Food for thought - Worcester 30CDI

[nowucit]

The worcester training is alright. I did mine in the back of a van with boilers on jigs, the freebies are rubbish though :-(

Hmmmm ... Wonder if I can get them to come to me 🙂

 

[vern]

Serviced the above the other day which I was told hadn't been serviced for around 4 years and before that BG has done it on contract and were in and out in 10 mins.

MI states fan pressure should read negative - 3.9mb or greater, pressures measured below this figure indicate the heat exchanger will need cleaning.

Fan pressure was -5.87

FGA readings show CO2 10.1, CO 50ppm, Ratio 0.0004

I decided to give the boiler a full strip and clean anyway as I had not done one before and the CO2 was a bit higher than MI stated 9.6 max, 9.0 min.

When I opened up the combustion chamber to clean the heat exchanger the attached picture is what I found which to me looks like it was in need of a pretty good clean. Which then led me to wonder what state it might have been in if I had left it based on fan pressure or simply adjusted the CO2 levels to bring it down. I also wondered if this might be one of the reasons why some engineers are routinely setting CO2 levels wrongly as I hear on the boards.

For information, when I gave the heat exchanger a good clean the CO2 level dropped down to 9.6

Thought it might be a good point for discussion as I'm new to the trade and would value your views. Would be also interested as to the reasons why engineers are commonly adjusting levels wrongly so I don't fall down the same hole. 🙂

Hi
have you had your manometer calibrated, as the 30kw WB5 cell reads only -5.2>>-5.4 Mbar brand new, tolerance is due to voltages on boiler input and fan etc, so I cannot see -5.8 Mbar with a fouled cell!

 

[nowucit]

@vern I use my analyser Kane 455 bought new in January, assumed it would be capable of the job?

 

[vern]

@vern I use my analyser Kane 455 bought new in January, assumed it would be capable of the job?

I have a dedicated calbribated digital manometer, the Kane is just a jack of all trades as most analysers are, i wouldn't trust one on so delicate a minus pressure measurement.....

 

[nowucit]

I have a dedicated calbribated digital manometer, the Kane is just a jack of all trades as most analysers are, i wouldn't trust one on so delicate a minus pressure measurement.....

That's a good point ... MI says fan pressure should read negative -3.9 or greater how does -3.9 work with the tolerances you mention?

 

[vern]

That's a good point ... MI says fan pressure should read negative -3.9 or greater how does -3.9 work with the tolerances you mention?

Correct and it takes a really fouled cell to get readings this low, only one I had backed to a dusty farmers field/ track it was all inside the combustion chamber,.....minus 4 so I stripped it and flushed with water back upto 5 ish