NOVA COOL FREEZER

[ice breaker]

I have a Hunter 2004 41AC. I have the Nova cool fridge and freezer. Refrigerator works great. Freezer has been problematic for 10 years. 6 years ago it developed a small leak in the evaporator plate, that was repaired. The system was evacuated and a new charge of 134a installed and adjusted per the factory instructions. With cabin temps in 75-80 range, and a secondary cooling fan installed, it will get no colder than 8F and will float up to about 20F before restarting the compressor. At these temp ranges it runs nearly 85% of the time.

My question is do other 41 owners see the same thing, or is this a lemon? given the integrated nature of the boat design, My only real option is to replace with the same unit....but I only want to do that if a new unit gives me the correct performance.

Thanks for your advice.

 

[ice breaker]

everyone must be out sailing....

 

[Ron20324]

everyone must be out sailing....

Not everyone is in your time zone. Some of us are still sleeping. Zzzzz

 

[jssailem]

Hi @ice breaker. I read your message on Wednesday. I assumed that you only wanted Hunter 41 owners to respond.

My question is do other 41 owners see the same thing

There have been a lot of innovations in refrigeration on boats in the past 14 years. If you want only a Hunter 41 answer I can understand.

 

[ice breaker]

The reason for the specific question is that nova kool still sells the exact unit that I have. I am willing to purchase a new one if I get better performance. So the real questions is: am I seeing normal performance or degraded performance? I am starting to believe that the repair some how reduced the efficiency of the unit, vs new condition.

Thanks again for your help!

 

[jssailem]

Which of their Novo Kool units was installed in your boat?

 

[ice breaker]

It is the f2600. 2.4cu ft. Front load.

 

[jssailem]

Ok. So the important element of the units is the compressor. Attached is the "Tech Page" of the Danfoss compressor used in the NOVOKOOL units. I have looked and the data for a 2004 unit did not come up in my search.
So you can create your own data. It would be more relevant.
Run the freezer. Record the energy consumption and the temp in the freezer. Here is a tool to measure the temp in the box. (AcuRite 00986M Refrigerator/Freezer Wireless Digital Thermometer )
Compare the power consumption to the data of the new units.

Performance is based on power used to temp maintained..You know and sound dissatisfied by the old unit. The data tells you what the new unit can do.

Beyond that it seems a SWAG (Scientific wild ass guess)

PS... My opinion is that all systems have weaknesses. The best possible compromise is accomplished when you bring frozen food to the boat and try to maintain the frozen state for as long as possible then eat the food.

 

[Twille]

I have a Hunter 38 with a Nova Cool Freezer. The biggest issue with these are keeping them full. They work great when full and over work when the contents are low. We freeze water bottles to take up the extra space, besides having ice cold water when we need some.

 

[Rick486]

I'm pretty sure we have the same 2 units on our boat. They are in their 12th year since new and both work fine. The freezer maintains 10 F, which is where I set it, and the fridge maintains 40 F. However, when we were taking possession of Maine at the dealers, the freezer didn't work at all and they replaced it with new.

 

[Boyd]

IB - I have a '05 41 AC and the exact same issue with the NK freezer. It hasn't worked since we purchased the boat a few years ago. Mine is the 1.9 and I've already pulled it once for service. It worked on the bench, but not so much when reinstalled at the boat. What did you end up doing? The obvious choice seems to buy the exact same model but they're expensive and obviously have some reliability issues. Also, no local dealer...

 

[ice breaker]

IB - I have a '05 41 AC and the exact same issue with the NK freezer. It hasn't worked since we purchased the boat a few years ago. Mine is the 1.9 and I've already pulled it once for service. It worked on the bench, but not so much when reinstalled at the boat. What did you end up doing? The obvious choice seems to buy the exact same model but they're expensive and obviously have some reliability issues. Also, no local dealer...

I gave up and did nothing. And I misspoke as we have the 1.9 just like you. The secondary fan has helped, but still frustrating performance.

