Author Topic: Norcold adding fans (picture)  (Read 395 times)

Offline JohnM

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  • Year: 1987
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  • Model: Elandan
  • Chassis: GMC
  • Engine: 454
Norcold adding fans (picture)
« on: April 03, 2019, 03:12 PM »
See photo.


Norcold fridge. Not sure the model. Original, I think. I've cleaned the burner, everything works good, except on hot days the fridge doesn't work so well - normal, when there are no fans, so I hear.


Have some 12vdc brushless Panasonic fans, very very quiet, picked them up cheap, good air movers and low load.


Been looking at Amazon for PWM temp-controlled boards. Would put the temp sensor somewhere the coils get hot when the fridge is on, triggering the fans to run, both inside and out.


Something simpler, like a relay feeding off the existing fridge board.. is there a constant 12v source when the fridge burner is burning?


I've taken the covers off those units, the lower and upper (igniter), to clean out bugs, etc. They're in good shape.


See photo.

Offline Froggy1936

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Re: Norcold adding fans (picture)
« Reply #1 on: April 03, 2019, 05:34 PM »
I installed two 4 in computer fans And a switch with a piolet light  I just turn them on in the AM on hot days and off at night , Seems to work well freezer never goes above 0o and frige stay@ 40o  ! I also have a battery operated circulation fan in the fridge and i keep my beer in a cooler with freezer packs i rotate each AM From the freezer ! Soft drinks and chocolate also in the cooler !c   Frank
The Journey is the REWARD !

Offline JohnM

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  • Model: Elandan
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Project completed
« Reply #2 on: June 17, 2019, 12:09 PM »
See photos.

Instead of doing anything with your existing fridge wiring (the circuit I built in the photos), reducing build complexity, consider using a small solar panel on the roof, only to power the fridge fans directly. The fan & blower are needed more in the heat of the day, when it's sunny. HQST 12v 10w solar panel, Amazon B07L7Z2X4C. It will likely only run 1x of the Panaflow external fans (not 2x), and a small interior blower, Fugetek 12V DC Brushless Blower Cooling Fan, HT-07530D12, Amazon B00B2ARV22. Most people will be happy with the performance of one fan for the outside and one blower for the inside.

LP Gas triggered relay circuit:
You'll need a 'bosch-style' relay. Sold 4 for $10 on Amazon. B072QXDZRD.

The relay only draws milliamperes when running, so we are going to 'T' off the LP gas solenoid. If you use AC 110 instead, or are using your fridge on a variety of sources, different options are available: On AC 110, you can run the fan all the time, and simply 'y' the power for the fans off the main 12v DC circuit, without a relay. It might be possible to feed a fan trigger from the power board, but that's over the level of this how-to.

* There are fancier relays that are 'water resistant' and have heavier-gauge wire, but those don't get consistently good ratings.

You'll only need one relay, but I've used them for everything from an ignition-triggered kill switch for the headlights - only parking lights will turn on unless the ignition is in the ON position on the motorhome, and a UTV - so consider a box of them a good investment.

Also need: Some insulated spade and sleeve crimp connectors for both 12 gauge (yellow) and light gauge (blue). The heavy yellow crimps are kit Amazon # B074KD78VS. Also you will need some very heavy gauge (12 gauge, green and blue, about 6 inches of each). And some fine wire also (20-22 gauge, brown, again about 6-8 inches x 2). Also some green fine gauge wire (8 inches).

I encourage using high-temp rated wire for the heavy wire.

And one, or two, Panaflow fans model FBA12G12M (120cm, brushless, ebay $15 360420088138). Each are rated at 88CFM. Whether you need one or two depends on how hot the outside air temp is. One will be sufficient for most people. They are rated at about 6 watts, although I suspect they use a little less once running.

And some fuse holders B017BAF7GS (5 for $8, 12 gauge) and 3 amp fuses (5 for $3.50 B000COCAKC, or use more common 5amp fuses if you like risk).

JST connectors (low amp RC connectors, ebay $3.50 223518339188).

Or

PWM fan splitters for a desktop PC (amazon # B07C2W2CWB). Cut off the female ends (the ones that match the connector on the fan), leaving about an inch of wire on the female ends, and use the male ends with the rest of their wire, for adapters from your 12v circuit, to mate with the type of plug that comes on the Panaflow fans and blower. If the blower doesn't have any connector, you can use the female ends you cut-off.

