NovaKool fridge freezer issue resolution

suntansailor · 03-10-2018, 09:23 PM

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 · 03-11-2018, 12:26 AM

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 · 03-15-2018, 08:42 PM

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 · 03-15-2018, 08:55 PM

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 · 03-15-2018, 11:18 PM

Use a relay,should lower the load.

boathealer · 03-16-2018, 05:54 AM

Quote:

Originally Posted by suntansailor

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 · 03-16-2018, 07:55 AM

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 · 03-17-2018, 03:44 PM

Buy a new reefer....

dhays · 03-17-2018, 05:37 PM

Quote:

Originally Posted by boathealer

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 · 03-18-2018, 11:29 AM

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 · 03-18-2018, 11:49 AM

Quote:

Originally Posted by skipper724

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** · 03-18-2018, 12:13 PM

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 · 03-18-2018, 12:35 PM

Quote:

Originally Posted by 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.

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 · 03-18-2018, 04:50 PM

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 · 03-20-2018, 06:54 PM

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 · 03-20-2018, 07:47 PM

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 · 03-20-2018, 08:50 PM

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 · 03-20-2018, 09:20 PM

I got our fan on Amazon.

suntansailor · 03-28-2018, 07:51 PM

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 · 03-28-2018, 08:03 PM

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