refrigerator question

[Ingram Ranch]

i used to hear a fan blowing while the box ran.  not all the time. but a lot.  it is cooling now, about 3 days since i last heard it, but i am worried that the fan should come on some.  does anyone know if there should be a fan on some of the time.

[Ivan K]

If you have the Norcold refer, the fans get turned on as needed by a thermostatic switch at the top back corner of the box. If you are in a cold weather, it may not have activated yet.

[Ingram Ranch]

the fans still have not come on.  the box is cooling ok but,  when it gets more hot weather is this going to be a problem?

[Ivan K]

It would certainly effect cooling ability in hot weather,  especially with sun on that side. Unfortunately, unless the refer is on slide and you have a vent to get to the back top side of the box, it is hard to test or replace the temp switch without taking the fridge out of it's place. Same for replacing the fans if failed but there should be more than one fan. I don't remember where the fan power is coming from or whether there is a fuse for them in the black box at the back, you manual should show it. As a dirty workaround, rigging an auxiliary fan into the vent hole...

[96 EVO]

Are you talking about an internal fan, or external?

Which fridge model?

[Ingram Ranch]

extermal fans.  it is a norcold  double door 1200 series

Edited April 12, 2024 by Ingram Ranch

[Tom Cherry]

OK....again, this depends on the Referigerator.  BUT, the Norcold (all models) and the Dometics are the same.

There is a set of Cooling (Condensing?) fins at the top.  This is a long rectangular "module".  Pipe in on one side and out on the other.  There are thin fins that are stacked along the entire rectangle.

On the LEFT side...Dometic....maybe the same for Norcold, there is a small snap disk thermostat.  It is held in place by two small tapping screws.  There are TWO wires going to it.  It is the ON and OFF switch.  There SHOULD be 12 VDC coming in on one line....and the other goes through the thermostat switch....and to the fans.

The fans are BURIED somewhere in the bowels or the flue underneath the cooling coils.  Norcold has TWO as do Dometic.

These are small, very small, computer like fans.  They are 12 VDC. Many of us added supplemental exhaust fans to the roof vent....so when the thermostat kicks them on....they power 2 more...above....like an exhaust fan. 

NOW... Norcold and Dometic designed the cooling system more towards "Advertising BOONDOCKING life" than actually efficient cooling.  IF you are NOT boondocking...the the MORE air (the more fans as well as more powerful), the better....

NOW....there could be THREE ISSUES. 

No power to the Thermostat.  Maybe a FUSE.  Maybe on the board.  You need to test the wires.  ONE will have power (when the Refrigerator is ON)

Bad Thermostat - Norcold sells these....Amazon has them. Do NOT order a Dometic one.  The Norcold has a different temperature range.  It runs cooler or stays on MORE.  If you put in a Dometic, you will NOT have enough ON COOLING TIME.  I used a Norcold on my Dometic to improve the cooling.  THEY ALL ARE THE SAME Holes....

Bad FANS.  God HELP YOU. You can SHORT the two wires together....assuming you have power.  If the fans run....GREAT.  If they don't and you have verified 12 VDC to one wire...then start digging and you will have, I think, to remove the Norcold.  YOU CAN, if you have a roof vent....put in TWO fans (make a simple frame.  Many have done it.  @Dr4Film did this on his Windsor.)  PM him for some details or get his phone and call him.

That's it....

[96 EVO]

1 hour ago, Ingram Ranch said:

extermal fans.  it is a norcold  double door 1200 series

Is the fridge installed in a slide?

Operational fans are more important in slide installations.

[Ingram Ranch]

it is not in a slide.

[Tom Cherry]

11 minutes ago, Ingram Ranch said:

it is not in a slide.

We each have our own "knowledge and opinion" It is MUCH easier to put in additional exhaust (as in improved cooling) through a roof vent....as in the Norcold is NOT on a slide.  Many of us have jury rigged up additional cooling....that is why I fully understand HOW the system works and the controls...  RATHER than having to figure out HOW to get good exhaust.  The exterior, sidewall vent on a slide has several "air flow and thermodynamic" issues....which the roof vent does not. I'd consider myslef LUCKY it is NOT on a slide. Many of us have accomplished that and improved the cooling, marginally, and it was a PITA.

