Worcester Greenstar 30 Cdi Combi loss of CH & HW -overheating

[Dave 123]

Hi all,

12 year old boiler, regularly serviced working fine, then wife turned on hot water and it stopped working. Same then with CH. Left it for a while worked and then stopped again. I looked at it when got home and when run water boilersstarts up, temp rises and then it cuts out. Same with CH. Reset and same thing happens
Plumber came round checked pump - working, he fiddled around and worked that night and didn't in the morning - same problem.

He spoke to Worcester who advised new Pcb - replaced today and still no joy. Then advised to clean system, using X800. Currently trying to run through CH system - CH runs for about 3 mins until temp gets to 70ish degrees and cuts out, cools to 30 degrees and starts up again. Repeat ad nauseam. Can get HW now but only if not too warm.

Any advice/insights for an increasing cold family would be greatly appreciated.
Cheers

PS Forgot to say upstairs rads are warmish at the mo, ground floor tepid and basement stone cold

 

[ShaunCorbs]

It sounds like the pump isn’t 100% tbh the pcbs are pretty bullet proof I change a few pumps a year

 

[king of pipes]

Your pump is the heart of the system if it's failing then it would cause the problems you are experiencing. Kop

 

[Dave 123]

It sounds like the pump isn’t 100% tbh the pcbs are pretty bullet proof I change a few pumps a year

Hi, thanks for your prompt reply.
I've now got a new pump, but all the online instructions i can find only refer to replacing the pump head. Would i be right in assuming this is the only bit i should replace or should i be replacing the plastic assembly at the back that connects to the rest of the boiler as well? Obvs replacing only the pump head seems a lot easier than replacing the whole thing.
Cheers

 

[ShaunCorbs]

Yes you can replace just the pump head

 

[Dave 123]

Yes you can replace just the pump head

Thanks