My Jaguar 28kw boiler shows F3, this is supposed to be a blocked heat exchanger, i have checked them all they are clear the boiler when starting goes right in to this fault code even with the pump switched off, any ideas?

alan stead, February 2008

When it did that to me, it had something to do with an oversensitive thermistor on the outgoing domestic hot water pipe. MInd you, I haven't got it solved yet.

Fabio, February 2008

yes mate, remove outer panel and inner panel, about 3 quarters up on left hand side you will see 2 wires, inbetween wires is a red plastic button, gently press with a screwdriver, if you hear a click its reset. ps dont forget to turn off power first. after click, switch back on power, j1 will come up, press reset and away you go. good luck

v matchett, February 2008

have you removed the heat exchanger then to see that its not blocked as there is no way of telling (other than fault code) to tell.the central heating side of the exchangers tend to scale up but the water pressure to taps remain normal,except no hot water, only cold.

ck, February 2008