Faulty Saunier Duval Thema Classic boiler

[Carito]

Hi there - I am new to this forum lark, so not sure Im posting in the right place. I have a 6 y/o Saunier Duval Themaclassic F30E combi boiler which is playing up. Even though I have set the timings to ----- so that the heating does not come on, and have set the setting to 'summer' which should prevent the heating coming on, for some reason the radiators are coming on of their own accord throughout the day. I have checked the thermostat which I have set to zero, so I cant see why this is happening. It seems as if everytime I run the hot water, my radiators are heating up.

Can anyone give me any advice on why this would be happening?

Many thanks,
Carito.

 

[Jordon]

Sounds like the diverter in the boiler is stuck or the moter is shot.

 

[BGcangodie]

Just clear something up for me please mate, from your question it sounds like you are having 2 problems?

1. boiler firing intermittenly with no demand on CH

and

2. radiators heating up when the DHW is running

If you are getting both of these then as Jordan says for the radiators getting warm when ruuning DHW then the divertor is passing into the heating system.

As for the intermittent CH (if this is happening) then you want to be looking at your ext controls as one possibility, you will have a small credit card sized PCB in there the 230v control board, On that board you will have a small green(or orange) block on the face with 3 terminals. If you catch it running a CH demand with your controls off then go from the middle pin to earth (this is your switch live) on vac, if you are getting voltage there then your ext controls are still calling so its an ext control fault, if no voltage there then more than likely you are looking at a fault with the 230v control PCB, there are some other tests you can do but if you want, if you dont get voltage on the switched live then write back on this forum post and i will assist you with the further tests to rule out the main PCBand the 230v control PCB.