toilet flush

Harrytherid

Harrytherid

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To all you helpful guys out there





I have a Mc Louis Tandy 670g of 2007 vintage, the toilet flush in which has quit working. The fuse adjacent to the cassette is fine and I don’t know if there is another but there is a click when the flush button is pressed so it all would seem to be healthy.



I took the toilet out and on to the bench to facilitate removal of the solenoid valve



I removed the solenoid valve and connected it to a 12v and to a water supply on the bench. When the 12v is sent to the valve, water comes out of the valve as hoped. However, when the whole is reassembled and the water and 12v reconnected to the toilet in the vehicle and the button pressed, a click and no water, why? The tap at the nearby basin on the same supply pipe discharges copious amounts of air free water when required to do so.



Disconnection of the supply pipe results in a fountain from that pipe and the toilet piping demonstrating plenty of pressure



I am liable to go mad soon as this all makes no sense to me. Hopefully, someone knows something I don’t and will be kind enough to tell me and save my sanity
 
Do you know the make / model on your toilet,

There are many and they are not all identical

If you don't know make / model then first question is does your toilet use water from the main tank or does it have a separate flush tank.

The two different system have two different sets of problems.

If you don't know then look on the outside of the van js there a filler about the size of a packet of cigarette that looks like this?
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1782926816862.png
 
I had to replace the switch on my electric flush toilet on one of my vans. It seemed OK visually but had stopped working.
 
Thanks for the reply r4dent and how remiss of me not to put that in the question. It is A C200 S/CS which uses the main tank water which the pump gets up to quite a formidable pressure as I find to my cost when I disconnect it., good that it is warm weather. Note to self, switch off pump and run water until pressure drops and it it stops running before disconnecting.
 
We know that the pump is working so the problem is that the solenoid isn’t being activated.

We know that the solenoid works so the problem is in the DC supply to or from the solenoid.

Time to get the multi meter out…

Three quick checks before we start the tedious task of checking the wiring.

Job one is to test the Flush switch.

Job two is to check the fuse that protects the solenoid circuit. This may or may not be the same as the one that protects the pump.
If in doubt check them all one at a time.

Job three is to check the leisure battery voltage, solenoids can require a decent voltage.



If you have got this far then the chances are then you probably have a wiring fault.

Verify this by checking the voltage across the solenoid (with the switch on)


First check the resistance between solenoid -ve and ground,

Next test the voltage working backwards from solenoid +ve to identify the problem.



Good luck.
 
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r4dent said:
We know that the pump is working so the problem is that the solenoid isn’t being activated.

We know that the solenoid works so the problem is in the DC supply to or from the solenoid.

Time to get the multi meter out…

Three quick checks before we start the tedious task of checking the wiring.

Job one is to test the Flush switch.

Job two is to check the fuse that protects the solenoid circuit. This may or may not be the same as the one that protects the pump.
If in doubt check them all one at a time.

Job three is to check the leisure battery voltage, solenoids can require a decent voltage.



If you have got this far then the chances are then you probably have a wiring fault.

Verify this by checking the voltage across the solenoid (with the switch on)


First check the resistance between solenoid -ve and ground,

Next test the voltage working backwards from solenoid +ve to identify the problem.



Good luck.
Click to expand...
I saw a YT video about 2-3 years ago, where the pcb in the electric flush had failed. IIRC, the solution was to solder a short piece of new wire to restore the broken connection, rather than stupid money for a new pcb. Could a similar breakage on the pcb be causing the OP's problem?

Steve
 
With the unit back in the van and everything connected up properly, measure the voltage across the solenoid coil when you press the flush button.
 
marchie said:
I saw a YT video about 2-3 years ago, where the pcb in the electric flush had failed. IIRC, the solution was to solder a short piece of new wire to restore the broken connection, rather than stupid money for a new pcb. Could a similar breakage on the pcb be causing the OP's problem?

Steve
Click to expand...
Hopefully the tedious circuit testing will identify this,

If I was a betting man I would put money on the switch then a fuse then a bad earth,

Was the YT video that you saw for a toilet with a separate water tank? I suspect it was.
MERL said:
With the unit back in the van and everything connected up properly, measure the voltage across the solenoid coil when you press the flush button.
Click to expand...
Wish I'd said that... Oh wait I did say that (after checking the fuse; the switch and the battery.
 
r4dent said:
Hopefully the tedious circuit testing will identify this,

If I was a betting man I would put money on the switch then a fuse then a bad earth,

Was the YT video that you saw for a toilet with a separate water tank? I suspect it was.

