Worcester 9.24 RSF electronic, Advice please

[TFGplumbing]

Heya guys

Basically I got called out to a Worcester 9.24 RSF electronic, Its was firing on the CH But not on HW, So I looked to the diverter Valve on it And sure enough the spindle on it was stiff and it was not pressing the microswitch when a hot tap was opened, I removed it and replaced it, The old one was internally full of scale.
I also replaced the expansion vessel(old one full of water diaphram split) and AAV(old one not working). So I reassembled the boiler Only to find that the same problem persisted, The boiler fires when put on CH mode but when a hot tap is opened It doesent even go through the ignition process, And also for example if the CH turned on and running and you opened a hot tap it will turn it self off (kill the burner)

Iam going to phone Worcester today but, Iam thinking that the over heat stat has proberly popped what do you guys think? (its a not resetable one so it will need replaceing)

Any help greatly appreciated thanks

TFG plumbing & Heating

 

[wazzer]

If the over heat stat was faulty it wouldn't work on CH...........Let us know how you get on

 

[nysk2008]

do what a large gas company do - recommend a powerflush

 

[ccc]

check if micro switch is making then check switch with multimeter if ok check pcb board ign buard

 

[TFGplumbing]

A stat spade connector had been disconnected from the hw outlet pipe inside the boiler, i must have pulled it off when i was changing the diverter valve, ITS WORKING!!! My customers were so happy that they had hot water again!!!