NovaKool fridge freezer issue resolution

[suntansailor]

2000 390 MS Trawler; the fridge was just not cooling, and the freezer was just not freezing completely. Now understanding I live in the tropics, I thought about this awhile...then came up with a simple solution.

In the factory fridge vent above the stove, I installed 2 computer fans. A 12v DC wired to fridge control module, and 110v AC fan wired to the fridge 110v outlet. Now the hot air from the fridge is force ventilated out the normal vent, and I have picked up at least 30% more cooling efficiency.

The only bugger was pulling out that darn fridge/freezer to do the wiring.

Now with my 250w solar panel, when out on the hook the batteries stay topped up while running that fridge on 12v.

PS: still looking for any help on my FB wind deflector molds or original vendor as mine was damaged from Irma.

 

[Comodave]

I am installing a 12 vdc fan in mine. It hooks up to the controller board and only runs when the compressor is running. It draws 50 mAmps so it should save more than it uses. I have a Vitrifigo refer and it has terminals specifically for an external fan, don’t know about Novacool.

 

[suntansailor]

NovaKool additional exhaust fan

Spoke again to tech support at NovaKool, and he reminded me that the max amp draw I can have with the factory cooling fan, and my aux cooling fan is .5amp, otherwise compressor may shut down as an overload.

Hate this! Now I have to take that fridge out from the cabinets again, doors off, and see what the specs are on my new PC fan is, combined with that factory fan...to verify that I have not shot myself in the foot.

 

[Comodave]

We took our refer out yesterday and installed the fan. It come on and off with the compressor. It is freezing cold here so I don’t know what the results will be when we get to launch the boat. Good luck and have fun...

 

[Xsbank]

Use a relay,should lower the load.

 

[boathealer]

Spoke again to tech support at NovaKool, and he reminded me that the max amp draw I can have with the factory cooling fan, and my aux cooling fan is .5amp, otherwise compressor may shut down as an overload.

Hate this! Now I have to take that fridge out from the cabinets again, doors off, and see what the specs are on my new PC fan is, combined with that factory fan...to verify that I have not shot myself in the foot.

Those would be a couple of mighty computer fans to add up to half an amp. Should be more like 0.1-0.150A total.

 

[OldDan1943]

I stumbled upon a battery operated (D cell) fan to put into the fridge side. Battery i supposed to last 3 months.
I put it in the back right corner to keep the air stirred up around the thermostat

 

[kmbcpa]

Buy a new reefer....

 

[dhays]

Those would be a couple of mighty computer fans to add up to half an amp. Should be more like 0.1-0.150A total.

My thought as well. I bet those fans have very little draw. OTOH, you should be able to hunt up the specs on the fan through where you bought it, unless of course you just scavenged a fan from a dead computer case.

One of the many projects I want to do is improve the ventilation behind my fridge. I think I can do it without even using a fan, just have to drill the right holes in the right places without cutting or puncturing anything important.

 

[skipper724]

Nova Cool Refrigeration

My 2000 390 also had issues. I pulled the unit and the tech told me to disconnect the fan and try it. Works fine now with no fan attached!

 

[C lectric]

My 2000 390 also had issues. I pulled the unit and the tech told me to disconnect the fan and try it. Works fine now with no fan attached!

Did you look at the fan specs? Maybe it was drawing too much current and doing exactly what was warned about above. Maybe it was faulty. Good as they are they do goof up.
Check the specs and choose an appropriate fan. There are LOTS of them through people like Newark, Digikey and even your local electronics parts supply stores.

It should be easy to find a 3" to 4" unit that runs on 12V and draws no more than 150mA or 0.15A which is way below the fridge output max. of 0.5A [500mA].

I use these fans in my current installation, Novacool, and previous installation, Norcold, and they do help but of course only really noticeable in hot weather. But they will make a difference especially where natural ventilation is poor which is the case with many boats, not all.

 

[FlyWright]

When I installed my NK fridge, I spoke with a NK engineer about maximizing its cooling and efficiency. He told me to unmount the fridge fan from the unit, extend the wires and install it into a 4 inch hole cut into the side of the enclosure for additional venting. This allows the air to be sucked into the bottom opening, up the back and sides then out the upper side vent.

Works like a charm with only the original fan and no extra loads.

 

[C lectric]

When I installed my NK fridge, I spoke with a NK engineer about maximizing its cooling and efficiency. He told me to unmount the fridge fan from the unit, extend the wires and install it into a 4 inch hole cut into the side of the enclosure for additional venting. This allows the air to be sucked into the bottom opening, up the back and sides then out the upper side vent.

