in good shape - brunnhilde part 2

Brunnhilde has been sitting idle for the winter months. I recently took her out for a bit of exercise, to make sure everything is shipshape. About 2 years ago after sitting around for months, she developed the limp home mode which turned out to be the oxygen sensor became defective.



Well sure enough something mechanical bounds to go wrong. The Thetford cassette toilet failed to flush. I immediately check the 3A fuse in the toilet, and it is blown. While I was quite certain the 12V water pump must have seized from months of disuse. I put in another fuse. My smallest one is 5A. While I thought it is not a good idea I decided to use it, thinking the weakest link (such as the traces on the PCB) in the toilet should be able to tolerate 5A of current. This time the fuse did not blow but still no sound of the pump.

Even before pulling out the pump I suspected Thetford used a cheap pump in the toilet. The water pump in my VW Vanagon Westfalia still in perfect working order after 26 years of continue submerse in water.

Time to pull out the pump and check. I know I will need a 12V power supply and a heat gun to help soften the stiff PVC hose that is very stiff in the frigid temperature.

The pump is located inside the flush water storage compartment. The water compartment in this toilet is built into the front of the toilet that is extremely narrow. There is barely enough width for the pump and with the PVC hose being so stiff I was afraid I would break the plastic nipple it connects to he flushing jet. Also even with my relatively thin hand I could barely make a grip because of the tight confine.

With a lot of patience I was eventually able to coax the pump out of the cavity. Yes, I was so right. Thetford indeed use a cheap pump - with their own branding. It look remarkably like a cheap no-name pump that I keep around as an emergency spare.

removing the control panel to gain access to the pump

 everything is consumer quality so it pays to be very gentle, especially in cold weather

the cheap Thetford pump - it must cost them no more than $2; RV toilet is a very lucrative business especially the sell-up models like this one

I went and fetch my spare cheap pump and place it side by side with the Thetford. It is identical in every respect, down to the color of the wires. The only different is the branding.

 identical down to the color of the wires - brown is positive (note to self)

I used the tip of my DMM test probe to spin the impeller and I could feel the shaft has seized. With a bit of force I was able to spin it free.

After spun free the pump I used the 12V power supply to test the pump and sure enough it worked. I gave it a good amount of run time to free up the resistance that caused the seizure. I would prefer to replace it with a Comet VIP pump but I don't have one around. I placed the Thetford pump back and assembled the toilet. For the following days I have been giving the toilet an occasional flush and so far so good. I expect it will continue to work indefinitely.

 comet VIP

comet VIP-Plus would not be suitable because the flow rate would be too high for the application

the 26 years old German pump in Isolde (my Westfalia Vanagon Camper) - it looks very similar to the Comet VIP that you can turn the impeller with your fingers

I have been working on a plan to freshen up Brunnhilde's sun-bleached exterior plastic bumpers, wheel arches, and the chip guard paint surface on the skirt.

this are color choices of off the shelf spray bombs

I have been giving it a lot of thought between buying mixed paint and painting it the professional way versus buying custom-mixed spray bombs (also automotive paint).

I also have another project that requires spray painting of plastic. I am in the process of converting the propane refrigerator in Isolde to a true DC compressor one. I have been tasting the refrigerator for a very long time at home to be sure the project is a go. This refrigerator can achieve sub-zero temperature of a freezer. The original propane one can barely keep a piece of meat from spoil, and only if you put it right next to the evaporator fins.

12v dc compressor refrigerator that i have been testing at home

i hacked a computer power supply (old ATX) into a 12Vdc only power supply to power the refrigerator; all my other power supplies does not have enough current to sustain for initial surge when the compressor first turns on

One challenge is to match find a plastic laminate (formica) that comes close to color of the original grey of the interior cabinets for the door. I have been toying with the idea of using completely different color and with modern abstract graphics. I picked out some of these samples. They are all Formica brand.

For the frame of the refrigerator door will be painted the deeper grey as the Westfalia cabinet moldings. The door will have an insert made of one of these Formica laminate. One problem is I have to buy a full sheet that is 5 x 10 feet at a cost of about $120 plus shipping. I would want to use the rest for some home furnishing or architectural projects.

i like the green, blue, and orange ones and any will add some live to the very restrained Westfalia design