I've got a Sealand Model S vacuum venerator that stopped working. Not sure if it's the vacuum side or the macerator pump side. When the pedal at the toilet bowl is pressed - there is no suction sound, the indicator remains red with the ball closed and with the ball open the space below looks pretty full. I've read about a vacuum relief valve that might be leaking (keeping a vacuum from being generated) but can't seem to find it and I wouldn't expect all the fluid below the ball if that was the case. I'd appreciate any trouble shooting thoughts! Thanks!