H3 code showing on my boiler?

I recently replaced my Ideal Icos HE18 boiler's PCB box because the readout on the User Control went blank, boiler completely unresponsive. (The User Control is at the lower right hand that has the boiler's on-off switch and water temperature knob).

Changing the PCB got the User Control to display, but with fault code H-3 alternating. When I took the PCB box out again to doublecheck that the jumper settings were correct according to the sheet that came with the kit, I found they were OK, but just by chance I noticed that there was a jumper on the new User Control's own PCB, but none on my old one. I removed the jumper from the new User Control, put it all back together, and the boiler fired nicely!

So--it would be worth checking this on any new PCB box kit that you buy!

Incidentally, I ordered the PCB kit midday from www.idealboilerparts.co.uk and it arrived the next afternoon using the cheapest delivery. How about that for service?

Don Ferris
August 2015

Anything is no easy on this boiler

Sandjheating
October 2014

dhw (domestic hot water) thermistor fault. will need to be replaced. its nothing major a small part fairly cheap and easy to fit.

kash
March 2013