Odours in vehicle interiors while stationary or driving may be caused by a number of different factors. Opening a window or skylight while your vehicle is in motion creates a vacuum in the vehicle interior, which then suddenly draws in odours from leakages in your cassette or in empty waste siphons from your septic tank.

Faecal odours:

• A broken SOG^® exhaust hose
  
• A leaking Thetford or Dometic gate valve seal 
  
• Insufficient sealing on the outlet lid 
  
• Leakage from all moving parts of the cassette
• In C2, C3 and C4 cassettes in particular, it is essential that the relief pressure valve on the cassette is closed because the gases could otherwise escape from the valve into the service compartment, especially while the vehicle is in motion.
  How to close the relief pressure valve
  
• In C250 and C260 cassettes in particular, gases can escape from the relief pressure valve into the service compartment when the insert that opens the valve in the cassette is not removed during installation. This release of gases is particularly severe while the vehicle is in motion.
  How to remove the insert
  
• In the case of a C400 cassette: is the cleaning chamber at the top of the cassette blocked?
• If you have a C400 cassette in which the SOG^® system is attached to the top of the cassette (using a special assembly kit), the valve inside the cassette must be closed.
• If you are using a replacement cassette, please check that your cassette has been coordinated with your SOG ^® system.

Sewage odour:

• Empty siphons (this may occur after emptying the tank) -> Run water through the siphons on a regular basis. 
  
• "    A dried-up siphon -> This is caused by irregular use of the shower in your vehicle, which may cause the contents of the septic tank to evaporate into the vehicle interior -> Run water through the siphons on a regular basis and close them.
  
• Siphons were not installed when your vehicle was manufactured. 
  

• A defect ventilator
• Leaks in the hose, adapter or connectors.
  
• If you hear a gurgling sound when using your toilet, this signifies an accumulation of condensation water in the suction duct. -> The suction duct must always be angled down towards the cassette or filter.
• In C400 cassettes, a bent rear insert means that the relief pressure valve in the cassette is unable to open. This leads to excess pressure in the cassette that causes the gate valve to become difficult or impossible to open. Another problem is that the seal between the insert and the cassette leaks, thus resulting in the constant release of unpleasant odours and limiting the suction power of your SOG^® system. The system's suction power is not, however, reduced by the length of the suction duct, which could be made much longer without affecting the suction power. It is essential that you use the troubleshooting set supplied with our assembly kits to solve this problem (see photographs)! Another problem is caused when the relief pressure valve gets blocked, thus causing it to stop working, even in the case of customers who use chemicals on a regular basis. The manufacturer therefore recommends that you clean your valve once a year.

• A defect microswitch
  You need to replace your microswitch.
• Using a second cassette from Dometic
  Please check that the control magnet is in the gate valve opening handle.
  
  
• The cassette is not closed properly
  This may be due to a deformed gate valve seal or a stiff cassette locking mechanism. (Replace the seal and treat with silicon spray once every couple of months. Thoroughly clean the cassette.)
• The Thetford C200 toilet, for example, has two catches on the gate value, meaning that the gate valve is not pushed any further once it has been closed using the first catch.
  

This gurgling is caused by an accumulation of condensed water in the suction duct during use and reduces your system's suction power. The suction duct must always be angled down towards the cassette or filter. When installing the duct, you must ensure that no siphon is created.