Greenstar 28i junior DWH problem

[Darren Jackson]

Hi, I have a Worcester greenstar 28i Junior combi mk111, that works fine in CH mode but locks out in DWH after 1-2 mins, Slow Flashing blue (light mostly on) with flashing reset showing, I have re pressurised the expansion vessel as it was flat and Pressure is reading about 1.2bar now and holding. The fan was pulling minus 1.2mbar, so cleaned out the hex including the burner and it is now pulling a healthy minus 7.2mbar, there wasn't much left of the electrodes when I took it out to clean the hex. So I fit new ones along with a new seal of course. But alas still locks out under DHW demand. changed the high limit stat still no joy. No water leaks. wiring harness and connections are good and pump runs good with no unusual noises and the flue is clear. So I bit the bullet and changed the control board... Guess what... still locks out when hot tap running. So if anyone has any suggestions I would love to hear them. (me thinks maybe plate exchanger now)??? after that I,m stumped.

 

[quality]

You will need to give a mod your gas safe details for any response

 

[Darren Jackson]

Ok thanks, how do I do that. (new to this).

 

[rpm]

You will need to give a mod your gas safe details for any response

Welcome to the forums Darren, rules say first you need 10 non spamming posts on different threads which is easy then your post will be answered in the gsr forum away from public view to stop any DIY hero having a go.

 

[Darren Jackson]

My Gas safe reg number is 208346 and my licence number is 3842031 if that helps?

 

[rpm]

http://www.ukplumbersforums.co.uk/new-member-introductions/59145-how-get-started-ukpf.html

Have a look here mate.

 

[ShaunCorbs]

And for our records how did you become gas safe short course or apprenticeship ?

 

[rpm]

And for our records how did you become gas safe short course or apprenticeship ?

Is this a trick Q Shaun, don`t recall others being asked but could be wrong of course.

 

[ShaunCorbs]

Is this a trick Q Shaun, don`t recall others being asked but could be wrong of course.

Just gives us an idea how far indept/ explanation we need to give eg like step by step etc

 

[Darren Jackson]

Apprenticeship