any alpha specialists ?

[rab250]

Been asked to have a look at an Alpha cd30s LPG boiler the other day that was locking out on startup. anyway after getting the boiler lit after a few resets i proceeded to check the pressure differentials for the burner pressure and they were way out also i stuck my fga in the sampling port and the co went to -OR- after quite a while trying to set the boiler up and checking the air sampling port ( which had 500ppm co ) i decided to change the flue and flue top seal.
I can now get the settings bang on on low ch which is .30 differential and 10%co2 and the fga readings are good too .0008 ratio, But as soon as i crank up to the ch max which is 4.16 differential the c0 goes through the roof. I feel as though somewhere the air/gas ratio is being affected but i dont know these boilers well enough and technical support have'nt been much help.
I am now at a loss with this boiler and anything else would be just throwing parts at it until its fixed which is something i dont like doing so i was wondering if anyone actually knows these boilers inside out that might have a valid suggestion.

 

[Billy Bob Bob]

have you checked the basics,not familer with lpg,but with ng,and especially pre mix burners low working pressure will send the fga readings nuts

 

[Nostrum]

whats the XS air reading on min?

I had a similar issue with a junior the other day, who ever was last to tinker with it had set it up completely wrong and it wasn't even firing on MIN. In the end I phoned Worcester technical and they were able to give me reset values for the gas valve and I managed to get it back spot on from there.

 

[villa_tom]

I'm sure there's a bloke on here called alpha man.

 

[Billy Bob Bob]

I'm sure there's a bloke on here called alpha man.

there is tom ,not been on here for a while though

 

[stevetheplumber]

might be worth a pm as it will email him

 

[Billy Bob Bob]

might be worth a pm as it will email him

good point steve

 

[rab250]

Thank you all for the suggestions. I have Pm alphaman and hopefully he will get back to me.
Gas man that is a good point about the working pressure it was down but i didnt know that it would quite so drastic effect on the fga readings. this could be my first port of call tomorrow morning