Bypassing fridge control board

[Pat]

Jim Dick:  You mentioned in another topic that you have learned to bypass your fridge control board.  How?  Why?  It was a major concern for me when my converter died the other day. 

What does the control board do? 

What other appliances have control boards and why?

--pat

 

[Jim Dick]

Pat,

Actually most of your appliances have control boards. The refer, hot water heater, furnace, etc. These are used to control the operation of each appliance.

The refer is cooled either by AC or LP. When one is having a problem with cooling it is hard to tell if the cooling unit is defective or the control board. Bypassing is done by turning off the power and disconnecting the AC leads to the heater element. By appying AC directly to those leads you can tell where the problem might lie. If your freezer gets to the 0 degree range then the cooling uint is probably OK. If it doesn't then the cooling unit needs replacing.

We have a Norcold 4 door refer. I disconnect the AC and turn off the refer. I then remove the AC leads to the heater that are attached to the control board. They are yellow and black, two each. Dometic refers may be a little different as to color and number.  I connect both yellow leads to one side of a power cable and the black to the other. Then I plug that into the outlet for the refer. The control board is now off and only the AC is attached to the leads. You won't have any ice maker operation and the light will be out in the refer. After several hours if the temp hasn't come down you'll probably have to replace the cooling unit. A note on Norcold 4 doors... you can do the same thing by disconnecting the connector at the light inside the refer. This is also the sensor to the control panel. That will force the refer into max cooling. I found that out after I went through the disconnect process several times!

In your case of losing power you can do the same thing to keep the refer cold. Just be careful when hooking up the power so you don't get shocked. It appears my problem is the fans. I now have the freezer at 0 with the control board in the circuit. I placed a fan at the access panel outside. Once I got the freezer down to temp I disconnected the direct AC input and inserted the control board. It has been maintaining near 0 for several hours. Guess I'll be talking to the techs about accessing the fans. Unfortunately it appears we have to remove the refer from the wall to get to them. Now you know why I hate to give up my part time job at the dealership. ;D ;D

Hope this didn't confuse anyone too much.

 

[Pat]

Jim:  Not the least bit confusing.  I have a plan.  All I need to do is keep making the monthly payments on my maintenance contract.  Actually, I had to have my Dometic replaced less than a month after the warranty ran out last year, so this one has a couple years warranty left.  Dometic kicked in half the cost of the new unit, because the problem was a manufacturing defect - a defective weld according to Chinook -  and the warranty had so recently expired.

What dealership where?

--pat

 

[Jim Dick]

Pat,

My maintenance contract ran out. I'm on my own so the shop really is a help when I have problems. I had the cooling unit replaced two years ago so I wasn't looking forward to that adventure again. Appears I won't have to at this point. Freezer is -3.3 degrees this morning. Time to turn up the temp a tad.

Now to get to those blinkin fans!!!

 

[Pat]

Jim:  I'm into my 4th year in my Chinook.  So far this summer the igniter in the furnace died, the converter died, the black holding tank valve stuck and had to be replaced, and I'm swapping out the kitchen faucet and adding a water filtration system.  The first three would have fallen under some kind of extended warranty, except that the only deductible I could afford is $500.  I guess the big things are covered.  Or better be.

--pat

 

[Jim Dick]

Pat,

We all hope the big things are covered but not always so. On original warranties they would be. One must read the fine print on extended warranties to see what really is covered. Folks here have had situations where one part failed but it took out other parts. The original failure was covered but the ensuing failures were not. Like a lot of things it's a big crap shoot and we hope we come out winners.

We're in our 5th year of ownership on our American Dream. Everything is on our dime now.

Good news is it appears the only problem with the refer is the fans. They are not running and I assume the thermostat has probably failed. The only problem is the unit must be removed from the wall to access the fans and thermostat. Luckily I'll have help to do that.

 

[Karl]

Jim,

I'm assuming (never a safe thing to do) you have the 1200 model and not to sound insulting, but did you check the 5A fuse on the board and for +12 on the white wire going to the motors?  I can ask stupid questions because I just (almost) did a stupid thing. Water heater wouldn't fire up so I was all ready to order a new control board. Removed a 5 contact connector and noticed that the green wire (ground) coming from it went to a screw which held the plastic board in place. Sure enough, it was loose and corroded. Cleaned it and gave it a new ground hole to screw into and a separate screw to mount the board. Fired right up. DUH! And a question: What in the world does the flapper heater do? (please don't say it heats the flapper :-\)

 

[Jim Dick]

Jim,

I'm assuming (never a safe thing to do) you have the 1200 model and not to sound insulting, but did you check the 5A fuse on the board and for +12 on the white wire going to the motors?  I can ask stupid questions because I just (almost) did a stupid thing. Water heater wouldn't fire up so I was all ready to order a new control board. Removed a 5 contact connector and noticed that the green wire (ground) coming from it went to a screw which held the plastic board in place. Sure enough, it was loose and corroded. Cleaned it and gave it a new ground hole to screw into and a separate screw to mount the board. Fired right up. DUH! And a question: What in the world does the flapper heater do? (please don't say it heats the flapper :-\)

Karl,

You assumed correctly this time. I have the 1200LRIM but only have 3A fuses. I did check them and also checked the terminal of the sense wire to be sure it wasn't a break in the board. Then I measured the resistance between the sense wire and the ground wire. Appears to be about 13Megohms. I'd say the thermostat is toast but I'm no expert.

Flapper heater is a new one on me. I'll have to ask tomorrow if I get called to work. Bad grounds are the majority of the electrical problems we find in RVs.

 

[Karl]

Jim,

Not sure what you mean by the sense wire, but the wires for the fans, thru the thermostat, are the 2 immediately to the right of connector P1 on the power board. If you measure 13meg's there, I agree that the thermostat is toast. Hard to imagine BOTH motors opening up :'( The parts list says the fuse is 5 amp, but typos and e/c's do happen.

 

[Jim Dick]

Karl,

In following the primitive diagram for the electrical wiring with my refer it shows what they call the sense lead going to the thermostat and then to the two fans. The ground wire comes from the other side of the fan. I took the two leads that were labled the same way on the board and checked continuity. I don't think the fans are necessarily bad but the thermostat is open thereby giving the huge reading. At least that's what I'm hoping!!!

You're right about mislabling. Another fuse is labeled as an 8 amp and I know the one in there certainly isn't.

 

[Karl]

Jim,

I sure hope that 'stat is easy to get to! It would take three men and a boy (he would have to fetch the beer) to move that beast away from the wall.

Good luck!!!   

 

[Jim Dick]

Jim,

I sure hope that 'stat is easy to get to! It would take three men and a boy (he would have to fetch the beer) to move that beast away from the wall.

Good luck!!!   

Karl,

The refer does have to be removed to get to the fans and tstat. Another advantage for me working at the dealership part time.