Problems with my Sigma

[Iaindhill]

Dear All...Please can i get some help!

I have a Feroli signma 60 boiler (gas). I have just switched it on today after it being off for 6 months during the summer. electric and gas supply not turned off though..the boiler just not used.

The problem is that the boiler fires up and then cuts out after a second or two. However if i remove a screw or two from the "airtight (inner) casing" thus letting in some air the boiler fires up and continues as good as gold.

When i switch the CH or HW on the fan starts as does the water pump, there is a spark as there is initial ignition then nothing more with regard to the boiler


I have checked the resistance of the gas valve and these are 1500 ohms and 2900 ohms (approx)

On the air pressure switch (with electric connections off) there is no continuty bcontinuity and NC but 200 ohms between C and NC. contacts but the the boiler it seems. instantaneously



Any ideas

Iain[/b]

 

[ChrisR]

Your last para doesn't make tooo much sense , but the air pressure switch sounds dodgy.
"if i remove a screw or two from the "airtight (inner) casing" thus letting in some air the boiler fires up"
That's a pretty reliable sign that the fan isn't operating the pressure switch properly or the flames are being starved of air. In a normal service the fan should be cleaned which may fix it. Or the APS as I said. FLue installation problems can sometomes not show up for a long time, until things get a bit tired. This could be a case if the flames are affected.

 

[bripl]

could be a fault on the fan venturi ferrollis are prone to this

 

[ChrisR]

Yeah you reminded me - a tiny bit of misalignment and the're dead. The tubes should also be cleaned at service time of course.