Worcester greenstar 28i hot and cold

[henry nicholson]

Hi all
Our greenstar 28i is warming up then cold and takes ages to warm up again just to go cold again. If you run shower or taps on really low flow then maybe it’ll keep hot…
We had this problem last year. I was going to change the heat exchanger plate.. I flushed the system first with cleaner then got a plumber in to change it. But he started by servicing it and changed the baffles in the main bit as they’d burnt away strangely, and it seemed to be working…

but it’s started again. When we first noticed it went cold I checked boiler and the pressure was right down so topped it up but it’s still going hot and cold.
So my question is.. should I change the heat plate this time? Is this a good candidate for this fault? Maybe by flushing the system last time I cleaned it out just enough to work?.. could the diverter valve be something that’s wrong. Maybe I should change both whilst I’m there?
Any thoughts!?
Thanks

 

[kidgreen61]

Change/clean plate hex

 

[pimpdaddydog123]

Very probably the plate heat exchanger and and as far as I recall it’s quite a difficult job on that particular boiler.

 

[henry nicholson]

Thank you very much guys. Ordered the plate, replaced… and the hot water is restored! was actually quite an easy job, watched a quick YouTube video.. dropped it down the back after removing the hot water outlet. Didn’t take too long and really chuffed I shorted it without expensive charges.
thanks again!