Greenstar 28i hot water issues

[GregA]

Hi All

I'm having problem with my Greenstar junior 28i.

When running the hot water, it cuts out after about 1-2 Mins and the boiler locks out

This happens with the heating on or not (heating is fine)

After looking at other posts on here I cleaned out the secondary heat exchanger to no avail, then as the problem persisted, thinking I might not have cleaned it out well enough have replaced it with a new one. But still the problem remains.

During these works, as the systems water was very mucky, I've also fitted a new Magnaclean filter and also ran some x800 cleaner through the system, drained then flushed it and refilled with inhibitor

I've seen people making remarks to the diverter valve assy. and flow switch, could it be one of these or possible a PCB problem?

Any gems of wisdom, greatly received!

Cheers
Greg

 

[GregA]

Just to add...after the reset button is pressed the boiler restarts and hot water available for the same 1-2 mins, then goes off again

This is repeated every time the reset button is pressed

Any ideas??

 

[AGAS]

what the lights doing on the front when faulting ? with the COVER on , you shouldn't be inside the boiler

 

[picasso]

Turn the preheat off (press the eco button till it lights up) and see if that makes a difference.

 

[GregA]

Thanks guys

Just tried the eco button long press and the button lit up

The hot water worked when the shower was turned on, and it lasted a few minutes longer than usual before lock out

Does this shed any light?

Had to rush out the door so didn't pick up on what the main light indicator was doing

Cheers
Greg

 

[picasso]

DHW thermistor at a guess.

 

[AGAS]

not just the blue light, plus see if other buttons light up as well when it faults , the frequency of light as described in manu instructions .
could be overheating but not noticing on ch maybe