Hi, I have a Ferroli Modena 80E boiler, which has been regularly serviced and works fine. However, in the last couple of days, the boiler has started making an intermitent clicking noise. It only seems to happen when the CH has been running for a few hours and happens when the burner is on to heat up the water. The LED (which indicates the burner is on) does seem to flicker a little when the clicking noise happens. The sound is almost like a relay switching on and off. But if I push on the front panel which holds the LED the noise stops. Could this be a dry solder joint, or some other fault with the PCB ? The boiler was serviced just over a month ago - all internals, flue, fan etc cleaned, both CH and DHW thermistors changed (as water temperature was constantly hot and cold) and venturi upgraded along with APS pipes. Any help would be greatly appreciated.