Works like a charm with only the original fan and no extra loads.

Missed that point here.
Yes the fan must be mounted so it blows outward at the top of cavity and an inlet is needed at the cavity bottom. Otherwise all the heated air trapped inside the cavity simply recirculates. If the fridge cannot get rid of that heat then at some point as the cavity air heats the fridge can no longer cool the food. The fridge will run but not cool.
The whole point is there must be a way to vent the heat the fridge removes from its interior and get rid of that heat to the outside, not just inside the fridge mounting cavity.
Some builders do a decent job of providing for natural venting but many do not.

 

[Comodave]

My boat had a vent from the factory, but it is on the side of the refer box and completely blocked by the side of the refer. I drilled a 5” hole on the bottom by the compressor covered it with a S/S grill. On the inside of that hole I mounted a fan blowing into the compartment at the bottom. The fan draws .050 amps. I then cut a rectangular hole in the top of the cabinet and covered it with another S/S grill. This should help the natural convection flow of the hot air to exit the cabinet.

 

[Dougcole]

Sorry to glom onto this thread, but it has me thinking about my own boat...a mainship 400. My fridge compartment has two vents, a small one in the side of the cabinet that opens up in the galley just above the stove, and a second larger one that vents from the rear bottom of the box to outside the cabin.

What would you guys think of installing a pair of 12V fans, one that sucks in through the small side vent and the second that exhausts out through the big vent to outside the boat?

I wouldn't even have to wire the fans into the fridge as the main panel is right there and I have an open breaker/switch. I could just turn them on and leave them on.

Any input to offer?

Thanks,

 

[Comodave]

If you don’t anchor out much it isn’t a problem having the fans run all the time. I just added a fan to mine last week. It is quite easy on my refer to add it to the panel so it only comes on with the compressor. I put the fan on the bottom blowing into the cabinet because it was the only place the fan would fit. I also added a vent top and bottom so I could get some natural air flow through the cabinet. A couple of S/S grills to cover the holes. My fan draws .050 amps so it is well within the .5 amp max from the circuit board. Check your refer specs and see if it has designated taps for a fan.

 

[Dougcole]

Thanks. We do anchor out quite a bit, but have plenty of house bank to handle a couple of fans. I don't have a manual on my fridge, so I'll have to do some research to see if it has fan hook ups.

Intriguing idea to me. Our fridge works OK, but the freezer is pretty much just an extension of the fridge, maybe 5 or 6 degrees cooler other than in the ice compartment. And we keep the fridge running on the coldest setting all the time, so I'd love to do some sort of mod that might gain me a few degrees.

I installed a drop in Webasto fridge/freezer up in the summer kitchen on the FB last year (most 400s have an electric grill there) which we love. But we got a power surge in the Bahamas last year and it fried the fan attached to the compressor. The fridge still cooled without the fan, but nowhere near as well. The fan on the FB fridge is exactly like the 12V computer fans I see on amazon. Heck, I may even buy one as a spare.

 

[Comodave]

I got our fan on Amazon.

 

[suntansailor]

NovaKool additional exhaust fan UPDATE

I ended up finding a local boat supply store (IWW) that sells the factory replacement Waeco (sp?) fans...12v 150ma, so used 3 of those...one replaced my dead factory fan, another positioned to cool compressor, and a third pointed upward to assist the hot air to rise to the vent at top of cabinet.

Made a tracking chart, and it looks like I am now able to lower fridge thermostat from 6 to 4 (7 being highest), while still having the fridge thermometer in the "sweet" range, and freezer now freezes ice cubes over night (never did that before).

The 3 fans each draw just 150 ma, so pleased that my 250w solar panel easily keeps up when anchored out or on the mooring. Pretty "cool" for a 18 year old NovaKool fridge. Now the Heineken's are really cold here in the tropics...

 

[Comodave]

Glad it is working out for you. Impressive gain in cooling.

 

[suntansailor]

Latest update on fridge cooling issue

In reading all these suggestions, it is apparent that many of us trawler owners experience the same issues with fridge ventilation. I own a Property Management company here on island with many staff specialists...I invited my reefer tech for a afternoon on the boat with a motive...he took the fridge out of the cabinet and made several suggestions...one I was very surprised on...he said you should not have a fan blowing on the compressor, as it needed to heat up the gas to go up to the cooling fins...so we took out that fan I installed in previous threads. Then he installed one of my low draw amp fans pointed upward to force the hot air towards the vent by the stove top. Then drilled a 4" hole as suggested by many on this thread for ventilation inbound from the side cabinet, and also one facing outward to salon (hidden with vented chrome covers) to draw cooler air into that backside of fridge.



