I have been using this for quite a while now and forgot to post anything about it. I have just been reminded by a recent question on http://www.motorhomefun.co.uk/
If you are fulltiming you need to be aware that the toilet and boiler were designed for leisure use. This means their expected duty cycle was a couple of weeks away a year plus some weekends. They were never intended for permanent use.
The boiler will therefore get scaled up quicker as will the cassette toilet. I had my toilet totally jam up due to limescale after 4 years of use. This was not a pleasant job to fix.
I used to use white vinegar to clean my kettle but this meant filling the van with nasty fumes and could sometimes affect the taste of the water. It was suggested to me that I try some food grade Citric Acid. I bought a packet of this and set to on the boiler, the toilet and the kettle.
Cleaning the Kettle
I started with the kettle. I boiled up some water and made my self a coffee. I added a little cold water then a quarter of a cup of the citric acid granules. It fizzed mightily and after about 15 minutes I looked inside the kettle the medium to heavy scale had all gone. The kettle was as shiny as the day I bought it. Excellent result.
De-scaling the Truma Boiler
After the success with the kettle my next job was the boiler. This was trickier as I didn’t want to run it through the tank. I constructed a pipe with a funnel attachment. I disconnected the top pipe off the boiler. I then drained about a litre or two of water out of the boiler and poured a mix of half a cup of citric acid and hot water into the top pipe of the boiler using my contraption. I then switched the boiler on for about 25-30 minutes to get it nice and hot. I then let it cool down before draining it using the frost protection dump valve. The water that came out had a slight chalky colour to it so I am convinced it cleaned my boiler as good as the kettle.
Cleaning the Thetford Cassette
The final job was the yucky one. I removed the mechanism from the toilet cassette and rinsed it down using a small stiff brush. This left a surprisingly large amount of lime scale which was limiting the movement of the mechanism. I then soaked the mechanism in a tub with 1 cup of citric acid. I agitated the water every 5 minutes and big chunks of limescale started to fall off. After about 20 minutes or so I rinsed it down and made a fresh tub of the hot solution. After this soak the rest came away including around the seal. I then gave the whole mechanism a good coating of Silicone spray. When I put it back in the toilet it moved nice and smoothly and gave a satisfying click when closed.
I highly recommend keeping a packet of this stuff in your van. There are other sellers on Amazon and Ebay as well as these guys who I bought mine off. Bigger Jugs Food Grade Citric Acid…