Potterton Central Heating not working

[Sausage]

I have a Potterton Suprima boiler and a Potterton EP2002 programmer.
Currently the central heating will not work.
Water heating is working correctly.
When switching on the central heating from the programmer, the LED on the programmer comes on but the thermostat led (which is in the hall doesn't come on). Recently I noticed that the LED on the thermostat wasn't always coming on, but after a few tries it would light up and the central heating would come on.
I can get the central heating to work by selecting hot water on the programmer then manually overiding the valve in the airing cupboard.(slider on bottom)
Any ideas in what could be wrong.

P.S
There are 2 relays in the programmer, when I select water I can here it clicking but when I select central heating there's no noise.

 

[AlanE]

As if it is not painfully obvious by now to you you have what is refered to as a defective programmer.

The cure? Replace it.

Alan

 

[weargas]

first try switching the power to the whole thing off, remove the programmer from the backplate, re-attach and put the power back on.
sounds daft but on a few occasions i've removed this model programmer to test the wiring behind during fault finding and when i've re-attached the programmer it's just started to work. you remove it by sticking a screwdriver in the slot underneath and swinging the whole thing up and off

 

[Sausage]

Thanks for confirmation that the programmer is faulty.
I kinda hoped that this was the case but was trying to fault find down to component level.
Changing a sticking relay is more cost effective than the whole programmer.
There are 2 relays in the programmer. I'm going to swap them and see if the fault follows.

With the current programmer it does not allow you to program the water and CH to come on at different times.
There is another programmer available which will allow this.
Physically they look the same.
Is it just the case of changing the programmer?

 

[Sausage]

Just in case anyone gets a similar problem.
I swapped the relay inside the programmer and the fault followed.