For the machine to keep filling it would indicate that there is a siphoning problem. Check the outlet hose is not running along the ground, it has to rise up then loop back down or the water will just run straight down the drain. If the problem only happens after the first pump out it would indicate the end of the outlet hose is lower than the drum or there is no air break around the outlet hose. (The
stand pipe should be larger in diameter than the hose from the machine).
http://selfix-uk.co.uk/under%20sink%20plumbing.html
×