performa 28 no heating

[Type R]

I have a potterton performa 28 which the heating side will not work. It was working fine last week but now it will not heat the rads.
When the switch is turned to hot water and heating not even the light comes on for the heating, also no matter were the time clock is set ( on or off) the boiler will keep lighting as if you have set it to come on.

Potterton told me it was the PCB so that has been changed but it is still the same

please help

 

[namsag]

Have you checked the clock is giving out power and it is actually going through room stat back to boiler.
What clock and what room stat do you have

 

[Type R]

It's a combi boiler so the clock and stat are built in

 

[namsag]

Just re read what you put when it keeps firing is the hot water demand light lit.
Even though a tap is not on

 

[Agile]

I think that if the diverter was stuck in the DHW position it would give the problem he seems to be describing. That would be pretty unusual though.

I would be asking if the diverter valve pin extends and retracts when DHW is demanded.

Tony

 

[Gasguru]

Is the hot water demand light on? despite the hot taps being closed.

 

[Type R]

yes the hot water light is on and the boiler firers up even when it is switched heating but the switch does say heating and hot water or just hot water.

The central heating light doesn't light up even when it is asking for it

could it be the the primary flow valve diaphragm damaged or the 3 way valve damaged or blocked but there again why does the central heating light not light up?[/quote]

 

[Type R]

Is the hot water demand light on? despite the hot taps being closed.

no it is off

 

[Gasguru]

You're confusing me now.

When the hot water taps are turned OFF is the hot water demand light on the boiler either ON or OFF? ie does the boiler think there is a hot water demand despite the taps being turned off. Forget the mode switch setting.

 

[Type R]

You're confusing me now.

When the hot water taps are turned OFF is the hot water demand light on the boiler either ON or OFF? ie does the boiler think there is a hot water demand despite the taps being turned off. Forget the mode switch setting.

yes it is on

 

[Gasguru]

Open the front panel - screws either side. Look at the circular brass lump on the left. There will be a pin protruding from the centre and a switch in front. If the pin is retracted (ie not touching the switch) the switch could be faulty but if the pin is extended the diverter is siezed. I'm assuming although the boiler indicates a hot water demand there isn't a water leak on your hot water pipes (say under the floor).

 

[Type R]

No water leak so i will check the pin when i get back home

cheers for the help

 

[baxpoti]

Try turning the cold supply feed to the boiler off.

Is the hot water light still lit?

 

[Type R]

with the water supply off the light doesn't come on

 

[baxpoti]

With the cold feed off does the central heating work?