Im not familiar with this exact boiler, but i'd hazard a guess you've hit the nail on the head there. The boiler cant be firing, otherwise you'd have some heat output. Might be worth creating a new thread about your boiler, some of the more experienced boiler guys may be able to shed some light on anything you could check before calling an engineer.
I have this exact problem also, been fighting with the boiler since moving in to the house a month ago.l
We have had Scottish Gas out 4 times, and now they are coming for the 5th tomorrow.
Pressure is at 1.3 bar.
Had them replace the Ignition PCB Board, worked when he was round, now this morning stopped (after installing on 24th Dec).
I can hear the fan start, boiler seems to fire up and there is a surge of hot water on/off, then runs cold.
When power is turned on there is a burner light, its a two stage light, and goes to second stage (bright light) when you hear it initially fire, seems to fire then stop, then the light goes back to the first stage (dull light).
Possible fault with ignitors or flame sensor or electrical grounding?
There is a thermostat on the boiler, set to 5. 6 being the highest.
When running the heating is awesome, radiators scorching hot.
Could it be that the heat exchanger is blocked, as there were what seemed like small volumes of hot water passing through the pipes initially when fired up?
There is only a thermostat on the boiler itself, not in a room in the house.
Could the clock/control box be causing an intermittent fault?
Burners ignite then turn off after a few seconds
* This can be a tricky one where the problem lies in a bad ground or the the black and white wires (neutral and common wires) being reversed (reversed polarity) in either the junction box or outlet powering the furnace.
* The electronic ignition control module must ensure current flow through the flame sensor to ground and if the polarity is reversed in the circuit there is no voltage potential and the flame sensor does not work. So although the burners initially ignite the ignition control module will close the gas valve because of failure in the flame-proving (flame sensor) circuit.
* If the black and white wires are connected correctly and the flame still drops out, then the issue may be a bad ground. Using a volt-ohm meter, measure between the white wire (neutral) and the green wire (ground) to be sure you have no voltage.
* If this does not work, replace the flame sensor. See the tutorial Replacing an Electronic
yeah you may look into the small window and see a small pilot light,alight but is the main burner on,,,,sounds to me as thought the boiler is not rectifying,,,,you need an engineer all said and done. If the burner was on and the pump had failed it would overheat and something would feel hot and possibly noisy!