Dometic CTW 4050 toilet pump replacement
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
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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.
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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.
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One wonders why a PCB is even required merely to operate a push button contact.
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For the benefit of new readers who have a failed pump I hope the following will maybe save some unnecessary work. This is based on a Dometic CTW4050 toilet in a 2015 Lunar caravan but will apply to similar Dometic units.
If the toilet pump stops working, it may not be the pump itself that has failed. You can check a couple of things before ripping out the toilet (which you really don’t want to do unless you have to)
There are usually 2 fuses; the main one in the caravan fuse panel (10A on my caravan) and a second one underneath the toilet control panel (7.5A). Needless to say the 7.5A one should blow first and of course it’s the least accessible.
To get to this fuse you have to remove the control panel (orientations are given looking at the toilet with the word Dometic on the control panel being at the top). The control panel is held in place by 2 spring clips (similar to those found on a ceiling spotlight) at top and bottom. To remove the control panel use a couple of small screwdrivers to gently lever up the right hand side of the control panel where it sits in the casing. Once you have prised it up you can remove the control panel, and see the pump contacts and fuse under the panel. Check these are OK, and no obvious damage to the PCB or wiring/connectors. If all is OK, you will probably need to remove the toilet to change the pump – see previous posts - but just make sure you are getting 24V to the panel with a voltmeter.
If the fuse has blown the cause might be sediment in the bottom of the flush tank, especially if you use a pink flush additive. Dometic have not fitted a drain tap to the flush tank (!) so it is impossible to drain it completely either for winterisation or for cleaning. Dometic advised that best way to flush it is to pour warm water in to the flush tank and then pump it through at least 5 times. I didn’t want to stress the built-in pump any more by flushing the sediment though it so I bought a drill-driven pump from Halfords (https://www.halfords.com/tools/power-tools-and-accessories/power-tool-accessories/laser-drill-pump-221959.html) and sucked the tank up through the filling line with a bit of garden hose, which worked a treat. Something I will add to my winterisation routine.
I will have a look at the caravan wiring diagram and if the toilet circuit does not feed anything else I may swap the fuses round so that the 7.5A fuse is in the main fuse panel.
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My pump has stopped working on the Dometic CTW 4050 toilet. We have a Lunar Clubman 2014 caravan.
Thanks to, JohnM20, for a very good, step bystep guide, on how to remove and fix the problem.
I will have a go at fixing it sometime but for now, I think I may just use a sturdy two litre empty bottle, that I can refill and just stand next to the toilet.
I would just add. If you take the cassette out of it's housing and the top, left hand red light comes on. Well, is this not a sign that the pcb is operating normally and you do not need to remove the wall,(as it is called in the instructions book), to check the 7.5 fuse is working. Is this correct ?
Finally, a question to member, Marybeth, who posted a very good bit of a advice on how to help clear the gunge that builds up in the flushing tank. You mentioned, "make sure you are getting 24v feed to the panel". I am a bit ignorant here. I thought the caravan worked on a 12v system. What am I missing ?
Thank's for the advice. Will post when I find time to fix the problem, with the pump.
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The pump not working on our Dometic 4050 was just the final straw in a long list of things that went wrong with it within 5 months of getting the van - which is why we now have a Thetford. Touch wood - it's been trouble free for the last eighteen months. Best decision I have made in a long time - an absolutely useless piece of kit.
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Another tale of woe. Whilst away in Cornwall last week our Dometic loo developed a leak whenever it was flushed. Thankfully it was clean water. We temporarily overcame the problem by using a watering can in the caravan to flush the bowl.
Yesterday I took out the toilet (I'm getting to be a dab hand at this) and located the leak. Under the rim of the bowl there is a plastic elbow where the supply pipe joins the flush ring around the rim. This can only be seen with the aid of a mirror. Somehow the elbow had fractured. Don't ask me how as there is no stress on the elbow and no water pressure. This meant a complete dismantling of the toilet to get the flush ring free, the main problem is that the plastic supply pipe, 9mm bore x 15mm od, although probably flexible when originally assembled, has now become quite inflexible. Why such a thick walled pipe has been used is a mystery as there is no pressure in the pipe.
I've now got to get replacement pipe and elbow although this won't be coming from Dometic even though I can only locate, at present, pipe with a 12mm od. I'm sure this will be more than adequate for the job. I'll let you know when it is all finished and up and running again satisfactorily.
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I have a feeling I've seen a video on You Tube about how to fix this - which goes to show how common a problem it must be. I will refrain from any further comments about this particular piece of kit!