Having a simple roof vent where you can put in a few "greater" CFM fans and exhaust it up is much better...and if the fans are the issue, easier and more efficient.

Right not, I'd focus on WHAT the issue is...as in do the troubleshooting...  THEN formulate the best solution...

 

[Georgia Mike]

From what I remember the cooling fans get their power from the computer board that you can access from the outside. From there it goes up to the thermal switch that you can’t get to unless you pull the unit. I would check to make sure you have 12volts leaving the board and troubleshoot from there. As Tom said you could add fans at the top of the vent stack pulling air up wired to a on off switch to keep air flowing. From what I remember the fans ran most of the time unless you were in very cold weather. 
 

[Tom Cherry]

13 minutes ago, Georgia Mike said:

From what I remember the cooling fans get their power from the computer board that you can access from the outside. From there it goes up to the thermal switch that you can’t get to unless you pull the unit. I would check to make sure you have 12volts leaving the board and troubleshoot from there. As Tom said you could add fans at the top of the vent stack pulling air up wired to a on off switch to keep air flowing. From what I remember the fans ran most of the time unless you were in very cold weather. 
 

YES and NO.  The control board does not, as long as the refrigerator is ON and RUNNING, do any “controlling”.  There is a constant 12 VDC from the board that goes up to the Snap Disk Thermostat and that actually controls the fans.  So….operating in low temps….all ok.  No fans needed…..opposite for high.

There MAY be a thermistor in the circuit and goes to the control board and it will shut down if something is amiss to keep from damaging the cooling unit.

But the Upper Thermostat controls the fans to keep the “flue” or the air flow within a specific operating range…and that thermostat controls that.  I never remember NOT having voltage to the fan thermostat.  Pull the Norcold Manual….it tells all about it and how to test…

Again….from memory and lots of “experiments”.  BUT only the circuit and the manual will confirm.  Very specific procedures for trouble shooting.

The approach I laid out ASSUMES full time voltage….which I THINK is correct….

[Georgia Mike]

8 minutes ago, Tom Cherry said:

There is a constant 12 VDC from the board that goes up to the Snap Disk Thermostat and that actually controls the fans.

That’s what I said “ the fans get there power from the computer board and from there goes up to the thermal switch” or snap disk as you said.

[Tom Cherry]

2 hours ago, Georgia Mike said:

That’s what I said “ the fans get there power from the computer board and from there goes up to the thermal switch” or snap disk as you said.

Probably Semantics.  The fans are a “switched on” FUSED (I thnink) OUPUT  of the control board.  They are always ON or HOT when the refrigerator is running. The control board does not cycle them on or off or provide any “control” for the fans. The fin thermostat provides that.

[96 EVO]

Your best move if you plan on keeping the fridge till 'End of life', is to install an ARP Fridge Defend, along with one or two of their fans!

[rustykramermetalfab]

21 hours ago, 96 EVO said:

Your best move if you plan on keeping the fridge till 'End of life', is to install an ARP Fridge Defend, along with one or two of their fans!

I have a single fan Fridge defend for a 1200 Norcold, I no longer use. it was on mine for a short time. Cheap if someone is interested. 

[Ingram Ranch]

let me see what a Fridge defend is and i will get back to you.

[96 EVO]

1 hour ago, Ingram Ranch said:

let me see what a Fridge defend is and i will get back to you.

Well, I sleep better at night since installing one!

Wish I had purchased one when they first came out!

[Ingram Ranch]

how hard is it to install?

[rustykramermetalfab]

Not a big deal. Instructions are on line on their web site.  Just a few wires and a couple of sensors on the boiler tubes. 

 

[96 EVO]

Yeah I think I installed mine in 3 or 4 hours.

My Dometic fridge was a little more complicated install, as I had to install a relay so that the power for the defrost elements didn't go thru the Fridge Defend controller.

It was actually a good learning experience for me, as I'm not an electrical guy!

I learned about what relays are for, and have since installed a couple more fore other projects!

Edited April 17, 2024 by 96 EVO