Thetford toilet installation - Wiring

tuggersbmx · Senior Member

Thetford toilet installation - Wiring

T1 Terry · Guru

Does the toilet have its own pump and a tank for the pump to draw the water from? If yes, the grey and purple wires should be protected with PB connectors because they are not used. If you are relying on the main house pump to supply the water to the toilet, then the grey and purple wires go to the relay that powers that pump so it starts up when the button is pushed. Make sure you use decent size conductor cable to the toilet if it has its own internal pump, voltage drop from under size cables is the major cause of toilet flushing problems.

T1 Terry

tuggersbmx · Senior Member

Hi Terry,

Thanks for your assistance.

The toilet does not have its own pump, I have a 12V pump to install soley for the toilet.

I also have a 12V pump soley for the my instant hot water system and a 24v pump spare.

So when I wire up the 12v power supply to the neg a pos (black and red tabs) on the toilet control does that also power the 12V pump? Or does power need to be supplied the the pump from the fuse box also?

If I just wire the grey and purple wires straight to the 12v which one is pos and which one is neg?

Cheers Mick

blaze · Guru

pump nneds to have power supplied from the battery via a relay. the wires are only triggers to operate te relay. I run mine off the motorhome water pump, the switch for it is locate at the sink that is next to shower and toilet, just switch on manually when water is needed at any of them
cheers
blaze

T1 Terry · Guru

tuggersbmx wrote:
Hi Terry,

Thanks for your assistance.

The toilet does not have its own pump, I have a 12V pump to install soley for the toilet.

I also have a 12V pump soley for the my instant hot water system and a 24v pump spare.

So when I wire up the 12v power supply to the neg a pos (black and red tabs) on the toilet control does that also power the 12V pump? Or does power need to be supplied the the pump from the fuse box also?

If I just wire the grey and purple wires straight to the 12v which one is pos and which one is neg?

Cheers Mick

Purple and grey go to terminal 85 and 86 on the relay, doesn't matter which way. Pump positive goes to terminal 87 and battery positive with a fuse goes to terminal 30. The pump negative goes to battery negative. The red and black at the toilet, red goes to a fuse and battery positive, black goes to battery negative. The idea is a button push at the toilet both opens the valve and powers the relay to close so the pump starts up and pushes water through to the toilet.

T1 Terry

Peter_n_Margaret · Guru

I found the electrics associated with our Thetford to be problematic and unreliable.
Why on earth do we need a microswitch to stop it being flushed when the cassette is removed? Does not stop the toilet being used, just stops it being flushed and it is obvious when the cassette is not there.
The supplied pump is problematic and frightfully expensive if an original is purchased for replacement.
I have replumbed mine to draw flush water from the normal van water system - no dedicated pump and no electrics now remain and reliability is much improved.
Cheers,
Peter

tuggersbmx · Senior Member

Hi everyone / anyone.

I wired up the relay but could not get it to work.

Do all 12v thetfords have a micro switch that disables the flush button when the cassete is out?

I gave up on the wiring and moved onto fisnihing off my roof but Ive realised I had the cassette out while testing the electrical /water supply.

Thanks.

T1 Terry · Guru

Yes, it won't stop someone sitting on the throne and making a deposit, but it will stop it being flushed as well making an even bigger mess.

T1 Terry