What can cause this?
The system shuts down nicely at 11pm as per the timer.
We go to bed.
No one runs a hot tap.
At 3am I see that the system is in lock out mode.
The timer is not set to fire up the central heating until 5am.
What? Why? Where? How? I'm foxed.

Rob, April 2009

Possibly solved - fingers are crossed.
Our plumber rang glow worm again - he got a different bloke who straight away said that it was due to the replacement pcb being faulty.
It seems it is not uncommon for new pcb's to be faulty when they leave the factory!!!!
This necessitated another new pcb and some other new (for the 2nd time) electronic gubbins that the faulty (yet new) pcb would have broken.
Things are OK up to yet - but it's only been 2 days - it has worked before for a few sessions then broke (as it is summer - we aren't really using central heating).
Cheers.

Rob (original poster)., July 2009

That didn't seem to work.
How long are new boilers supposed to last?

Rob (original poster), May 2009

Nice one Nick. Thanks for sharing.
Our guy has recently seen the problem for himself.
He noticed that a fan wasn't kicking in when it should, so greased that. He's coming in tomorrow to have a read of your message.
I'm sure he'll get there. I'll add our solution when we know it.
Thanks again.

Rob (original poster)., May 2009

Rob dare I say it I think it is fixed! Had another Glow Worm engineer out Thursday (7th May) and changed/cleaned (new diaphragm) some diverter switch that was sticking and hitting a micro switch! That was caused by central heating system gunge!
Part numbers s801191, s801199 and s801201 ask your plumber as you can tell I don't know what I am talking about.

Nick, May 2009

Hi Nick.
No it isn't fixed yet - today = 3rd May 2009.
We reported it about a week ago and our engineer has been looking and trying things off and on for a week.
I think he's on to something re switching the timer feed to off - but that hasn't really cured anything (but it is a good lead). I ust hope it's not a red herring.
He's rang glow worm - they were foxed.
The trouble shooting guide just says to hit reset (that'll be no good at 5am in December!!!).

It'd be great if anyone who has suffered this could list what the solution was.

Cheers.

Rob (original poster)., May 2009

Rob have you had this fixed yet? I've got the same problem. Had two engineers out (one from Glowworm) test boiler and they say it is fine. An hour later it is locked out!

Nick, May 2009

Thanks for the response.
We've got our regular engineer in.
They're very good - but right now they are foxed and so are glow worm. Hence I'm posting here.
PCB has been changed - and other things.
I was hoping someone may have experienced exactly the same thing.
One thing we have learned - if we switch the central heating off at the timer control - that is to say it totally ignores the programming - then in the morning it has not locked out. But as soon as a demand is put on the system for hot water - it locks out.
I reset it and it then works straight away.
All was well about 9 days ago - then - pow.

If anyone has experienced this - it would be great to hear what fixed it for you.

Rob (original poster)., May 2009

Sounds like you need a registered Engineer (www.gassafe.co.uk0 will help,

Could be faulty Pcb, or just a short on the Electrode or connecting lead, but without seeing the installation is very difficult to comment

www.elanar.co.uk, May 2009