Johno, I need your help, how do I size a low loss header, there is no information on it anywhere. My customer has a gigantic house, 33 radiators, he put a massive pump on it to drive it to all rooms because his boiler on its own was too wussy to over come the resistance, well ok, but the consequence is that there is not enough delta t across the flow and return so the boiler modulates at a lower than optimal temperature. I phoned Vaillant, they suggested a low loss header to create a neutral point and provide hydrolic separation, ok thats fine, but how to size the thing? No one knows, all engineers I know are dunces, no one on the internet can help, you are our only hope, your fan Roo.
boiler is Vaillant light commercial, 44 Kw , S-pan, unvented cylinder and rads, lots of rads. Design temp delta t is 20 Celsius. It has an internal pump and an external more powerful pump that the householder installed in an attempt to overcome the resistance to the heating circuit. Vaillant propose hydrolic seperation i.e a low loss header. Thanks so much for taking the time Johno.
