No hot water on Potterton Performa 24

[alan999]

Hi. Can someone help me with the above.
The Potterton Performa 24 combi boiler is about 8 years old. The central heating works fine on its own. However, the hot water will only work for about 15 seconds and then the burner turns itself off, so very little warm water arrives at the tap, which continues to run cold. The plunger from the divertor valve remains out and the microswitch remains activated.
If the central heating is on at the same time that will also turn off after 15 seconds.
Thanks in advance.

 

[Boilerman2]

Assuming that the burner high & Low gas pressures are correctly set I'd change the Thermistor and see where you go, A RGI would need to check the gas pressures - I have had to down rate these boilers slightly on hot water where flow rates are low, to stop this from happening

 

[alan999]

Thanks for your prompt response Boilerman2. I will get the pressures checked and change the temperature sensor and the safety thermostat. I will let you know how it goes.

By down rate these boilers do you mean set the max and min gas pressures to the lower permitted reading of each one?