28i greenstar junior lockout

[pipefitter]

A bit of advice needed please ,been to look at a greenstar 28i junior & it is locking out in heating mode only ..hot water mode is fine .
Flue is ok , condense pipe is clear ,inlet pressure is good 22mb & getting a 2.5mb drop when running at full load ...
It runs for about a minute or 2 then lockout ,I'm getting light normally off then blue flash which indicates ignition lockout,but why only in heating mode?
Keeps going to lockout until its cooled down(5mins) then it lets me reset it
I've left it with heating switched off & it's running fine ( hopefully till Monday)

 

[Dotty]

You need a gsr in to look at your boiler. We cannot and will not give advice on the installation or repair of boilers for your own safety.

Please go to Gas Safe Register | Ensure your gas engineer is registered. or post a thread in the 'I'm looking for a plumber / gas engineer' section of these forums remembering to include your location. [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL]

If you are gsr please increase your post count to 10+ then send a pm to either Gas man or Redsaw who will then check you and then give you access to the gsr private forum.

Thank you.

http://www.ukplumbersforums.co.uk/central-heating-forum/42241-notice-gas-safety-related-advice.html