Freezer temperature too high

[Rich Stidger]

I have a h40.5 with a separate A-B unit for the freezer. This unit uses a cold plate for cooling. At the lowest temp setting and with no openings of the top lid, I can only achieve about +10 degrees F overnight. This temp is measured in the box about half-way down the cold plate.This is OK for keeping ice and foods that are previously frozen, but it will not keep ice cream. Bagels and bread products don't really freeze either. I have put a blanket of plastic bubble packing sheeting over the top of the contents and the the cold plate and that helps, but I am still no lower than +8 degrees.Shouldn't I be able to drive the box to zero degrees F?The box is located next to my refrigerator and is not near any heat source. I would like to think Hunter used enough high-quality insulation, but I really don't know.

 

[Rick D]

Same, Rich

I usually get about 10-18 degrees 6 inches down from the lid. Freezes better below, of course. All openings sealed. No gap in the gasket. drain plugged. Assume you have also sealed the gaps in the top of the compartment? It seems like it's insulated well (after tidying it up). Maybe it's a marginal unit for the size, it is pretty big, larger than a lot of ice boxes, anyhow. Boy, that was a lot of help, huh? Rick D.PS: Rich, I took the shelf off and hinged it. Makes it lots easier to get to the bottom of the freezer.

 

[Rich Stidger]

Rick, same as you.....

Your system mirrors mine exactly.I have thought of hinging the shelf too- just haven't done it. It's a tought spot to work in......What gaps in the top of the compartment are you referring to?

 

[Richard Kollmann]

Warm Boat Freezers

There are several areas to review in finding out why the freezer does not get as cold as you would like. After spending fifteen years in south Florida I have not found any production boats with freezers that will maintain temperatures below +10 degrees F.in the tropics, especially those with small 12 volt compressors. The first question asked when the temperatures in the box are not cold enough Is the compressor running continuously or is it cycling off and on? If a compressor runs continuously and the box isn’t getting cold enough, there is a lack of system Btu capacity or the other components lack the ability to transfer the heat from the box. The small exposed surface area of the power plate may not be able to transfer the heat in your freezer. The best freezers, even those with two opposing evaporator/holding plates, need air circulation around the outside of the product. In a small freezer with only one plate air movement is necessary across the plate. A small ½ inch wood rail that go across the bottom and continue up the box sides improves any boat’s freezer by natural tumbling of the air. Heat rises cold descends. A very small fan in the box will assist the movement of the air bringing the heat to the evaporator/ holding plate.If a refrigerated box does not reach the desired temperature because the thermostat is cycling the compressor off, the thermostat needs to be recalibrated. A simple test of the thermostat is to bypass its control for several hours. If the box gets colder, make sure that the thermostat is really a freezer thermostat then recalibrate it.

 

[Rick D]

Gaps

When I sealed the system, I used plumbers putty to seal the hole where the evaporator tubes ran through the forward part and the refrig tubes in the aft port side. Then I noticed I could feel a small gap at the top where the freezer sides meet the top portion. I inspected it with a mirror. I sealed those with silicone. That plus using the three-ridged insulation tape on the gasket mating surfaces, made the box cool down better and run much less. I think the next step, once I get the refrig compressor issues squared away is to add small computer fans to circulate the air in the refrig and freezer. I have one of those small battery powered ones, and it made quite a bit of difference. Time to wire some real ones in. Rick D.

 

[Rich Stidger]

I have already installed fans

Rick,I installed a fan in both the freezer and refrigerator after having a a battery powered on in the fridge. This is a very worthwhile project. The advantage is that the temperature is more even in all placed of the box. Items will still freeze next to the cold plate in the fridge, but other than that the temps are within 3-4 degrees everywhere.The fan in the freezer did not help to lower the temperature. I also sealed all the same spots that you mentioned. The freezer compressor does not run excessively- it is about the same duty cycle as the fridge.It is hard to tell precisely what the duty cycle is because the units run so quietly.

 

[Rick D]

Rich, Where Did You pick Up the Power?

I assume you followed the lines and went to the compressors for power? Rick D.

 

[Rich Stidger]

Fan Power

Yes, I picked up power for both fridge and freezer fan from the fridge power input. I ran two power lines, one to each compartment. The one to the fridge runs thru the freezer next to the refridgeration lines.The fridge fan runs 100% of the time if the fridge is powered on at the breaker switch panel. However on the freezer fan I wired a small toggle switch so that I could turn it off when I only run the fridge. Since I never run just the freezer, there was no need to put a switch on the fridge fan.I will be at my boat this weekend and I will take some pictures of both fans and post them on this message thread.

 

[Rich Stidger]

Here is the fan picture

I have three more pictures including the fan inthe freezer. If you want them I could post in the photo forum. They are close-ups of the fridge fan (posted with this message) and the freezer fan with switch.The picture here doesn't clearly show the vertical tube, but it is extended to about 1" off the bottom of the fridge floor. It picks up the coldest air and then blows it across to the opposing corner of the box. I used a 12v computer fan (about 60ma draw) and I modified the fan housing to fit inside of a 2" PVC plumbing elbow. The power cable is routed along the refrigerant lines to the compressor unit.

 

[Rick D]

Thanks, Rich.

Nice job. I've added it to the list. Rick D.

 

[Jim]

Easier Fan Installation

Rick - I did a much simpler installation in the freezer of my H450 and the results were fantastic. I attached a very small (2"?)laptop fan from radio shack to the wall fo the freezer just behind the holding plate using silicone aquarium glue (2-sided tape would probably work as well). It's angled at 45 deg so it blows warm air from the top of the box across the relatively protected back of the plate. I took power from the box lite, and replaced the plastic hold down latches with the newer brass ones.Mi installation isn't as pretty as Rich's but it made a HUGE difference in efficiency, I didn't lose any space freezer space and it only took about 20 minutes.Good luck!

 

[Rich Stidger]

What brass hold down latches?

Are there better latches than the plastic snap devices?