My oil fired combi Boiler (Eurocal) works fine when heating the rads, but over the last month or so I've noticed that the domestic hot water tends to run from hot to luke warm in about three minutes. The boiler is fireing away when the tap is turned on but with little effect. Any ideas? :?
It is possible that your water utility has repaired a lot of water leaks, and has uprated the mains pressure in your area. Try reducing the rising main valve feeding thro' the combi to your hot taps;- just strangle it a little. My own home town has been completely re-piped, due to foul deposits lining the pipes, + they installed header-tanks inside 2 tall hills to enhance the static pressure, should a pump fail.