I am fitting a boiler where the system has a 22mm open vent and 15mm cold feed. Does the cold feed have to be increased to 22mm even though I have 22mm open vent and pump over-run ?
take it this is a boiler replacement or you have insuficient water supply. because goin to a sealed system using a robokit extra would be better option all round
Thanks. In reply to your question, no particular reason other than keeping costs down as would not seal an old system without a pressure limiter....plus, boiler is being fitted for a 'song' !
the robokit comes with filling loop, pressure gauge and expansion vessel .look at the price, and its that much less costly than pump overrun if you have it