Assembly:
Fine female spade connector onto a 'Y' of two wires: the black wire from the relay harness, and a fine wire (6 inches, brown). Other end of fine brown wire to an insulated male spade.

Fine female spade connector onto a 'Y' of two wires: the white wire from the relay harness, and a fine wire (6 inches, brown). Other end of fine brown wire to an insulated male spade.

Fold over and tape off the RED wire from the relay, we won't be using it, but it will be energized with several amps of 12v DC power when the relay is off, so we don't want it shorting to ground.

Blue wire from the relay: Connect it to the inline fuse holder, then the other end of the fuse-holder wire (usually orange), into one end of the 12gauge male insulated spade connector, jamming both the orange fuse-holder wire and the heavy blue wire into this connector (tricky).  The other end of the heavy blue wire: female insulated spade connector.

Green heavy wire: Connect it in a 'Y' with the fine green wire. One end of the 12gauge male insulated spade connector, jam both the fine green and the heavy green wire into this connector. The other end of the green wire: female insulated spade connector.

The fine green wire bare end (-) and relay yellow wire (+), connect to the JST or PWM insulated male connector, - and + appropriately.

Prep:
Shut off the fridge, and preferably pull the fuse for the fridge. Not the fuse for the DC heater behind the fridge - pull the fuse in the indoor RV cabin wiring panel. Unplug the fridge from 110AC, usually an outlet inside the inspection hatch. Power to the fridge should be completely dead, but if you have 3-way power, treat the DC 12v as 'live' when working on the fridge through the outside access panel.

Install:
Unplug the original wiring LP Gas solenoid female spade connectors from the solenoid, and plug them into your harness fine brown wire male connectors. Plug the female spade connectors from your harness brown wire (black and white wires from the relay), into the LP Gas solenoid. Now when the LP Gas is 'on' the relay will close.

Unplug the large (usually 8-10 gauge) green wire from the fridge power DC -12v. Carefully pull it out, and set it aside for a second. Plug your wiring harness heavy green female insulated spade connector into the fridge, replacing the original. Plug the original into the heavy green insulated male spade connector on your harness.

Repeat the step with the original BLACK wire to the fridge DC+12v, a heavy (8-10gauge) wire. Plug your wiring harness heavy blue wire into the fridge DC +12v jack, and plug the original black heavy wire into the insulated male spade connector on the heavy blue harness wire.

Mount and plug in your fan. I used some simpson tie galvanized metal to mount it with some screws. The 'open' side of the fan should be facing down.

Reinstall the fuse for the fridge in the RV. Turn on the fridge. Go outside and look: You should see the fridge flame is burning.

Finally, insert a 3amp fuse in your assembly fuseholder. If you did everything right, the fan should turn on. If not, a fuse will blow. Go inside and turn off the fridge with it's controls. The fan should turn off.

Turn the fridge back on, once you have verified it's working.

That covers the outer fan, and you should notice an improvement in the fridge. For adding the inner blower, use one of your other pieces from Amazon B07C2W2CWB PWM fan splitter connectors, to 'Y' the power to the outer fan and the inner blower.

Offline machias

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Re: Norcold adding fans (picture)
« Reply #3 on: June 21, 2019, 11:20 PM »

Norcold fridge ... except on hot days the fridge doesn't work so well - normal, when there are no fans, so I hear.

I replaced the original Norcold that died in our 1988 with a brand new 3-way. I was crushed to see it only "cooling" to 60 degrees on the first hot day.

I had been considering the Camco Solar Roof Vent but it was pricey, doesn't seem to have very good reviews, and it wouldn't be a drop-in because my roof steps down by the vent.

I'm working on re-sealing the roof and updating the old vents this summer, so I'm adding a fan for the fridge while I'm up there. I went with the Titan- 12V/ 24V DC 90mm - TTC-SC09TZ(A) from Amazon. It's half the price of the Camco solar with less work and more features. Clean looking controller that can operate manually or variable speed based on temperature, draws just under 1A at top speed, and the fans are rated for 7 years of continuous use. Even if they die, I should be able to easily solder in a couple of new ones.

Quote
is there a constant 12v source when the fridge burner is burning?

You can either piggyback off the existing 12VDC line for the fridge, or run a line from the closest source (light, fan) in the coach.

Best of luck, no matter which way you go!




 

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