Understanding our Frigoboat system

[witzgall]

Hi all,

On our new to us boat, we have a Frigoboat keel cooled system. It was installed in 1998, and I have identified it as using a BD3 compressor. The Controller is Frigoboat, Type K 134a, it has a big receiver next to the compressor:



We have two boxes., The fridge is a front opening box, with less than optimal insulation, at least in the door. It has a single thick holding plate at the top of the box.

The freezer is under the aft berth, and has two thick holding plates.

When we first moved aboard, I turned the thermostat of the freezer off. We were getting a nice cold box, but the compressor was running continuously. I recently turned on the freezer, and it seems to be working well, but the compressor is still running continuously.


Last I checked, the refer box was set to "3", and the temp was about 30F. I only have one digital thermometer, so I have moved that to the freezer to see where that is.

I assume that this should not be running 24/7? What can I do?


Chris

[DeepFrz]

Probably not very helpful but...

The Corrs -What Can I Do (Clip) - YouTube

[SV THIRD DAY]

No but it was still good.....

[DeepFrz]

I'm glad you liked it Rich.
Perhaps this one would be more appropriate.

"What Can I Do?" by Paul Baloche - YouTube

With humble apologies to the OP, at least we are keeping the thread alive.

[SV THIRD DAY]

Just a question for you to help understand, when you say "running continually" can you say for how long because the initial start-up could take hours to both pull your holding plates down and pull the heat out of the Box. We get the calls from folks when they just start-up a Technautics CoolBlue holding plate systems, asking why it is still running after 4hrs of initial start-up, which is perfectly normal. Holding plates have an initial start-up draw to freeze the plates that is a bit longer than units with evaporators that just need to pull the heat out of the box.

Kollmann Marine

Head over to Richard's site which is just a must read by any boater with a refrigeration system aboard and I would strongly recommend his books on Marine Refrigeration to any cruiser. Knowing and understanding what you have is important and worth your time and energy. Richard is an active member here and hopefully he will drop by and comment. But you can also reach him through his website.

OH and DeepFrz...thanks for the second Video....nice.

[witzgall]

The compressor is in the engine compartment. We have been living on the boat and using the system for several weeks. First, at anchor, we were turning on and of via the breaker. Now that we are on shore power, we have left it on, and started using the freezer. The compressor is running every time I check it.

I just checked the temps in the freezer, and it was 21.9F. It is empty except for two chicken breasts. The thermostat was perhaps 1/2 way, it is hard to tell. I turned it "On" more, towards colder, perhaps 3/4, and we will see where it lands. It is a pretty big box, perhaps 5cu ft. but it will be hard to measure as it is an odd shape.

The compressor was running right now, with a nice layer off frost on the fridge plate, and the freezer must not have been calling for cold, as it clicked and refrigerant started flowing when I turned the thermostat to colder.

Chris

[colemj]

Originally Posted by witzgall

The compressor is running every time I check it.

That won't do - you could easily miss it being off and get tricked into thinking it is running all the time. Put an hour meter on it and actually measure the % of time it is running.

Mark

[Captain Bligh]

I would see if , after the system has been running a couple of days, if you could get the compressor to shut off by lowering the thermostats in each unit. If the compressor does not shut off by lowering the thermostats in each unit , you have a wiring problem. If it does shut off, you'll have to figure out what temperatures they are shutting off at. 30 deg F seems a little low for a fridge, but not that low. I am not sure what the target temp should be for a freezer (20 deg F?)

[witzgall]

I just turned both of the thermostats to off, and indeed, the compressor cycled off. So that is good news. I guess I just have to keep playing with the thermostats to see what works.
Whew, that is at least one system that we don't need to replace, at least for now.

I do think the freezer, which is under that part of the aft berth that I sleep on, needs better insulation. It look to be about 2.5 inches, and I think I could feel the cold coming up from it last night. Not what I want this winter!! I wonder if the thing was ever used, the laminate inside looks to be virtually unblemished. So perhaps I can re-insulate it from the inside, as I cannot imagine needing such a large freezer. Or at least the top surfaces ;>

I did get a chance to read some of Richards book, borrowed from a fellow cruiser. I also read some of Richard's posts on-line. It seems that the BD3 was a single speed compressor, and that it does not seem to be a less efficient compressor compared to the current danfoss units, when used on larger systems. I wonder if the digital "set the temp" type external displays would work, that would be very nice.

Chris

[colemj]

Originally Posted by witzgall

I wonder if the digital "set the temp" type external displays would work, that would be very nice.

Chris

I don't know why not. They provide the same functionality - turning the compressor on and off when set points are reached. Their only advantage is that you get to see the actual temp and can adjust the temp range between on and off.

Mark

[MarkJ]

. Understanding our Frigoboat system

Lol no one in the whole world can understand their frigoboat system. I think the mass confusion and need for multiple technicians (and numerous forum posts) has made Mr Frigoboat a friggin millionaire.


