Ravenheat combi boiler fails to stay lit

Hi all, I have recently installed a Ravenheat combi boiler LS-100T (ye
those cheap and cheerfull ones from B&Q) but it has a problem stay lit I have done several of these boilers in the past and had no problem what so ever, but this one just wont play ball!
When either CH or DHW is called for, the ignition sparks and the burne lites. Then after a few seconds when the spark stops, the burner goe out. Then there is about 10 seconds delay before it tries again. Thi repeats three times then the flame failure light comes on.
This problem occurs with both CH and DHW, so i dont think it will b the overheat stat coming in. I was thinking it may be the air pressur sensor if the flue has slipped out of position?
Has anyone experienced anything like this before?
Any help would be much appreciated.
Thanks,
Mark
-- MGreen
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
MGreen wrote:

Yes, it was on a brand new Baxi Back boiler, The thermocouple was waggling in the breeze. Tightened it, and all was well.
Mr Zikki Malambo DOD 6809
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 23 Jan 2006 07:32:15 -0800, zikkimalambo wrote:

I doubt this model has a thermocouple, in fact I've just looked it up and this model has a flame sensing on a separate wire from ignition.
Both my expectation and the fault finding flow chart all point to the flame sensing electrode, its wire, or the ignition board.
I have other suspicions about this installation which probably should best remain private.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.