Converting Older AB Cold Machine from air to keel cooling

[zboss]

Folks,

Is it possible to convert our air cooled AB Cold Machine (anyones guess as to the age but it works) from air to keel cooled? If it is possible, what are the pros/cons vs. just getting a new unit?

Also, we appear to have a small circuit board across the P/T inputs on the danfross controller that has pins for 2000/2500/3000/3500. I am assuming that this is the fan speed. I want to convert from an old analog thermostat to an electronic PID thermostat (Carel or similar) but I do not know what impact that circuit board would have on the new Carel connections... should it be removed?

Kindest Regards,

- z

[colemj]

Anything is possible, and what you want to do can be done. However, it would be much less expensive to simply buy a new keel cooler unit than to do the conversion of your existing compressor.

Those numbers are compressor speed, not fan speed. They represent resistors added to give varying speeds.

Mark

[Doug Brown]

I found the simplest, fastest, cheapest way of getting the Cold Machine to work better is to replace the itsy-bitsy tiny cooling fan they have on the unit with a 6" Hella Cabin Fan.

An added plus is that the 6" Hella fan uses slightly less amperage than the fan that came on the unit.

You can install/position the Hella fan pretty much where ever you have the space so that it blows air over the cooling fins or the whole unit.

Try and make it so the Hella draws "cool" air from one compartment and it's airflow pushes the "hot" air into another compartment.

Takes more time figuring out where you want to mount the fan than actually mounting it. Simple two wire installation (cut old wires, crimp on new wires) and you don't have to dis-connect any of the refrigerant lines.

[a64pilot]

If you don't mind my stupid question as I have an old AB cold machine as well, but why do you want to do the conversion?

[colemj]

There must have been a change in the design of the AB Cold Machine in the past. Ours came with two 6" fans on it - one pulling air through the condensing coil and one pushing air through it. Both fans together draw less than an amp. There is a shroud around the coil with a duct that brings cool air from wherever you put the other end of the duct.

Mark

[Cheechako]

I've had a COld Machine that had both the fan and a pump cooler. The water cooler really had no advantage at all.... and was just more complication. It was setup up to run either way.
Try a bigger fan maybe. There are lot s of chassis fans that are quiet and cheap.

[colemj]

Yes, AB makes a dual cooled version. However, to retrofit the optional water cooling, one would pay more for the conversion (and potentially damage the system) than just buying a new keel cooled system altogether.

And the OP wanted a keel cooler, which is different than a water cooler.

Mark

[Cheechako]

Originally Posted by colemj

Yes, AB makes a dual cooled version. However, to retrofit the optional water cooling, one would pay more for the conversion (and potentially damage the system) than just buying a new keel cooled system altogether.

And the OP wanted a keel cooler, which is different than a water cooler.

Mark

Ahh,... right you are, I made the mental leap to water cooled.

[djmarchand]

If you want to save power then switch to a Frigoboat system. It is keel cooled with an external bronze condenser. It also has available a Smart Speed Control which learns how much cooling is needed and adjusts the compressor speed accordingly. Both of these reduce running current to about 3 amps and with 50% cycling gets total daily energy down to about 40 amp hours.

You could buy a Frigoboat keel cooler and solder it into your freon circuit bypassing the air cooled condenser. Then you will have to experiment with freon charging to get it right. And replace that little circuit board on the Danfoss with the Smart Speed Sensor. But I'll bet you will spend less on a Frigoboat system.

David

[Richard Kollmann]

Zboss, Yes you can install a keel cooler and balance system by setting the speed plate on terminals C and T to best daily energy consumption. The correct compressor speed will probably provide better satisfaction than shooting yourself in the foot with a keel cooler project gun. P terminal on control module is generally never used on boats as it raises the threshold for battery protection.

Why would you want to install a keel cooler on a CU100 or CU200 Adler Barbour?

[zboss]

Originally Posted by a64pilot

If you don't mind my stupid question as I have an old AB cold machine as well, but why do you want to do the conversion?

Amp utilization. The AB is in the engine compartment, since that is the only area we can put it. A keel cooler would allow us to keep the condenser in the engine area and get lower amp utilization, especially in the tropics. Right now, we are pulling between 8 and 9 amps when its running.

It runs less often on 3500 but draws more amps; it runs almost all the time if we are running at 2500 but draws lower amps when doing so. In the end, its a wash amp-wise.

In either case, we keep ice cream frozen.

We have the large evaporator/top load freezer, its the one that is 15"x6"x12" and it serves as a great freezer. I did not see one that large with the fridgoboat.

[a64pilot]

I asked as mine has the water pump conversion, but even without it I think it pulls less than 5 amps when it's on. I'm going by the DC ampmeter, I haven't gotten to using my inductive clamp on meter yet to see what everything draws, I'm no where near that advanced yet.
I wondered if you were trying to get better cooling or lower amp draw.

[zboss]

My wife and I have also talked about splitting the fridge and freezer in a spill-over configuration or maybe having two compressors - one for each side.

How much space can an air-cooled compressor freeze if the area is very well insulated... say, 6 inches all around?

[colemj]

We have a 4cf freezer spilling over to a 6cf reefer with 6" of insulation all around. A single BD50 air cooled compressor runs it using ~50Ahr/day. The unit runs 9-10 hrs/day in the deep tropics.

Mark

[zboss]

I measured the amp utilization via an amp clamp meter today.

At 2500 speed, the compressor uses 3.5 amps or so..
At 3000 speed it uses about 5.3 amps
At 3500 speed it uses 9 amps or so...