Hi Just noticed this since Friday, but after using the hot water tap in the kitchen, which is only a couple of meters from the combi boiler, the water is cold and takes a while to warm up. The burner fires up after 10-15 seconds for the water to start getting hot. Immediately after turning off the tap and turning it back on, the burner is off and then re-fires for the water to get hot again. The temperature on the combi goes down and then starts to climb again when the burner comes on. Could someone tell me what the problem is? Thanks in advance.