Hi, I have a 430 and after flushing its dribbling into the bowl, its a separate plastic tank with a 12v pump in it and a small button to activate it near the right hand side.
The flush works fine but its constantly dribbling, as if its being syphoned. disconecting the power doesnt stop it, only lifting the pump out of the water will.
Any ideas?

What's the model number of the toilet?

C250 thetford

The pump tubing inside the flush tank connects to a non-return valve which is fixed above water level.

A common problem is that the valve can come adrift from the clips holding it in place and it ends up lower than the water which then syphons through into the toilet bowl.

Remove the flush tank's top control panel to gain access to the valve and fix it back into place (if the valve clip is broken you could improvise using cable ties etc).

Make sure the pipework is secure to the valve and pump as loose connections can also cause problems.

Cheers for the reply. I only have a plastic tank hidden behind a wood panel, there’s a 12v pump in there that is activated via a switch panel.
I’ve took the cassette out and looks like the pipe just goes directly to the outlet in the toilet from the pump? It seems to be a syphon issue?

In that case I suspect the electric solenoid valve is the problem and is stuck in the open position causing the continual flow.

This valve is located behind the toilet bowl which will need to be removed to gain access.

Instructions for replacing the valve here.

Cheers John. I’ll have a look.