I have a Worcester 280 combi. I’ve just changed the water pump as the old one seemed to have a reduced flow, and was regularly sticking. The pump removed was set on setting 3, (100W, 1800rpm). So I’ve set the pump I’ve put in, also to setting 3, which in this case is 105W, rpm unknown. Now, when I start up the central heating from cold, the burner comes on and stays on for quite a while as you’d expect, and the all the radiators get nice and hot. After that, when the burner goes into its ‘maintain’ state of on/off, the radiators drop to luke warm, (regardless of the heat setting on the boiler), and the burner seems to be ‘short cycling’, ie. it comes on for only 2 minutes, off for 2 minutes, and repeat. I’ve bled all of the radiators. Anyone got any ideas what the problem might be? Thanks.