The results amazed me...now my 18 year fridge sits at 4.5 on the dial (7 is max), cycling regularly, ice in freezer in 6-8 hrs (when before it had to be 18-24 hrs). Thank you all for the suggestions on resolving this common ventilation problem for increased fridge/freezer operation. Here in the tropics, ice cold Heineken's are just mandatory out on the water.

 

[OldDan1943]

Suntansailor, did you install additional insulation on the sides of the box too?

 

[suntansailor]

Insulation install

No, did not install any insulation. My tech guy had a cool instrument that measures temp on an long flexible wand. After what he did, and when we put it all back together in the cabinet, it showed 3-4 degrees cooler behind the fridge, so I think all the fans and ventilation holes seem to be working.

 

[OldDan1943]

No, did not install any insulation. My tech guy had a cool instrument that measures temp on an long flexible wand. After what he did, and when we put it all back together in the cabinet, it showed 3-4 degrees cooler behind the fridge, so I think all the fans and ventilation holes seem to be working.

Thanks.

 

[suntansailor]

NovaKool cooling update

Just wanted to share this update on improving the cooling efficiency of my NovaKool RFU6200 on my 2000 MS 390:

After the 3 fans installed (outlined on previous thread), I still was not content with the cooling, so went to the experts at NovaKool.

Spoke to Jim/Stuart and they were extremely helpful, not to mention full of knowledge with 20+ years with the company.

They suggested I replace the old style 1/2" foam insulation on the back side of the unit with new 3/4", and at the same time replace the plumbers putty that seals the foam to the metal casing of the fridge/freezer. The appliance store manager where I bought the foam piping also added his two cents, saying why not wrap the foam with the metallic shiny duct tape that air conditioning staff use to further insulate.

The results were just amazing...was able to lower the thermostat from 4 down to 3 (7 being the highest), in 6 hrs reached 18 degrees in freezer (where previously I had achieved 30 with three new fans installed), and fridge now is at 37 no problem. The unit cycles on off now, so using much less amp hours than before.

The project took just over 90 minutes, and so well worth the effort of renewing life back into a 1999 manufactured unit.

Pictures say it all, with before and after.

 

[OldDan1943]

My problem involves humidity inside the box allowing for frost build up.
Yes, I replaced the door seal, no noticeable effect. Tomorrow is 'defrost the fridge day'.

 

[FlyWright]

That's where the Fridge Optimizer can help. I'm saving my boat pennies to buy one.

https://stainlesslobster.com/fridge-optimizer

 

[OldDan1943]

That's where the Fridge Optimizer can help. I'm saving my boat pennies to buy one.

https://stainlesslobster.com/fridge-optimizer

It is necessary to inspect the entire fridge for air leaks into the box. Air leaks will be the biggest contributor to the humidity inside the box.

I have the 3/4 in foam insulation board and tape.
Upon recent recommendations, I will need plumber's clay and silver foil too.

Yup StainlessLobster waiting to be installed. Saving up installing it until I get the collector box and vent hose to remove the heat from the area behind the fridge. I think it will take all day to do all the modifications.

How do you feel about installing a fan inside the box?
Also, has the discussion of the tray 'in or out' been resolved?
Also, the placement of the temp sensor bulb in the main box?

Understand, I am living aboard so the door opening and closing is similar to that of a house fridge. That too is adding to the box humidity.

I will be leaving the boat for 2 months so I shall wait until I return to modify the fridge. It would be best to be onboard to monitor the fridge rather than install it and walk away for 2 months. Once I build confidence in all the modifications then, I will feel more confident with the 'system.'

 

[FlyWright]

Yup StainlessLobster waiting to be installed. Saving up installing it until I get the collector box and vent hose to remove the heat from the area behind the fridge. I think it will take all day to do all the modifications.

How do you feel about installing a fan inside the box?
Also, has the discussion of the tray 'in or out' been resolved?
Also, the placement of the temp sensor bulb in the main box?

I'll be watching for your review of the installation and operation efficiencies on this unit.

I referenced the engineer's recommendation for an exhaust fan (not intake fan) here on post 12. Vent in from the bottom and out at the top for my unit.

Trawler Forum - View Single Post - NovaKool fridge freezer issue resolution

If I had technical questions about the installation I'd call the company and ask. I bet they'd have good advice for you.