Cold Plate System Not Working

[Bustlebomb]

My previous boat had the standard 12V/110 refrigerator but the new vessel has a cold plate system and it doesn't seem to be working. I've never dealt with a cold plate system so this is all new to me.

As best I can tell, the system is a 110v, air cooled system. The compressor is a 134 unit by Copeland (I've attached a few photos below - sorry for the poor quality, I took them when I was just getting some numbers to look up on the internet).

When it is powered up, the compressor kicks in and it starts "cooling." By that, I mean that I can hear the compressor running. There are two copper lines coming out. One gets cool (not ice-cold) and the other gets warm (not hot) but the plate in the fridge seems to hover endlessly at 67 degrees (probably the temp in the insulated box), even when the system has run for a couple of hours.

There is a rotary temp control in the cabinet next to the box but playing with that doesn't seem to make a difference - I've set it at 40 degrees and at 10 degrees with no visible change in the temp of the plate. It does go higher and lower than that but I haven't tried to turn it down lower.

Do cold plates go "bad?" or do I need to get the system recharged? Is there an easy way to check? Are there any troubleshooting areas I can check myself before I get a professional involved?

Help please - the lack of cold beverages is making everything else on the boat much harder to troubleshoot!

Thanks,
Matt

 

[hollywood8118]

My previous boat had the standard 12V/110 refrigerator but the new vessel has a cold plate system and it doesn't seem to be working. I've never dealt with a cold plate system so this is all new to me.

As best I can tell, the system is a 110v, air cooled system. The compressor is a 134 unit by Copeland (I've attached a few photos below - sorry for the poor quality, I took them when I was just getting some numbers to look up on the internet).

When it is powered up, the compressor kicks in and it starts "cooling." By that, I mean that I can hear the compressor running. There are two copper lines coming out. One gets cool (not ice-cold) and the other gets warm (not hot) but the plate in the fridge seems to hover endlessly at 67 degrees (probably the temp in the insulated box), even when the system has run for a couple of hours.

There is a rotary temp control in the cabinet next to the box but playing with that doesn't seem to make a difference - I've set it at 40 degrees and at 10 degrees with no visible change in the temp of the plate. It does go higher and lower than that but I haven't tried to turn it down lower.

Do cold plates go "bad?" or do I need to get the system recharged? Is there an easy way to check? Are there any troubleshooting areas I can check myself before I get a professional involved?

Help please - the lack of cold beverages is making everything else on the boat much harder to troubleshoot!

Thanks,
Matt

I think with your limited knowledge of refer systems and lack of tools a call to a refer guy is in order. Spend time with the tech and ask questions to familiarize yourself with the system and ask questions. It sounds like a charge issue, the compressor is running, there is a temp difference between the high and low pressure sides, the superheat valve would also appear to be working. The refrigeration side is simple in execution.. if the charge is to low it will not pull much heat out of the plate.

HOLLYWOOD

 

[FF]

Sounds like a freon leak, and you are out of gas.

The Copeland is the very top of the line so a proper repair will give decades of service .

The tech will first find the leak, next he should install a new filter dryer , and them pump the system down and add freon.

In operation you will probably be able to hear a slight hiss in the feed pipe to the plate at the plate. That is normal.

Ask the tech if a sight class is installed (it should be ) and get to see it.IN operation you will see a mix of gas and liquid freon at start up and solid freon after a few min of operation.

Any bubbles while operating is low freon , time to call the tech back and find the leak.

When the system is working properly the larger line coming OUT of the cold plate will be frosting a bit for a foot or two.

The plate surface temp under operation , just before shut down will be 10-15 deg BELOW the plates eutetic rating .

Shoot the temp of the plate as it sits after a while to know its operating temperature , what the solution was set to.

A good sized compressor like a Copeland is a great way to help load the noisemaker to make it more efficient.

Hopefully it will also start on a 15A circuit , so cruising in poor electric areas the unit can run as required all night .

BEWARE if cruising in Mexico they sometimes do not use freon. A mix of propane and butane is actually more efficient than todays freon , but a leak in a diesel boat with non explosive vapor rated gear , fans . starter alternator , could be a problem.

 

[kulas44]

A simple check for low gas would be to just add a little 134 and watch the temp.

 

[Larry M]

How in love are you with the cold plate system? There are a lot of boaters who have or are trying to keep an old system a live. They ended up spending an equal amount of money trouble shooting/repairing an old system that they end up replacing any way. You can buy a 12 vdc compressor and evaporator plate for around $1K. Just a thought.

