Indirect hot water system pipe layout

[bbasmdc]

Hi, my builder has rerouted my DHW pipework and we cannot get the air out. Interestingly the cold water "top up" to the boiler joins the flow vent and connects to the flow side of the piping. So as the boiler is pumping the hot water it is fighting against the cold water top up that only has gravity on its side.
Isnt it normal for the cold water boiler "top-up" that comes from the header tank to connect to the return path to the boiler?
Regards

[justlead1]

Hi. Historically the cold feed to the system would have been connected to the return. However heating has been *******ized over the years so as to reduce cost etc. Once you introduce a circulater / pump the physics change, as a result you may find that a connection into the return will cause water to push out of the heating system vent pipe providing you with a radiator in the loft in the form of a cistern, not recommended. There was a time when the practice you describe appeared in text books. Now the majority of new systems are pressurised sealed systems which allow artistic liecence to the installer. Good Luck