can anyone work this out. on a two port central heating system when hot water only is switched on the return pipes to the radiators heat up.both motorised valves have been replaced and are working fine.have bled all air out of system.any suggestions would be appreciated.
the waste from two hand wash basins join together after the bottle traps.when a basin is used gurgling noises come from the other basin and bad smells, the waste pipe is under a tiled floor. is there any kind of air admittance valve i can fit below the wash basins :?: