Dometic CTW 4050 toilet pump replacement

yorkyladandlass replied on 26/09/2018 16:20

Posted on 26/09/2018 16:20

Hi folks, the flush pump on my 6 year old toilet recently stopped working, just get a slight click when pressing flush button. Don't  think its fuse as it looks fine and various lights on top of toilet are working ok. Did a lot of web research and got a parts diagram etc and established you have to remove whole toilet to access pump. Undid six screws in floor of toilet access hatch and tried to lift it up off what I thought would be the interior wall plate fixing but cannot lift it up and did not want to force it. Think you may have to remove the flushing water filling fitting plate on the outside of the  van as there may be a short rigid pipe going into the flush water holding tank. Any comments apart from "its not worth the hassle just pay to have it done" which is what I am now thinking I will have to do. PS was concerned about the flush tank freezing before I could get it fixed so splashed out £8 on an AM-TECH deluxe syphon  pump to drain flush tank and worked a treat if anyone is looking at syphons. Hope this all makes sense to someone out there Lol

Hugo replied on 06/04/2021 23:48

Posted on 06/04/2021 23:48

Hi Yorkyladandlass

How did you fix problem in the end as mine is doing exactly the same and I just need to know how to access pump to check it out as it might just need the blades turning after lock down - Thanks

JohnM20 replied on 07/04/2021 08:53

Posted on 07/04/2021 08:53

Having had to take my Dometic loo out to replace the anti-syphon valve I can confirm that the water inlet plate has to be removed first. This is just four screws but you will need to VERY CAREFULLY cut through the sealant behind the inlet. I did this with snap-off blade craft knife with the blade extended to its longest. I put masking tape around the fitting so that the blade didn't scratch the surrounding paintwork. Once the inlet is removed the loo will lift out easily once the base screws are removed. Beware of  the 12v wiring which needs to be disconnected at the loo and there is also (on mine at least) a small drain pipe going through the floor. 

Replacement is just the reverse of removal but you will need to replace the sealant around the edge of the filler inlet plate. Clean off the old sealant first.

Hope this helps.

Hugo replied on 08/04/2021 22:06

Posted on 08/04/2021 22:06

Thanks John, looks like this weekends job I will let you know how i get on, much appreciated :-)

Richard12 replied on 09/04/2021 17:35

Posted on 09/04/2021 17:35

Our Dometic loo pump stopped working and I managed to remove the it once the screws were removed. It was very fiddly, but having removed the toilet I found there was nothing wrong with the pump, it was the flush button that wasn't making contact, sprayed it with cleaner and all appears to be working. 

I learnt quite a bit from dismantling the toilet. First, the pump could be replaced by a much cheaper version than the extortionate price dometic require, second, if the flush push button packs up I will not be paying £124.00 for a replacement PCB and wiring, I will find the two contacts on the PCB and wire it to a door bell from Screwfix which will cost me £3.45 to work the flush.

KeithL replied on 10/04/2021 18:51

Posted on 10/04/2021 08:29 by cyberyacht

One wonders why a PCB is even required merely to operate a push button contact.

Posted on 10/04/2021 18:51

 Because it lets dometic charge extortionate prices for spare parts to those who arent as tech savvy as others