Vetus Toilet 12V not sucking waste into tank- just holding it in the bowl

[LondonBoatOwner]

Hi guys,

Thank you in advance to whoever can solve this. I have had a Vetus toilet- no big issues for three years.

However, there was a bad smell coming from the 38mm sanitary hoses and 25mm direct from toilet hose. I replaced these with Eurocord Sanitary W.C after being recommended these were high quality and less likely to smell. However after swapping all the hoses we tried to use the toilet and the water simply will not suck away any more. The push and hold button the the vetus control panel whirs and it usually would work but no suction from the bowl.  

I went to the website where they had these faults listed:
 Possible cause • The air-relief valve does not shut properly. • The outlet pipe is blocked. • The pump housing is blocked. • The sieve is blocked. 

Solutions:

Solution • Clean the air-relief valve, or replace it. • Descale the outlet pipe. • Clean the pump housing. • Clean the sieve

I took the entire pump apart cleaned it, reinstalled it and still the same issue- I have a feeling the air relief valve has now coincidentally given up the ghost, however, https://www.vetus.com/en/spare-parts/waste-water-systems.html?p=3  you will notice there is no mystical "air-relief valve" on their spare parts section. 

Has anyone else come across these issues? 

Cheers,
G