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We had numerous problems with a Dometic CTW 4050 too. In the end I replaced it with a Thetford unit. Its not a difficult job and our loo is now trouble free
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Well, that's it, job done. I found a supplier, ( PVC Tube Online Ltd), of the identical size water hose which, if anyone wants to know is actually10mm bore x 16mm od. They also sell the necessary elbows. The whole job cost me less than a fiver to do. I can't really count my time which, in total was about four hours including taking the loo out in the first place. Far cheaper than getting Dometic to do the job of that I'm certain but I shouldn't have needed to do it.
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I would ask, of those who know! When I have removed the Dometic 4050 toilet, as well described by kind members. What will I see when I look to remove and change the pump.
Is it easy to get to the pump, once I have removed the whole toilet and taken it out of the caravan, to work on?
I changed a pump, many years ago, on a Thetford and it was as easy as changing a light bulb.
Thankyou, for any helpful replies. Forewarned, as they say.
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I can only help so far, greeninit. I have not (yet) had to change the pump but have had to change the anti siphon valve. Once the toilet is away from the wall, disconnect the power supply at the plug connector and pull the narrow plastic drain tube up through the floor. On the back of the control panel but under the main housing of the toilet there is a plastic tab which is part of the control panel. Push this in and the control panel will lift slightly. On the opposite side to the tab is a spring holding the panel in place. This will move as the panel is gently removed but it will only move so far because of the wiring. There are two thin white wires which go from the tank to the control panel. These should be removed from the panel. There is no positive or negative for these so it doesn't matter which way around they are when they are replaced. There are a pair of wires that go to the pump passing through the top of the anti-siphon valve to the control panel. Disconnect these (it leaves short tails on the panel). There are four screws that hold the header tank in place. Remove these, supporting the tank. There is also the water pipe connected to the top of the anti siphon valve. It may be better to not disconnect this as getting it back on can be a bit awkward especially if the pipe is old and getting less flexible. From memory I believe the anti-siphon valve just turns to release it.
This is where my knowledge ends I'm afraid. I'm not sure how the pump is held in place, I think it just hangs in the tank on a short piece of pipe but I'm sure it will be quite obvious.
Hope this helps.
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just replaced the flush pump without taking out the toilet, remove the control panel with a couple of thin bladed screwdrivers, the springs are at 12 and 6 o clock, then the pipe to the toilet bowl, tricky but can be done, then twist the pump housing anti clockwise and manoeuvre out the housing and the pump,, the genuine Dometic pump was £55 bit I got a generic one off ebay for £9, fitted straight in, just had to put a couple of spade connectors on the wires and cut off the earth one, when refitting I replaced the fiddly spring clip on the pipe to the bowl with a jubilee clip.
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Just back from two weeks away and, yes, you've guessed it, more trouble with the Dometic toilet. This time it is the sealing ring between cassette and bowl that has started to leak. Not a difficult job to replace, just a costly one. For the seal it is over £35 for a rubber ring. Whilst searching for it online, I saw the Thetford seal that does the same job on Thetford toilets, it is only £13 !! Also during the search I found the Dometic elbow that is in the flush water pipe system. For this part Dometic want £18 !!!! I had already bought a pack of three completely adequate elbows for £4.29 from a PVC tube supplier. There is no physical stress nor is there any internal pressure on the elbow so why the original should suddenly fail is beyond me. I think we are being taken for mugs by Dometic. If I get any further problems with the toilet it is being ripped out and a Thetford installed. An expensive change, yes, but it's not always about the money especially when leaks are involved, and not just clean flush water
Interestingly it appears that Lunar, before they went bust, might have reverted to Thetford toilets. It wouldn't surprise me especially if they had received numerous complaints about Dometic equipment.
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Yet another tale of woe with a Dometic toilet. We've got our van booked in for the end of September to get the toilet swapped to a Thetford. I don't know the model they will use, but in a previous thread richardandros posted a few photos of their Thetford replacement, LINK
It's on one of the later pages; the thread makes for interesting reading I think. We've been away last month, and all went well with ours, although the "full" light stayed on a few times after emptying it, but we can't have it all I suppose
Our problem (up to now anyway!) has been different in that we were unable to actually get the cassette out in the first place, but if you read through the linked thread, you'll be able to read all that, won't go into it again here.Good luck!
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Same problem, rinse leak into the compartment. I removed toilet unit (CTW 4050), easy to check pipe fitting exiting from pump - no leaking, looks in perfect condition, but can only inspect bowl connection from inside with mirror and cant be sure of a defect or break etc. Getting to that part looks like a complete disassembly of the unit. Is that so? Any simple ways to do this. Don't really want to replace whole unit (expensive) and can't find a Dometic Agent who can fully service. In any case can not find CTW4050 in market place , only CTW 4110 - hopefully has same hatch and filler location holes.
Lateron , it was posted that could be replaced with Thetford,say 260 series which look the same but would hatch and filler holes in side of van be in exactly the same place?
