Worcester 18/25 combi hot water probs

[BoilerBob]

Well my customer phoned and told me the thermostat I fitted hasn’t cured the hot water problem. Seems he only gets a bowlful before the water goes cold, now I’m thinking flow switch anybody got any thoughts. Bob

 

[Burnerman]

I think the boiler should fire up the minute the hot tap is opened, and stays that way until demand stops so the flow switch sounds a likely culprit. If he has heating just now the pump operation sounds ok.
John

 

[oilhead]

On these later models, if the heatstore is up to temp, the burner does not fire until the DHW stat calls, but the pump should run and diverter valve operate from the CH mode. There is always the possibility that the heat exchanger is scaled up and after the initial discharge it does not have the transfer capacity. Compare hot and cold flow rates. Also, what flow rate are you looking at?
Have I missed some posts? What stat did you change?

 

[Terrywookfit]

Plate H/E blocked on primary.??
Divertor ??
Is Tmv fitted ??

 

[BoilerBob]

The Dhw stat on the control panel as the heat store seemed to getting cold
so it was changed I checked it and all was getting hot but customer phoned tonite and said it wasn’t working, so I’m thinking flow switch now. Bob

 

[BoilerBob]

There is a good flow from hot tap so I’m thinking it could be primary or flow switch