I am getting different advice from plumbers on fitting a toilet in a bathroom that originally contained just a basin and bath. The stack is internal , it comes into the garage then bends into the bathroom. It cannot go straight up (so can externally vent) as it would go into the bedroom over the garage and there is a window right next to the wall so I cant even box it in.
The bathroom is not big enough to vent the pipe up as its only just long enough for the bath.
The floplast AAV (AV110 & AF110) specifications (see below) says it is A1 complient and can be fitted under the spill level but must be 20cm higher than the highest wet entry into the stack. Does this mean I can fit it under the bath as long as its 20cm higher than the lowest entry into the stack (toilet) even though the basin overflow will be higher?.
[b]Description : A1 approved in accordance with BS EN 12380, can be installed below the flood level of connected appliances. FloPlast are the first company in the world to be awarded the Kitemark for Air Admittance Valves in accordance with BS EN 12380:2002, licence number KM512474.