 

[FF]

You can buy a 12 vdc compressor and evaporator plate for around $1K. Just a thought.

And you can join the long list of folks with dead house batts or running a noisemaker to revive the batts.

Something has to be saved to enjoy refrigeration , battery power or frozen brine .

The advantage of DC is its cheap and a boat on the go may run the main engine long enough for a recharge. Dockside is easy.

One advantage of Eutetic (if the plate is large enough ) is its silent in operation , with no noise at night and no dead batts in the AM.

A second advantage of a well built system is it can save the energy , freeze brine, usually far faster than its safe to recharge batts.

This can be a nice hefty AC load for the noisemaker which will help it have a longer life .

For sailors the best deal was the York cast iron auto air cond compressor which would take a belt warming 10HPwhen just started.

The add was an hour a day , and the ice cream stayed frozen.

Sadly the Eutetic systems suffer from the same hassle as wet batts.

The LAST bit takes a long time.

Inside the eutetic plate the copper refrigerant coils get covered with ice .

Ice is an insulator so it takes longer and longer for the heat to be sucked from the far corners to freeze solution.

The cure is to press a set of refrigerant channels (4 or more) in a 2 layer copper plate then bend the copper panel to fit in the eutetic plate. This gives the least distance from the cold copper surface to the fluid .

Easy enough to have custom made but VERY expensive , and it would need to be done for multiple sized plates.

A compressor belted off a big noisemaker or the main engine that could handle the 10HP load could have refrigeration with perhaps 10-15 min of operation per day.

BUT how many would be willing to pay $1500 for each plate?

 

[Bustlebomb]

Thanks Larry, you bring up,a good point. I'm still trying to figure that out.

FF,
I agree with the load on the noisemaker and I love the idea of silence when on the hook. I understand how a cold plate functions in theory but, at the risk of sounding like a total idiot, I'm unsure how it will work for our use.

When the weekend hits, we'll cruise and either anchor out or grab a mooring can. During this, the refer will obviously be put to use as it is intended (power freezing the plate to act as a cold "reserve" for the reefer).

However, our boat sits at a dock about three miles from my house. As such, it is our after-work dock bbq place during the week. This means we'd love to have a fridge that stays on all the time to keep beverages cold, condiments at the ready, etc.

We want to have a fridge that is "ready to go" for both uses. The cold plate system is strictly 110v so I'd leave it plugged in at the dock.

Will it work this way? In other words, will the thermostat work to regulate temps at standard fridge temps to allow use as a "regular" reefer or is it designed to freeze the plate once or twice a day to maintain the reefer temp?

If left continuously hooked up to power, what temp do I set the thermostat at to make this happen?

The plate is installed in the box with a 8"-10" space above (freezer?) and the rest of the space below (reefer?). Does that sound right?

Sorry to sound clueless but, when it comes to this...I pretty much am.

Thanks,
Matt

 

[FF]

Yes it will work fine.

Some mfg will use a thermostat to operate the unit bit more common is a unit that measures the suction , which translates to temperature.

This is how much commercial refrigeration is done as the temps are lots more constant.

The unit also provides protection for the high side , a good built in safety feature.

The biggest hassle may be the operating noise from the unit if you sleep aboard..

Simply turn it off at night IF this becomes a problem. A larger unit like a Copeland is not as quiet as a house fridge , but its 10 times as fast.

 

[AussieCraig]

134 Copeland horsepower

I read the above with interest then went looking at these units online - they give specs that are either 'ton' or horsepower related...what 'tonnage' and or horsepower rating would be sufficient for a good sized cold plate system ?

 

[Giggitoni]

FF hit on it in post #3. Look for a sight glass or window in the coolant line. It's usually about 0.75-inch diameter. Turn the system on and look for bubbles zipping by in the glass. If the system is charged properly, you shouldn't see any bubbles. If that's the problem call a tech to recharge the system for you. AND, if that's the problem, I'll expect a cold beer when I visit! Good luck.

 

[FF]

Folks with a cold plate system , or just thinking of weather they would prefer to create and save cold rather than battery charge should get a copy of ,

Marine Refrigeration Guide Book, Selecting, Buying ...

Amazon.com: Online Shopping for Electronics, Apparel, Computers, Books, DVDs & moreMarine-Refrigeration.../B000GSS4RC‎Amazon.com


Marine Refrigeration Guide Book, Selecting, Buying, Installing & Servicing [Howard Crosby] on Amazon.com. *FREE* shipping on qualifying offers.

