digital thermostat will also act as a thermometer is an added bonus, giving you more control because you can see what your box temperature is at any given moment. A mechanical thermostat is less costly, however, it may reach end-of-life sooner, being more often subjected to the moist conditions of your box - be it a refrigerator or freezer box.

The original query here was a keel cooled system not always coming down to the set point. The first suggestion was that the system is under-charged, despite the fact that the plate is completely covered with frost - an indication of a fully charged system. The question to ask: when the system is not coming down to temp, and the compressor is running, can you hear refrigerant flowing into the evaporator plate? I have found the link below very helpful:

http://www.coastalclimatecontrol.com...%20Diagram.pdf

Hope this helps.

[Kenomac]

Originally Posted by Sea Lyon

Kenomac thanks for quick reply. Low refrigerant sounds very reasonable. I had considered it, the fridgoboat trouble shooting guide says that with evaporator fully covered in frost refregerent level is ok. But I don't really have a idea what else could cause it.

Has any one had any experience with refrigeration guys at George Town Bahmmas?

We had the exact same issue with two of our Frigoboat systems which drove us nuts for two years. Finally found a competent Frigo guy in Italy (Frigoboat is Italian) who diagnosed the problem in about ten seconds, then repaired it in a half hour for €100 which included flushing the old coolant with a vaccum pump and replacing the coolant with new. He first came aboard with two replacement "O" rings and said "this is the first place I always look."

You can try all the other nonsense first..... but you have a failed "O" ring. Your compressor runs all the time because there's not enough coolant cirrculating which also frosts up the evaporator. With sufficient coolant, your evaporator won't frost up as much because it provides a quick blast of cold, then shuts off. With it running all the time, it just continues to frost up.

Good luck.

[CarlF]

My last boat had a Frigoboat system with temperature sensor on the evaporator but the fancy MKII digital thermostat from Frigoboat on my currrent boat seems to use only a box temperature probe. I don't see anything on the evaporator nor does the manual mention anything but a box probe. It works better at keeping a steady box temperature than my old one.'

[Typhoon]

Originally Posted by CarlF

My last boat had a Frigoboat system with temperature sensor on the evaporator but the fancy MKII digital thermostat from Frigoboat on my currrent boat seems to use only a box temperature probe. I don't see anything on the evaporator nor does the manual mention anything but a box probe. It works better at keeping a steady box temperature than my old one.'

At High heat loads an electronic control is not a problem , all flashing of the refrigerant occurs inside the evaporator plate and very high superheat levels are common. The problem is when there is low heat loads, 100 percent saturated vapor, in the evaporator, may climb down the suction tubing. If a cap tube system is overcharged, it will back up the excess liquid into the condenser, causing high head pressures, it may even slug the compressor. This throws the system out of balance and it runs inefficiently and possible damage may occur. With the sensor being on the plate, the thermostat will simply turn off the compressor when full flashing has occurred and brought the evaporator temperature down to the set point.

Regards John Tully

[onavegador]

Years ago I had also a Frigoboat System. In the system was a (humidity) filter incorporated who has to be replaced in the tropics and near tropics about every six month. If not the system stopped cooling after a few minutes.
For replacing this filter I had to call a technician who also controlled the gas level and adjusted it.

The system needed just that maintenance and worked so far for three years of non stop use, after I sold the boat.

Good luck
James

[SV THIRD DAY]

Originally Posted by ColdEh Marine

At High heat loads an electronic control is not a problem , all flashing of the refrigerant occurs inside the evaporator plate and very high superheat levels are common. The problem is when there is low heat loads, 100 percent saturated vapor, in the evaporator, may climb down the suction tubing. If a cap tube system is overcharged, it will back up the excess liquid into the condenser, causing high head pressures, it may even slug the compressor. This throws the system out of balance and it runs inefficiently and possible damage may occur. With the sensor being on the plate, the thermostat will simply turn off the compressor when full flashing has occurred and brought the evaporator temperature down to the set point.

Regards John Tully

Anecdotal stories isn't the same as engineering testing.

Here's the honest and frank problem John...you are giving advice (as I do) from a refrigeration tech school perspective while others are playing the "it works for me" school. The problem is that their "works for me" advice doesn't understand the risks or that in some instances you can swim in a shark tank and not get bit while in others you end up missing a leg. The "Mine works" dock rumors and myths become true and you might as well stop banging your head against the wall.

Proper capillary evaporation plate design/efficiency is to have the thermostat measuring the evaporator temp and not the Box temp...if people don't want to understand or believe then you just have to at least bust the myth so others won't be sucked in and move on...at least that's my advice from one refrigeration guy to another...

[Sea Lyon]

Originally Posted by Kenomac

We had the exact same issue with two of our Frigoboat systems which drove us nuts for two years. Finally found a competent Frigo guy in Italy (Frigoboat is Italian) who diagnosed the problem in about ten seconds, then repaired it in a half hour for €100 which included flushing the old coolant with a vaccum pump and replacing the coolant with new. He first came aboard with two replacement "O" rings and said "this is the first place I always look."

You can try all the other nonsense first..... but you have a failed "O" ring. Your compressor runs all the time because there's not enough coolant cirrculating which also frosts up the evaporator. With sufficient coolant, your evaporator won't frost up as much because it provides a quick blast of cold, then shuts off. With it running all the time, it just continues to frost up.

Good luck.

Thanks for advice. I believe you are correct. As i mentioned above we switched boxes /systems the old refrigerator system must have a better charge. Now that we are using it as freezer its cycling and probably on less than 50 percent of time.

Old freezer is making it ok as refrigerator, its not running much at all. I suspect insulation between boxes is weak. Therefore getting some refrigerator cooling from freezer. At any rate we are hoping to make it till in range of known Fridge Boat guy.

[Typhoon]

Originally Posted by SV THIRD DAY

Anecdotal stories isn't the same as engineering testing.

Here's the honest and frank problem John...you are giving advice (as I do) from a refrigeration tech school perspective while others are playing the "it works for me" school. The problem is that their "works for me" advice doesn't understand the risks or that in some instances you can swim in a shark tank and not get bit while in others you end up missing a leg. The "Mine works" dock rumors and myths become true and you might as well stop banging your head against the wall.

Proper capillary evaporation plate design/efficiency is to have the thermostat measuring the evaporator temp and not the Box temp...if people don't want to understand or believe then you just have to at least bust the myth so others won't be sucked in and move on...at least that's my advice from one refrigeration guy to another...

Hey Rich . How you doing .

Yes , you are right , maybe I should just bite my tongue , and not get drawn into the conversation . But you know how it is ..... they ask .

Regards

[masonc]

Originally Posted by ColdEh Marine

Remember not to control your compressor with a box temperature thermostat

I got time to look carefully at the installation on our boat, the thermostat sensor is attached physically to the evaporator. All good.
Has anyone cured the keel cooler oil slugging issue without replacing the keel cooler? I'm thinking to make up adaptors, disconnect the keel cooler and blow a lot of air through it for some time to flush the oil. It would be much more effective if the cooler was inverted but that is not possible until we haul in hurricane season. I need to fix this now.