Preparing our 2013 Troll 540 for use, when checking that the toilet flush worked - pressed the button & nothing. :( Prior to putting the Eriba into winter storage, I had completely drained the flush tank, then put some fresh water in so as to be able to flush the pump clean of pink liquid, operated the pump then drained out the fresh water. So at that point all was OK.

The 540's instruction manual is not a lot of help, neither is the Thetford booklet nor their website. Anyway, I discovered a small removable panel in the waste tank compartment which holds a 3A blade fuse - which had blown. Fitted a new 3A fuse, pressed the button, still nothing. Checked the new fuse, it is still intact. So, what next? Presumably a new pump but how to access it? All help appreciated!

How to replace Thetford C402C flush pump

Many thanks for such a comprehensive DIY guide!

My problems is that we are less than a week away from heading to Spain and have much to prepare, so I might well have to grit my teeth and see if a local mobile service chap can have a look. Also, even with a new fuse fitted, there are no audible signs of anything happening in response to pressing the flush button - are there any other fuses elsewhere in the circuit?

Thanks again.

I know this might sound dubious but worth trying. Someone posted on here a while ago that their toilet wouldn’t flush after a prolonged period of non use. They presesed the flush button on and off for a couple of minutes and suddenly the flush started working. We’d started having the same problem in our previous Troll 555, tried this, and it worked. Don’t know whether the impeller sticks after a while but possibly worth a go before you spend any money.

Cheers Mark

Quote: KeithDM wrote in post #3

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Many thanks for such a comprehensive DIY guide!

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Thank you both for the suggestions. Tried the 'repeated push of the flush button', no joy. The great majority of our lights are LED and I was not able to perceive any dimming. As a last gasp / clutching at straw I turned all the power off again and removed the 5A and 7.5A blade fuses from the CSV409 to check them. Both were intact, so put them back, turned everything on again and in a fit of optimism, pressed the flush switch - Bingo - instant action! Phew :) Presumably one of them was not seated properly, although there was nothing visually obvious. Preparations for our departure for Spain can continue (hopefully) without further distractions!


Thanks again.