Up t now using the several other forums, where no complete solution offered.
regards
Brian, Basildon Essex
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Would you please advise exactly what model Thetford was the replacement. Also was the filler hole in the side of the van in exactly the same place as the previous Dometic 4050, or was there no external filler - I think there are some models of the 4050 that don't have an external filler flush water - the external one that does is the CTW 4050
Photos won't upload - probably too big.
Brian
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Brian - I think it is the Thetford C263 -CS. The only 'problem' that you will have is that - as you rightly suspected - the filler holes don't line up - so it's not possible to use a Thetford model that requires an external filler for the flush tank. The 263CS has a dummy header tank so, to all intents and purposes, it looks almost identical to the Dometic from inside the van. The only difference being that the curve around the base is slightly different, so if you have a fitted carpet around it, it doesn't quite follow the contour of the new toilet. That said, unless it was pointed out to you, you would never notice.
The flush water, therefore has to come from another source - and in our case, in comes from the inboard tank - which supplies all our water for the van, anyway. (Filled up automatically from the aquaroll). I believe, however, that there is no reason why that flush water can't come directly from the aquaroll - just a question of putting the pipework in.
I was a bit sceptical, at first, about the water coming from the inboard tank and therefore not being able to put additive in - as I always had. In the event, I actually prefer it - no additive isn't a problem - we use a spray bottle if required - and not having to think about filling the flush tank is one thing less to do!
All of this renders the existing filler cap on the outside of the van, redundant. However, that again isn't a problem because the appearance of the van isn't altered and no one but you knows it's now just there for 'decoration'!!
This little exercise cost me £650 for the dealer to carry it out - and they have done loads because of all the complaints they had received about Dometic toilets - so they were well experienced at it. Although the van was only five months old, it couldn't be done under warranty because it wasn't a 'like for like' replacement. That said, it was the best decision I made because that blasted Dometic toilet was spoiling what was an otherwise, near perfect, van.
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Hi Brian
More of the flush water pipework can be fairly easily exposed for checking. Remove the seat with the tool which should have been provided with the Dometic handbook. This is pushed under the seat rim at the several points indicated with arrows moulded into the seat assembly. Once this is removed it exposes the flush ring. This can then be taken out by removing the screws, I think there are 8 of them. The ring can then be gently lifted and the pipe, the connection onto the flush ring and another elbow where the pipe comes through from the main body of the toilet can be examined. It was this elbow that had fractured on mine. There is plenty of slack in the pipe which is housed between the ceramic bowl and the outer plastic part of the bowl. Refitting is just a reverse of the foregoing.
If it is the elbow that has fractured may I suggest using the company that I obtained both the correct pipework and elbow from - PVC Tube Online Ltd. The pipe is 16mm with a 10mm bore and the elbows 10mm. I bought more that I needed including three elbows for just over £10 including delivery.
Hope this helps.
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Brian
I forgot to add that the above can be done with the toilet in-situ. If you need to replace the pipe or elbow I'm afraid it is probably a complete toilet removal as the pipework goes behind the header tank. See my earlier post about how I did it.
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Thats very helpful. I haven't got the 'tool' you mentioned so I will search for it in my record files etc or otherwise apply my 'prying' skills.
Next weeks job!
Brian
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Thanks Richard , very helpful if I eventually change to the Thetford. Was the cassette outer door in the same place, - used the original? I dont mind the water filler door being surplus.
Did you 'tee' off the cold water pipe which runs adjacent to the toilet (in my case heading for the bathroom). Presumably a length of plastic pipework and tap to squirt down the bowl when required or piped into and connected to the Thetford intake - did it need an anti siphon valve or was that within the Thetford?
As you say its worth the money getting it sorted but down here caravan servicing people are completely full for months so a DIY approach is more likely for me.
Thanks
Brian
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Brian
I did post some pictures on here of the installation (or it might have been Caravan Talk!). Either way, I can't find them and I seem to have Deleted User them from my phone/computer. I will take some more so that you can see the result.
The existing door is used but I think the Thetford cassette housing must be slightly larger than the Dometic because I have an additional surround around the aperture. It looks very professional, though, and anyone looking at it would think it was the standard fit. It's difficult for me to ascertain how it is plumbed in because most of the pipework is in existing trunking - but there must be a "T" somewhere from the existing cold water feed to the bathroom and it just connects to the Thetford toilet - press the button on the top and it flushes!
Another advantage is that since the header tank is a dummy - there is no condensation / dampness to get to the switch / PCB which I know seems to cause quite a few problems for others.
I have pointed a few others in the direction of ALV at Tebay who are used to doing the work and I know that at least one person is getting it done there - but is having to wait until September.
Good luck!
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