Mark

[Richard Kollmann]

witzgall, you have a very strange and unusual refrigeration system. Anyone would need to see the system before giving advice and the one picture is too dark to see detail. I can guess at the design of complete system but several pictures would be needed before giving advice.
My guess is with only one fixed speed BD3 compressor and two boxes there are also two expansion valves and two flow control solenoid valves. There should be an electrical box with maybe safety devices and two diodes inside.

A few Questions:
1. Approximant Size of boxes?
2. Is system air cooled or water cooled or keel cooler cooled?
3. To test and see if insulation is adequate do you have two inexpensive thermometer?
4. What is approx temperature of seawater and ambient air where the boat is.
5. Size and thickness of each plate?
6. Has anyone worked on this system sense you bought boat, If so what was do to it?

If you email me pictures there will be more questions and hopefully performance improvement tips.

[witzgall]

Richard,

Thank you for responding. I have tried to answer your questions below. I also uploaded two high-res photos to my google drive account, found here:

https://drive.google.com/folderview?...DA&usp=sharing


If you save each of the files to your computer, you can zoom in quite nicely.

Originally Posted by Richard Kollmann

witzgall, you have a very strange and unusual refrigeration system. Anyone would need to see the system before giving advice and the one picture is too dark to see detail. I can guess at the design of complete system but several pictures would be needed before giving advice.


My guess is with only one fixed speed BD3 compressor and two boxes there are also two expansion valves and two flow control solenoid valves. There should be an electrical box with maybe safety devices and two diodes inside.

--- Yes - one BD3, and four little devices that sound like you are describing. I do not see an additional electrical box, save the bd3 controller box.

A few Questions:
1. Approximant Size of boxes?

The fridge is about 6 cu ft, and the freezer is perhaps 5.5 cu feet?
2. Is system air cooled or water cooled or keel cooler cooled?

Keel cooled

3. To test and see if insulation is adequate do you have two inexpensive thermometer?

I have a freezer safe digital thermometer.


4. What is approx temperature of seawater and ambient air where the boat is.

I am in Annapolis, MD right now. Temp is perhaps 55f.


5. Size and thickness of each plate?

Fridge plate is approx 4inx11x11in
Frezzer plates are each 2inx16inx9in

6. Has anyone worked on this system sense you bought boat, If so what was do to it?

Nobody has worked fridge since installed, as far as I can tell.

If you email me pictures there will be more questions and hopefully performance improvement tips.

[Richard Kollmann]

I need two additional pictures of thermostat and Refrigerant expansion valves.
An electrical drawing would make it easier to understand how system is controlled. I would like to see a two to three day run of both thermostats set to very cold and then record box temperatures when compressor is stopped by thermostat. The picture of suction filter or maybe an accumulator appears to be frosted indicating one of the expansion valves is allowing too much liquid returning to compressor. If this frost just occurs in the first 15 minutes and disappears it may be a normal condition during system pump down. The two relays in pictures must have some purpose? `Another problem is what stops compressor if both solenoids close at the same time and compressor goes into a repeated restart mode?


You have a very interesting design but I can not make the math work unless boat remains in a cool climate and then compressor most runs all the time.
Your combined holding plates contain approximately 5 gallon of eutectic solution. To freeze that much solution even with keel cooler in 55 degree F seawater 5490 Btu of heat must be removed from solution ignoring heat from any other source. With BD3 compressor running at peak efficiency to maintain all plate’s internal temperature of +12 degrees F at a capacity of 300 Btu it will take compressor 18 hours just to freeze holding plates liquid solid.

With the refrigeration system capacity you presently have and adding heat load through even the best insulation and heat to remove from product refrigerated in box, I do not think boxes will ever reach a temperature to freeze much of the eutectic solution. My guess is when operating in warm climates the refrigerator box will be a good drink cooler and freezer a good refrigerator running most of the time.

I had a Hybrid system with the 12 volt side much like your system two boxes three holding plates. Drink cooler had a 4 gallon holding plate in a 4 cu ft box. Five cu ft Refrigerator/freezer had a 3 gallon and 1 gallon plate. The 12 volt system ran continuously while at the dock and my large engine drive refrigeration dad to run one hour per day when away from shore power to maintain desired box temperatures.

[witzgall]

Richard,

Thanks for following up with me. Of course, I am not thrilled at your assessment, as we were looking forward to having a good freezer for the first time. I am sure that the insulation, which is perhaps 2 inches except for the fridge door which is less, is original 1978. We could re-insulate much of the freezer from the inside without much difficulty. I have put some more photos up in the same place:

https://drive.google.com/folderview?...DA&usp=sharing

I can work on the electrical drawing.

When I checked the fridge temp this AM, it was 41F mid box, with the thermostat set halfway between 0 and 1. Freezer still had a rock solid chicken breast on the bottom.


Chris