worcester cbi 14/19 problem

[moogwai]

Lads....went the above boiler last week which wouldn't fire...followed mi's flow chart which led me to the aps...changed the aps and it worked inetermittantly, can hear aps clicking but no ignition. I took out the fan and gave it a clean made sure venturies were clean...put it back in and it worked so i left. Had a call to back today to find it's still working intermittantly and when it does fire the ignition is slightly explosive.....could this be an ignition problem? if so should i be looking at replacing the pcb?
any help would be appreciated. pm me if you like.

[fixter1]

check gas valve for let by,,, also spark gap

[moogwai]

just got back from it again....worked first time when i called for heat....worked for a while up to temperature...cut out and never came back on. So i took cover off combsution chamber checked electrodes went through start up process with gas off...spark was present on around 10 times of asking. Cleaned electrodes checked the gap...put it all back together....worked fine so i left.
Just had a phone call....not working again!!! aarrrggghhhh!!!! this is really doing my head in!!

[quality]

I know you said you checked the fan but they are notorious for running slow when hot
Maybe drink some free tea while it reachs temp next visit

[moogwai]

I know you said you checked the fan but they are notorious for running slow when hot

do they?? i'm at my wits end...how can i check if it runs slow when hot?? i don't think i could tell by eye. if this is a common prob then i'm just gonna renew it.

[quality]

Use a multimeter to ensure the aps is satisfied

[fixter1]

have you check flame sensing is in the correct position ive had one what was moving ones heated up and shut the boiler down

[moogwai]

thing thats getting me is that the fan still runs and runs (don't go into lock out) and even when the boiler has cooled it wont re-ignite itself unless i fiddle around with it!.....bloody bleedin thing....will have to spend an hour there with worcester tech on the phone.

[fixter1]

nightmare let us no the outcome moogwai

[quality]

Yes they do your box in jobs like these but at least you get a free lesson from them

[diesel_ltd]

possible gas valve problem have you checked the resistance on the coils? worcester tech will tell you what it should be... also check your thermister if its not coming back on after it gets to temp good luck mate keep us posted

[moogwai]

going back monday to see what worcester say when i'm in front of the thing!!! will let you all know.

[raymondo68]

Have you checked for a flue restrictor plate? From memory these boilers had a restrictor that had to be fitted for a certain length of flue? Just a thought.

Raymondo

[moogwai]

Have you checked for a flue restrictor plate? From memory these boilers had a restrictor that had to be fitted for a certain length of flue? Just a thought.

Raymondo

i havn't checked to be honest....all worked up until a couple of weeks ago and the flue goes straight out of the wall so i don't i don't think any thing is wrong regarding the flue.

[SimonJohns]

There is also a ot stat that is self resetting. Maybe that is failing early

Check continuity when hot