hi, i have an old style central heating system, boiler, pump, 3 way valve. For ages now i have been trying to solve the reason behind bad knocking of the pipes when the heating starts up. Recently i changed over the pump which had finally packed in, this did not resolve the banging.
What i did realise however was when i connected the pump direct to a wall socket and had it running before i started the heating system i no longer had the banging. I then worked out that when everything was reconnected properly again that the pump was not actually been asked to run by the controller for a few seconds (maybe longer) after the boiler had fired up, i think this delay causes the banging (maybe kettling effect).
My question is: Is it normal to have a delay between the boiler firing up and the pump being asked to run ? and if so what is the reason for this ?
What i did realise however was when i connected the pump direct to a wall socket and had it running before i started the heating system i no longer had the banging. I then worked out that when everything was reconnected properly again that the pump was not actually been asked to run by the controller for a few seconds (maybe longer) after the boiler had fired up, i think this delay causes the banging (maybe kettling effect).
My question is: Is it normal to have a delay between the boiler firing up and the pump being asked to run ? and if so what is the reason for this ?