TMC Electric Toilet - Struggling to pump out

[B40-Lefkas]

We have TMC electric toilets on our 2008 B40.  The forward head works PERFECTLY but the aft one struggles to get waste out of the bowl and we have to frequently close the seacock to get the water out.  Seems definitely like back pressure from the discharge as sometimes waste will be forced into the raw water side of the pump and recycled around the bowl.

We had all the piping replaced 2 years ago but the problem persisted. There is minimal calcium carbonate buildup that I can see.  I unmounted and swapped the two toilets, but the aft problem persisted so it’s not the units themselves or the flapper valves.

• Aft holding tank is about 20cm higher than the forward one. Could it be that the pump does not have enough head? TMC say 4ft max. If so should I add a second pump?
  
  How easy it is to remove the whole holding tank for cleaning?

Any ideas welcome.
Thank You!

[Rampage]

The symptoms point to a blocked outlet pipe or sea cock.  Given that you’ve swapped fore and aft heads and the problem persists, your next step is to strip out the pipe work and valves and check that over. 

[Impavidus]

Go to the local hardware store and get some Aqua Fuerte. (Spanish name)   Poor half a liter in the boal and the pump a few seconds.  Leave it 20 mins to foam up. Flush away with water. this stuff is great but you cannot buy it in the UK.

Ant & Cid

[stevem]

I have the same problem on my V42. In my case it is the length of the waste pipe from the toilet to the holding tank being too long over two metres. A design fault. I’m thinking a hand operated pump is simpler and more reliable.