ideal combi boiler - LF showing and cuts out on hot water

[mitchs02]

Please help - we have a three year old Ideal Combi boiler. Last year a new control panel was fitted as LF (does this mean low flame?) kept showing then system would shut down - particularly when turning on hot water but sometimes when turning on central heating as well. There would be a banging noise when you pressed reset to get it working again..
Problem was fixed but one year on exactly the same thing is happening again so we have no hot water and we're having to press reset lots of times to get from LF to heating on...
British Gas say it must be that pressure in gas pipes leading to the boiler are too low but this system has been in place for over three years and why - when the same thing happened a year ago - did replacing control panel in the boiler sort it out??
The pressure reading they took in boiler was 16 (this doesn't mean much to me so no idea what it's measured in) when heating on - but then it falls right back when you turn hot water on - so not enough gas to work the boiler apparently..
We are desperate as to take up the floor and start again with gas pipes would be a huge huge job and why has it worked for 3 years and why does gas supply to cooker work fine? Is there anything else it could be and has anyone got any suggestions - please...
much appreciated...

 

[corgiman]

16 is too low

did they suggest the gas meter govenor?

if not get a second opinion asap

 

[mitchs02]

16 is too low

did they suggest the gas meter govenor?

if not get a second opinion asap

Many thanks - what is a gas meter governor - they went outside to the meter and said it looked OK fromt he street...the gas cooker is showing full flame etc...?
it is really good to reply to this - we are very worried about it

 

[corgiman]

get a second opinion is my advice

 

[gas4you]

I would suggest getting the boiler serviced properly, not an annual safety inspection from BG with an FGA up the spout

First course of action would be removing the condensate trap and the sump cover and cleaning thoroughly.

I would go as far as to say 90% of L:F faults are this.

 

[heatingman]

As gas4you said, get the thing serviced, not safety inspected. Also call National Grid to check the governer, it sounds like it might be locking out when placed under high demand.

 

[mitchs02]

As gas4you said, get the thing serviced, not safety inspected. Also call National Grid to check the governer, it sounds like it might be locking out when placed under high demand.

many many thanks to both of you - I will do that and keep you posted. It's fantastic to get good advice and very much appreciated...

 

[gas4you]

Blocked condensate trap/sump will give erractic readings to the gas inlet pressure, enough to make one think it is a faulty meter govenor.

I've been caught out with this in the past, once, never again

 

[shambolic]

TBH 16 is ok for an Isar and Icos when taking dynamic pressures(although the amount of BG engineers that take a reading at boiler inlet without the thing firing is oustanding).
The main causes of an LF fault are flue mixing problems(check rubber doughnut between inner and outer flue at turret).
Condense blockages as discussed before (but if it is so bad as to cause flame failure a wee trick is to try to fire boiler up and listen to case as fan kicks in, if you hear a noise like a kid blowing bubbles down a straw into a cup then the hex is full of water)
The gas valve calibration can cause this too. Usually as the boiler cuts to low fire if water has run down the sensing pipe into governer it will cause this.
Last but not least it could be just the ignition electrode bent out of shape.
Most of these things would be easily spotted at service by an enginer that actually strips the thing to check it(i.e NOT BG)
Hope this helps