Super Cold machine Frosting up with pump running

[Ohanakai]

Hello I built and installed a freezer last season with A super cold machine without the water pump last season and all ran fine... This year we are heading for warmer climates and so I installed the pump sytem and have noticed my refrigerant line frosting up... I turn off the pump and the frost goes away and the system seams to operate better.... Is this do to the colder climate Im in and will it work properly when im someplace warmer or do I have another problem like to much refrigerant or something...

thanks

[Saorsa]

It sounds more like too little refrigerant. Get a refrigeration (or air conditioning) repairman to come and check the coolant and pressure.

If there is too little refrigerant, it pumps air along with it and doesn't run enough coolant through the lines. As a result, instead of moving quickly and cooling the refrigerator, it stays near the pump and cools the line.

It will also run longer. When you turn it off, the coolant settles to the lowest point (around the pump) and when you first turn it on it pumps coolant until it starts back pumping air.

[Ohanakai]

Hmmm... Did I mention in the previous post that the system works perfectly when the Cooling (seawater)pump is off and only frosts up when the pump is on? The evaporator plate is seams to be frosted over evenly all the way down so I thought their was enough coolant in the system? Is my logic flawed?

[Richard Kollmann]

Ohanakai, You have discovered one of the problems with water cooling one of these small refrigeration units. By changing the condensing cooling temperature the refrigerant charge and the system’s efficiency will vary. For that system to operate efficiently the evaporator must have frost over 100% of its surface and no frost outside the refrigerated area. Under the climate and water conditions you are operating in your system is over charged, when the frost line extends very far outside the box. With that unit you will find it is generally more efficient without the pump running.

For more info on this you may want to read FAQ #33 on my web site at,
http://www.kollmann-marine.com

From the author of four books on boat refrigeration

[Anonymous]

thanks for the great info

[dick foster]

does the same thing in cool weather if the salt water collant pump is on. I think the manual says the salt water coolant pump begins to save more energy than it uses when the temp around the compressor goes above 90 deg F. In hot weather with the salt water pump on, or in cooler weather with the pump off, I've never experienced a frost problem.

[Richard Kollmann]

Dick Foster is only correct when the seawater temperature remains between 55° and 75° F. at all other times the unit is less efficient.