We have a old main and a new mains water pipes, I would like to connect both to the boiler so we get good water flow upstairs and downstairs. I would like to know if you can connect two mains pipes to one combo boiler
Mo... no as your boiler is set to operate at a maximum operating water pressure. I would advise fitting a pressure reducing valve to your incoming main, then the pressure to boiler from water main can be set to the proper maximum water pressure. A good pressure reducing valve will come with an operating cauge
I hope this helps!
J Ireland Plumber