I am shifting the washing machine from the kitchen to a utility room that funny enough has no drainage facilities.
Knowing most appliances have 1.50mm wastes, could a back flow be caused using the smaller 1.25.
Reason for asking are two obstacles. 1. a surface water drain pipe which will take the 1.25 behind it. 2.'Er who will be obeyed :cry: has asked if 1.25 can be used it will show less' I sighed heavily as I explained as both pipes are white either will be visual you silly moo, she slung I ducked and the saucepan hit the wall.
The other alternative is to start 1.50 internally and on reaching outside reduce to 1.25 pipe on the outside wall.