Potterton 24 HW running hot /cold / hot

[gwbrighton]

I've got a problem with my Potterton 24 combi boiler.

When I run any of the hot-water taps, regardless of flow rate, The water runs to temperature, but within about 10 seconds of reaching it, runs cold. (Burner off, fan still running). About 10 seconds later burner comes back on and the cycle begins again, hot, cold, hot, etc.

Water pressure and general flow rate are normal, Seems to be running at normal temprature. Boiler has only been installed about 2 years.

Any ideas?

TIA

Gareth

 

[drbagiva]

Sounds like the plate heat exchanger may be blocked.Either on the domestic side by limescale or on the heating side by system debris.Suggest you call Heateam!

 

[drbagiva]

Sounds like the plate heat exchanger may be blocked.Either on the domestic side by limescale or on the heating side by system debris.Suggest you call Heateam!

 

[TheIce_Man]

could be the hw thermistor faulty , you could unplug the lead from the chtg thermistor and plug in the lead from the hw thermistor into the chtg thermistor and see if the water improves , if it does then it is the thermistor,you do not say if the heating is affected?

 

[gwbrighton]

could be the hw thermistor faulty , you could unplug the lead from the chtg thermistor and plug in the lead from the hw thermistor into the chtg thermistor and see if the water improves , if it does then it is the thermistor,you do not say if the heating is affected?

Thanks Ice_Man, thermistor it was. Part replaced and all is working fine.

Much appreciated

Gareth