I hope someone on this site can help.
Could you tell me if the 373 holding tank has a non-return valve on the waste pipe to sea? I can not see anything obvious, but it maybe part of the elbow to pipe connection at the bottom of the tank.
The reason I ask is that the tank is blocked and so far I have not been able to clear it. I have tried pumping air back up the outlet pipe but with no joy. Hence the question regarding non-return valve.
Any suggestions are more than welcome.
Thanks
Kevin