OF course like any book its sales are tipped towards THEIR system , but the selection ,install and trouble shooting work on any cold plate system.

It does not offer advice to KIT a home grown system , or build a reefer box , but the installation guide give a good idea and tables for heat gain with various sized boxes and various thickness of insulation.

For boats that wish to be independent for long periods of time this style of refrigeration ,must be considered.

But remember for it ( or any refrigeration) to work efficiently a good freezer box is required , none are OTS , you have to build one!!! And 4 to 6 inches of insulation turn a big area into a small area rapidly.

Lazy folks should look at Sun Frost in 12V or 120V as required.

 

[AussieCraig]

Ordered the book

I just ordered the book mentioned above, still curious re the 'tonnage' or horsepower of compressor required...?

 

[Giggitoni]

Matt mentioned that his system is air-cooled. Our Grunert cold plate system is water-cooled but runs three units in the boat; one freezer and two refrig. I don't know enough about them to understand the tonnage, etc. I'm going to watch this thread and learn something.

 

[FF]

12,000 BTUs is equal to 1 ton of refrigeration.

The usual large auto air cond compressor that would be belted to a drive engine or noisemaker ia about 20,000btu.

A fine big unit like a Copeland running on AC would be about 10,000btu.

The tiny 12v DC are about 2000btu.

IF you work out the BTU required per day for your box , it becomes fairly easy to figure how much power will be required to function.

Best is to get a big block of ice , put in your freezer chest and wait 2 days with out opening.

Then open it up and weigh the ice , return it to the chest and wait 24 or 48 hours.

Each pound of ice lost is 144 BTU.

This with some error will give the requirement in BTU that needs to be removed from your cold box every day.

If contemplating cold plates the capacity of the plates in BTU will let you decide how many hours or days the system can sit.

It is most efficient to have the numbers match 4 -5000btu plates would be great for an engine drive but poor for 12v

A 3000btu plate with a 10,000btu Copeland would also be a mismatch . 3 or even 4 would be fine.

The belt drive off an engine is the most efficient.

Running an alt, -50% to charge batts, -40% to then run an electric motor is worst.


However the 12V dc is easier to install, and boats have batts anyway.

And the cold plates do remove volume from the cold box.

 

[AussieCraig]

12,000 BTUs is equal to 1 ton of refrigeration.

The usual large auto air cond compressor that would be belted to a drive engine or noisemaker ia about 20,000btu.

A fine big unit like a Copeland running on AC would be about 10,000btu.

The tiny 12v DC are about 2000btu.

IF you work out the BTU required per day for your box , it becomes fairly easy to figure how much power will be required to function.

Best is to get a big block of ice , put in your freezer chest and wait 2 days with out opening.

Then open it up and weigh the ice , return it to the chest and wait 24 or 48 hours.

Each pound of ice lost is 144 BTU.

This with some error will give the requirement in BTU that needs to be removed from your cold box every day.

If contemplating cold plates the capacity of the plates in BTU will let you decide how many hours or days the system can sit.

It is most efficient to have the numbers match 4 -5000btu plates would be great for an engine drive but poor for 12v

A 3000btu plate with a 10,000btu Copeland would also be a mismatch . 3 or even 4 would be fine.

The belt drive off an engine is the most efficient.

Running an alt, -50% to charge batts, -40% to then run an electric motor is worst.


However the 12V dc is easier to install, and boats have batts anyway.

And the cold plates do remove volume from the cold box.

FF - You Sir are a champ ! Thankyou for your knowledge...

 

[Bustlebomb]

FF, you truly are a wealth of knowledge. I'll look into the book and also into someone to come and service the system.

It's threads like these that show the true value of trawlerforum.

Thanks again,

Matt

 

[BruceK]

FF, you truly are a wealth of knowledge. I'll look into the book and also into someone to come and service the system...
Matt

I second that.
The joy of eutectics: it gets refrigeration off the batteries. Big plus IMO.
Loss of gas says leak, that may not be good news. Cost 2K to replace my compressor unit, guy says it should last 10 yrs. I asked about an engine driven compressor as well as the 240v driven unit, he said they give trouble and not to. 2 friends with engine driven compressors are never 100% happy, my 240v powered unit does a good job for my fridge and separate freezer.
Nigel Calder has a good book on Refrigeration, theory takes some understanding. Getting an expert in is the right move. Here we now use a new atmosphere friendly gas which costs several hundred $ a kilo, part what it costs and part carbon tax the new Govt is trying to repeal.