Wish I'd said that... Oh wait I did say that (after checking the fuse; the switch and the battery.
Click to expand...
IIRC the YT was with the toilet being fed from the freshwater tank - I *think* the Van was around 2017/18 reg and the Influencer had owned it for around 3 years from new

Steve
 
r4dent said:
Wish I'd said that... Oh wait I did say that (after checking the fuse; the switch and the battery.
Click to expand...
Yeh, I'd check the voltage first and then check the fuse, switch and battery AFTER that test showed there was no/low power at the solenoid. Hence my post.
An affirmative test for voltage at the solenoid removes the need to test a whole group of possible causes. It's simply a case of economic testing procedure.
 
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Not possible to get to solenoid when all back together again. I have too many commitments to make it quick and am too old anyway so It will be a day or so before I have anything to report. Should get rid of the wagon really but must have it all working before I do.
 
Might have found part of the problem. Not yet tested but could not get reading from voltage across the switch but found rust in the 4 way connector block and replaced it along with removal of rusted wire ends and replacement with solder. Still no joy so now I find that the swines have changed the colour of the wires out of sight inside some opaque sleeving. The job gets worse. Do you think it is deliberate to fox anyone's diy attempts? I shall possibly resort to completely rewiring the whole unit. Why does the switch have 4 terminals? with 5 wires going to it. Any ideas? more foxing of DIY eh?
 
The plug and socket configuration is for ease of assembly and installation but these exposed terminals make for an excellent point of failure as you've found.
I think that there's an additional output coming off of the switch that activated a remote pump for a non pressurised system which of course you don't have. You've probably got a light which comes on when the cassette is full too. The flush circuit is dead basic , a supply, a switch and the solenoid it's probably simpler to rewire it?
What colours do you have at the main connector? Maybe a photo if you can.
 
That connector block is an ordinary domestic connector block the metal of which I would expect to be brass in its entirety. However, they have terminated the individual wires with crimps which are not brass and which have rusted though that rust might be just the residue from the tooling that made or crimped them. I shall experiment with a jury rig of wiring before finalising with a normally open push button momentary switch if that is deemed appropriate. I struggle with sending photos but will see what I can manage.
Your interest is much appreciated. Oh; the full tank light has not worked almost from new. The rather brittle wires going to it snapped at point of entry to the light. I just look into the cassette via the discharge blade hole. Every bit as good except once when a stomach bug caused an over fill which one of my spare tanks (I carry three) sorted. The light would have been ignored too. Too ill to bother.
 
From your description the issue appears to be the connections, maybe the switch too. You obviously have a decent electrical knowledge and the push to make momentary switch is exactly what's required. AI suggests everything Including power, the switch and the solenoid are all wired back to that block and a multimeter should reveal what's what so Personally I'd remove the connection block completely and connect everything up with soldered connections and heat shrink sleeve.
 
Dear oh dear, what have I done. Did the wiring a s suggested but with a manual switch, ie a wire to touch battery terminal to liven up. The solenoid began to smoke immediately and I am pretty sure it is now dead. The original wires had a pair of spade connectors to connect to the solenoid with a resistor between them, black about 4mm dia with a grey end 1mm wide approx, resistance now about 415 ohms. Where do I go from here, eh?
 
If the component you're talking about is connected across the solenoid then it's almost certainly a flyback diode, I suspect the smoke was coming from this diode and not the solenoid because you reversed the polarity of the solenoid connections. 415 ohms is about right for the coil resistance.
The diode should only conduct in one direction, if it conducts in both directions then it's knackered BUT if you've wired the solenoid up so that it's activated by a simple switch then the diode isn't required anyway and it can be removed.
 
As I read through this thread, I wondered "has he accidentally reversed the polarity?" Too late!
The good news is that you can easily get a replacement diode fo a few pence, but you can do without one anyway.

Not only will the diode be unhappy going backwards, but the solenoid valve won't open when a DC current pushes it in the closed direction.

Do fully test it before reassembling this time. They're a bit of a struggle to take apart and a lot of a struggle to put back together.
 
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