The impeller on the flush pump of the Thetford C262 toilet in our 3 year old caravan has seized up twice recently, the first time after standing from November to March and then again after standing from April to July.
I have managed to sort it both times, but this has never happened previously (we've had caravans since 1993) and so I wondered if anyone has any ideas why the impeller gets seized up and what I can do to stop it happening in future.
Have the exact same problem in our old coachman laser.
Thought at first it was the fault of adding the pink stuff!
So replaced the whole impeller unit and stopped using pink went onto Zoflora type stuff. That only stopped the black bits.
The new motor / impeller still stick up after a few weeks of none use.
It's an easy enough fix, freeing off the impeller, with a small pick. However still a nuisance every time.
I even thought of changing to Hand pump type.
Maybe one day.!!!!
Please let us know if you find the correct solution.
the only thing i can think that would stop this for you all is to drain the water out of the pump before your last outing, which is what we do as we never travel with water in the caravan anywhere, never had the problems your describing
I don't usually drain my tank between trips, only for the winter layup, and for the first 4 years of my ownership the pump always behaved itself, but then last year (assuming original pump, that'd made it 6 years old by then!) after about 9 months of no use with a dry tank it wouldn't work! Pulled it out, tweaked the impeller and off it went, ran smoothly and quietly without any obvious sign of imminent total failure, been OK since.
As to why! I suspect there is a little bit of water ingress through the shaft seal, maybe even into the lower bearing, which when dried out causes a bit too much 'sticktion' for the motor to overcome and start. Probably also a bit of drying out of any 'oil' in the bearings which makes them 'sticky' too, which adds to the motor's load.
Cure! None that I can see, the pump is a sealed unit without any means of disassembly without breaking apart the casing (almost certainly rendering it beyond reassembly!) to gain access to seal to apply any lubricant.
Now a replacement Thetford pump has RRP of nearly £60, even at discount still around £45! I found a 'pattern part' Comet branded replacement on ebay for under £18, so bought one as a 'spare', so I can swap it should the need arise when the fitted pump can't be 'tweaked back to life'. That Comet pump is absolutely identical to the Thetford pump in every detail, and I suspect is indeed the source supplier that Thetford get their own branded pumps from. It's made in Germany, not some dodgy Chinese copy! Only minor inconvenience is that Comet pump has bare wire ended cable and Thetford one has a plug on it, but simple enough for me to refit the plug.
Replacing a faulty Thetford pump with the Comet pump is a well publicised 'fix', and I suspect a good many thousands are doing sterling service at a fraction of the cost of an expensive (but identical!) Thetford pump!
It’s a coincidence to see this problem! as our Thetford loo also stopped pumping yesterday (fuse ok). Getting the blades moving again looks easy on YouTube but getting the cover off the cistern & the 4 screws out looks a big tricky. Anyway, we’re not in a rush because it’s emergency use & strictly Ps only. We have a temporary “jug for water & dettol” system which works fine for now.
Many thanks for the replies - reassuring to know we're not on our own!
We too always empty all water out of the van before travelling, but the pump has still seized!
I think the way forward is the "spare Comet pump fix" as suggested by Monty15 - or maybe even permanent replacement if it happens again.
FionaW - we were quite concerned about attempting the fix as seen on YouTube, but were pleasantly surprised how straightforward it was, so go for it!
On the subject, I’m replacing my seized pump with a comet one. Trouble is, I can’t remember which way the big connecter fitted on the circuit board (I should have taken a photo, I know…)
Anyone know? I tried just now, and managed to blow a fuse, and don’t want to cause any more damage.
Thanks, James
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Topic: Why does the toilet flush pump seize up?
via mobile 27/7/2023 at 6:06pm
