Monday, October 17, 2016

Old RV Fridge Problem and Solution - Norcold 8663

Note: this post was originally created in 2014, but has been significantly updated. This advice will be of interest to anyone with an old RV fridge that is not working properly. Unlike the compressor fridge in your house, evaporation fridges (typically used in RVs) require consistent annual maintenance.

The fridge in my motorhome is a Norcold 8663. This is a 3-way model, meaning it can operate on:
  1. Propane (requires 12V DC ignition)
  2. Shore power (plugged in at a campground) or
  3. 12V only (for brief periods such as when in transit)
The model on the serial number sticker is is 8663, but repair manuals also use the number 866.  Here is an example of a repair manual: Norcold 86 series Service manual (823KB)

The Problem: At first, I would find the fridge dead by morning and would require several attempts to re-ignite the burner. The problem could be solved initially with servicing as described in the second half of this blog post. However over the ensuing years the problem gradually got worse and eventually no amount of servicing would fix it.

Here's a story of similar symptoms described in 1999 by Dave and Helen Damouth at:

"Ever since we acquired our 1988 trailer, three years ago, the Norcold model 8663 refrigerator has sporadically refused to operate on propane. Usually, the problem was that the flame would light, appear to burn normally, then go out after 10 seconds or so, refusing to start again until I cycled the control panel switch to "off" and then back to propane. In recent months, there has also been another failure mode, where the flame came on very weakly or not at all, and then blew out with a loud "pop".
Each time it failed, I did all the standard maintenance things, and it generally started operating just fine. Then, a few months later, it would fail again."

My solution is similar to theirs, but I have a few additional notes and observations.

The main problem was the ignition module, although annual fridge maintenance is always important with an evaporation fridge.

Here is a link to the Dinosaur website showing their various Universal Ignition boards, and  here is a link to Dinosaur Ignition Module UIBS that I purchased on, and here is a link to the cover. Installing this ignition module restored the fridge to correct operation.  I believe that the UIBL (large) ignition module may have fit better, so be careful to measure before you order. I am not certain.  I was able to make the UIBS fit, by drilling some additional holes in the metal panel that the ignition module mounts onto.  Other than that, installation was fairly easy.

Old ignition module

I believe that the old ignition module, pictured above, may have been replaced by the previous owner at some time in the past.  Note that the module is only mounted with two screws, and the one in the top left has a metal S bracket because the hole on the module does not match up with the hole on the mounting plate behind it.

New ignition module from Dinosaur Electronics
The new module from Dinosaur Electronics is universal and designed for furnaces and water heaters as well.  Therefore it is important to follow the enclosed directions to cut a jumper on the circuit board which is intended only for furnaces.  The jumper creates a 30 second delay, which is not required (and an annoyance) when this circuit board is installed in a fridge.

Another Observation:
You might also want to replace the ignition/sensing electrode as well.

On early Norcold fridges, there were two electrodes; a sensing electrode (thermocouple) and an ignition electrode.

Sensing electrode AKA thermocouple
Spark Electrode
I was able to purchase an ignition/sensing electrode at my local RV dealer because it is a fairly universal part, but was told that they could not order a separate spark electrode.
Norcold Ignition/Sensing Electrode
Just guessing here, but I assume at some point in the past Norcold combined the sensing electrode (thermocouple) and ignition electrode into one.

If you replace this ignition electrode with a new ignition/sensing electrode, but also leave the old sensing electrode (thermocouple) in place, it is unnecessary. I suspect that this redundancy may have contributed to my problems in the past.  I removed the old sensing electrode and the fridge works flawlessly with only the single ignition/sensing electrode.

Annual Cleaning

To recap, here are some pictures of an annual fridge cleaning, plus replacement of the electrodes (optional).

Fridge wiring

Wiring close-up

Wiring from the ignition module to the two electrodes

Remove the evaporation cup

Clean out the cup

Remove the drip tray

Expose the drip tube

Blow out the drip tube with compressed air

Remove the cumbustion chamber cowling

Remove the old ignition electrode to clean or replace

Remove the sensing electrode (thermocouple) to clean or replace
In this example the sensing and ignition electrodes are being being replaced with a single ignition/sensing electrode, in the same opening as the old thermocouple. Replacement of electrodes is NOT something you would need to do on a regular basis.  If you are re-using the old electrodes, they should be cleaned as a part of the annual servicing because they can corrode or gather soot deposits. Sandpaper is good for this job.
The entire area around the electrodes and burner should be blown out with compressed air.  This area gathers a lot of debris over a year of use.

Remove the gas line
Common sense: turn off the gas before removing the gas line!

Important note

Here is the gasket referred to in the previous picture

Burner and orifice: clean these with compressed air
Make sure that the tiny hole in the orifice is completely clean; use a pin or thin wire if required.

Install the new (or cleaned) ignition-sensing electrode