Worcester greenstar 28i DHW not that hot until shower is turned on aswell ??

[Matt06]

Hello, Anyone got an idea what could be going on with this

If i turn a hot tap on temp is around 45C for 30-60secs, then drops to around 35C Fan speed sounds low

If i turn 2 hot taps on same as above

If i turn shower on water temp is good and fan speed is higher

If i turn shower and a hot tap on Water temp is very good for both (45C-50C constant) Fan speed is higher (Medium)

Tested and changed DHW thermistor and Flow switch as old one sounded rough when i blew through it.


Thanks

 

[bewsh]

Plate heat exchanger a bit blocked? Check the temperature difference across the flow/return to the heat exchanger to see if it's losing the heat efficiently.

 

[Ch4 plumbing]

Worn diaphragm in the diverter valve.

 

[bewsh]

The greenstars don't have a diaphragm, do they? I thought they had a flow turbine?

 

[Ch4 plumbing]

Sorry bewsh my mistake:tounge_smile:

 

[bewsh]

It's ok, just don't make the mistake again please :wink_smile:

 

[arran197]

You haven't got a crossed pipe somewhere? I had a duo tec doing something similar and the tenant had plumbed the hot and cold in on the washing machine together using it y piece. Causing all sorts of trouble.

 

[Matt06]

Thanks for all the replies, I think arran may be right I turned the cold in to the boiler and water is still flowing through the hot taps at a slower rate, Maybe some one has nt fitted non return valves to the taps which is letting half the flow through the cold and half through the boiler

 

[bewsh]

Good find. I've only ever had that once in the past. It was a fault on the mixer shower. New shower fitted, and all worked perfect.