The boiler isn't lighting. We definately have a gas supply as the gas cooker is working fine. There is an error code F4. Apart from that, I have no more info, sorry it's vague.

Madeleine, December 2008

it is a faulty sensor on the condensor trap.
Disconnect that wire, tape it up and it will run fine

Terry mechan, December 2016

no power to the timer, wires showing continuity and pcb fuse intact,

Frank boy, June 2016

i had the same prob on my heat line boiler.
i took the igniter out and slightly opened the gap on the spark and its been working fine .

john, January 2015

put it in the bin and buy a proper boiler

a gas engineer, October 2010

I would just like to thank Phil as i have just woken up o my boiler with the F4 Fault code and i have just managed to get heating and hot water back through using his advice. People this is your first port f call to sorting this problem... Thank Again Phil.

Geoffrey, February 2010

the f4 seems to come up on new boilers after the condensate trap gets condensate (water) on the contacts at the upper drain out point (where the sensor is located), if u pull off the blue plastic cover and let it dry out (a cloth gently inserted will help but not loo paper as u dont want bits of paper flaking off), once dry (may take upto an hour) try restarting the boiler (this may take quite afew restarts and power offs/ons etc but it usually works for me,
Make sure u replace that blue cap and dont dislodge any other wires or pipes with fat fingers!!

Boiler works for ages with no problem then has this ffault for no apparent reason GOOD LUCK VIZO OWNERS!!

PHIL, November 2009

heating but no hot water no light on facia for hot water when tap turned on

bob, September 2009

code F4 how repair

kris, January 2009

please please please remember these are gas appliances, unless you are competent, or have a form of understanding of these units, do not touch them,
i am aware as to how desperate the situation is but safety is paramount. if you have someone who knows about boiler repairs that is the route to take they must be corgi registered!!! the faults you are describing are pretty straight forward, ie codes etc
but for you to diy it, is not a good idea.

owen, December 2008

I now have this error today of all days!! However I have found this thread which may help

http://www.diynot.com/forums/viewtopic.php?t=153268

vincey, December 2008