 

[senang]

IB - I have a '05 41 ......... It worked on the bench, but not so much when reinstalled at the boat. What did you end up doing? ..........

If it worked on the bench and not in the boat there is something on the boat hampering its functioning.
Before you buy a new identical unit you can do 2 things to improve the situation. ( This is for my 2005 H38, your layout maybe different).
1. The NK freezer on my boat was running nearly continuously when loaded. I found out when in my bunk at night hearing it running. The solution was to improve air circulation at the back end of the fridge, there was no place the hot air could go. I did cut a hole in the side panel that separates the gimballed stove from the freezer. Initially I wanted to cut a hole upwards under the microwave, but the wood thickness and the coriander countertop made this an impossible complicated solution. I also repositioned the computer fan blowing air over the compressor and installed it in the newly cut hole, sucking the hot air out. Check also that there is an access for fresh into the space behind the freezer.
2. If solution 1 is not giving satisfactory results you can replace the thermostat with an electronic thermostat that gives you more control over the temperature in the NK fridge. You can find the STC1000 thermostat on fleebay, this unit is getting good press, I have bought it myself but it is not yet installed.
Search on the website Ocean Navigator for “Adding on electronic refrigerator thermostat”.

 

[lemoiney]

If it worked on the bench and not in the boat there is something on the boat hampering its functioning.
Before you buy a new identical unit you can do 2 things to improve the situation. ( This is for my 2005 H38, your layout maybe different).
1. The NK freezer on my boat was running nearly continuously when loaded. I found out when in my bunk at night hearing it running. The solution was to improve air circulation at the back end of the fridge, there was no place the hot air could go. I did cut a hole in the side panel that separates the gimballed stove from the freezer. Initially I wanted to cut a hole upwards under the microwave, but the wood thickness and the coriander countertop made this an impossible complicated solution. I also repositioned the computer fan blowing air over the compressor and installed it in the newly cut hole, sucking the hot air out. Check also that there is an access for fresh into the space behind the freezer.
2. If solution 1 is not giving satisfactory results you can replace the thermostat with an electronic thermostat that gives you more control over the temperature in the NK fridge. You can find the STC1000 thermostat on fleebay, this unit is getting good press, I have bought it myself but it is not yet installed.
Search on the website Ocean Navigator for “Adding on electronic refrigerator thermostat”.

1. was the solution for my fridge and freezer after speaking with NK. I called them to ask about recharging my units as they didn't stay cool enough in hotter humid days (30C 80%RH). NK asked me a few simple questions and confirmed my units were likely fine and suggested adding a second cooling fan and ensuring there was both an intake and exhaust vent for the back of the units. I was able to cut a 3" hole from the bilge to the back of the fridge and exhaust the hot air under the sink to behind the starboard hull. The freezer was easier as the back of the unit was open to the hull, so just needed to blow air across the compressor and coils with an added fan. Bought two 20mA 4" computer fans online and plugged them into the existing fan controllers. Could have gotten fancy and added a temperature sensor to turn on when outside temperature was over 25C, but decided the extra small amp draw was a small price to pay for simplicity and improved fridge and freezer performance. Since doing these upgrades, both units perform famously...Freezer says at or below -10C and fridge at 3C on the warmest days. NK said not to expect the freezer to get much colder than -12C to -14C. They still cycle frequently when the weather warms, but I blame that on the modest amount of insulation in the units. I'm still looking at how I could insulate them better without affecting access for service. Good luck.

 

[desodave]

Do you have any insulation around your fridge and freezer? My 38 had none and the best thing I did was to fit water resistant styrofoam insulation around the units - the kind you get from Home Depot to use under concrete. It took 1/2" everywhere except on one side of the fridge (beside the sink in my 38) - so I glued the insulation on the sink side of the wall - it's out of sight unless you really look hard. I also drilled a couple of holes to try to improve the airflow behind the units but wish I'd been a bit more aggressive. My water heater is under the settee directly in front of the fridge so I also insulated that with the same stuff. The performance improved considerably.