Refrigeration

[BonesD]

Hello, I need some insight to my new (old)to me boat/refrigeration. Just replaced the compressor belt and charged up the system. There is a breaker that has to be turned on to energize the compressor clutch. Fridge goes down to 12 degrees Fahrenheit in about 30 minutes with the engine running. .
Is there any regulation? Boat notes say to run about 30 minutes a day to keep the the plates cold
And
Access to the box is removing a large plug, about half the counter space to access the inside. All seems a bit inconvenient or is just another learning curve. Thanks all

 

[DavidM]

It sounds like you have an engine driven holding plate system. As you suspect, some of these don't have a thermostat. You just run the engine enough to keep it cool inside.

This isn't necessarily a good system for engine health, if a lot of its hours are spent at or near idle running the fridge compressor. If this is how you use it, run the engine up near wot for 15 mintues at least once a week to burn out the carbon.

David

 

[gsholz]

We have an A/C powered holding plate system ( 2 refrigerators/1 freezer) with thermostats in each box. The system shuts off when all holding plates have reached their set temperature.

With an engine driven only holding plate system, how do you keep your stuff cold when in port? Or is there an A/C backup?

 

[tozz]

We have an A/C powered holding plate system ( 2 refrigerators/1 freezer) with thermostats in each box. The system shuts off when all holding plates have reached their set temperature.

With an engine driven only holding plate system, how do you keep your stuff cold when in port? Or is there an A/C backup?

We have a similar system. A Grunert. We do have to manage ice build up every few months.

 

[BruceK]

Engine driven compressors seem to do a faster job of pulling down eutectic/cold plate fridges and freezers than an electric compressor using shorepower or genset. My electric system has thermostats, seems your engine driven system does not, maybe see if you can add one.
The big plus of eutectics is they are not a load on your batteries. Interestingly, the temp in my fridge can drop another 2deg C after the compressor shuts off.

 

[BonesD]

I guess it will take some getting used to. I have been using a Yeti and a block of ice up to now as I slowly discover the devices on board. It gets down to 12 degrees on one side while the other is 20 degrees or so higher. I don’t like having to run the engine for so long doing nothing but chilling the icebox.

 

[BruceK]

I guess it will take some getting used to. I have been using a Yeti and a block of ice up to now as I slowly discover the devices on board. It gets down to 12 degrees on one side while the other is 20 degrees or so higher. I don’t like having to run the engine for so long doing nothing but chilling the icebox.

I asked about adding an engine driven compressor to my 240v compressor unit, the guy who would be doing the job said they cost and are not that reliable. If you had an electric compressor you`d likely run the genset an hour morning and evening to feed it, though you`d be doing other charging etc same time. Some days out you are doing a trip which does the fridge as well.
Give it time and explore options. We load an electric 12v/240v portable fridge at home, plug it in while driving to the marina, and when on the boat.
My eutectic system, serving both fridge and freezer, takes a much longer 3 hours to pull down from ambient,but we can leave it on, on shorepower, at the marina. That`s the thing you can`t do.

 

[FF]

Most engine driven eutetic plate do not have a thermometer as such because it has little value.

Instead they have a control box that senses the plate discharge suction. This is a better method of weather the entire cold plate is solidly frozen, the requirement for a eutetic system to function holding over. Just getting cold doesn't do it.

Our engine drive plate system holds frozen for 4 days , on 2 hours of engine operation.

In coastal cruising its pretty easy to head for another anchorage , 2 hours or more away every 3rd day or so.

We have been known to buoy our anchor set , and spend time motoring if we wanted to stay longer.

Zero time is spent running the engine with out a propulsion load.

We do have a thermometer to monitor the system, on freezing the box temp is -10f, what it takes to freeze a 0F deg plate and the box sits at +4F for the next 4 days.

Biggest hassle is the box is divided with a spill over device, to steal cold from freezer side to reefer side . The insulation works , but when freezing the freezer side the temps in the reefer side go way down. Removal to a plastic chest is required to no freeze vegis.

 

[BonesD]

Thanks for the info, I didn’t realize that the right side is a higher temperature that’s something. Access to the fridge is a pain. The whole top is a very closely fitted piece of ash. Heavy and tough to get in straight so that it goes completely in. It also tends to collect stuff since it’s a flat surface so it has to cleared before opening it.

 

[C lectric]

As said it is a eutectic plate system. They were the cats meow untill the Danfoss systems arrived.

They are still good systems and often prized by serious cruisers that are out for long periods needing minimal power use [having minimal battery power] except when the engine is being run which hopefully is when you are moving anyways.

Being the refridgeration expert that I am ***NOT**** I don't see a reason a T.stat could not be fitted to operate the clutch.

The stat would need to be wired to control a RELAY that would in turn control the clutch. The stat will not be able to handle the current of the clutch. The existing panel sw. could be left for emergency if the stat fails.

You would need to be able to disable the T.stat circuit if the engine is not running so the clutch remains inactive at those times or suffer the electrical draw..

An oil pressure switch would be a good means of control as the clutch would activate only when the engine was operating producing enough oil pressure to close the sw.

Just some thoughts.

 

[BonesD]

Last week I was trying to add a can of coolant to the system when the belt started to squeal. Loose belt and probably air in the system. Being alone instead of climbing out of the engine room and shutting the a/c or the engine off I just reached over and moved the throttle arm over like the solenoid would normally to kill the engine. I forgot about it til later that night when my phone wouldn’t charge because the batteries were depleted. The clutch on the compressor had been engaged all afternoon sucking down the power. Fortunately, nothing got hot and burned and the clutch seems to survived without any yet noticeable problems

 

[C lectric]

I would venture that the clutch won't really care as it will be designed CONTINUOUS DUTY
so whether it is actually driving something or not the coil could care less. The only concerns would be eventually some small amount of life will be lost and of course what happened to the battery.

 

[BonesD]

Welll the batteries are new and weren’t flat but limping. Just a good cycling.

 

[FF]

"I don't see a reason a T.stat could not be fitted to operate the clutch."

It could , but you would not know the temperature or time required to freeze ALL the eutetic solution.

The suction control does not guess, that's why its been used for at least 4 decades.