Food for thought - Worcester 30CDI

[nowucit]

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.

 

[villa_tom]

Ill be honest, I wouldn't have done a full strip down service if the fan pressure was ok.

The FGA readings can be adjusted, I find most boilers require a tweak anyway.

If you had left the boiler without stripped down gas safe couldn't have done anything as you followed the MI's and did what was asked.

Youll always find problems if you look deep enough into anything.

 

[Nostrum]

Me neither, that debris looks like it has accumulated as you have cleaned the above sections and taken the picture midway through the process? Either way the fan pressure was spot on so obviously its not causing a restriction.

Engineers adjust the gas valves incorrectly because they can't read instructions properly, nothing to do with what's inside the boiler!

 

[nowucit]

Thats interesting i wouldn't have expected to find a build up of crap inside with the reading and fan pressure being what they are albeit the CO2 being slightly high.

Picture taken as found prior to cleaning. I wouldn't have stripped down based on the readings other than I hadn't done one before so a bit of hands on was really useful.

 

[Nostrum]

Fair enough, did you replace the seals as well? Quite a bit of debris there then, but not affecting the safe operation of the appliance it seems.

Readig your post again I would have recommended a strip down and seal replacement given the age of the appliance, but you couldn't do this to every appliance you meet as it'll cost the customers a fortune in new seals.

 

[nowucit]

Yeah replaced seals as per MI, was more interested in what I found compared to what MI and CPA1 calls for would have expected it to be cleaner based on the FGA readings and fan pressure given that MI suggests it doesnt need stripping and cleaning ... Just goes to show

 

[Destroyer2813]

My first question as well would of been did you replace seals after, did you have a service kit with you ?

 

[nowucit]

My first question as well would of been did you replace seals after, did you have a service kit with you ?

i did indeed as per MI instructions ... The point of the original post was more to do with what i found compared to what MI and CPA1 calls for would have expected it to be cleaner based on the FGA readings and fan pressure given that MI suggests it doesnt need stripping and cleaning

 

[neily01]

If i based my work just on the fga readings i would have prob checked gas rate the adjusted gas valve. So it seems a good idea to be able to check the fan pressures, hopefully more manufactures will take it up.

 

[gassafe]

i did indeed as per MI instructions ... The point of the original post was more to do with what i found compared to what MI and CPA1 calls for would have expected it to be cleaner based on the FGA readings and fan pressure given that MI suggests it doesnt need stripping and cleaning

do you have the cdi heat exchanger service brushe/ rasp? Or is there another way to do it!?

 

[nowucit]

do you have the cdi heat exchanger service brushe/ rasp? Or is there another way to do it!?

PMSL ... is that the one with the rasp and brush? The point of the original post was more to do with what i found compared to what MI and CPA1 calls for would have expected it to be cleaner based on the FGA readings and fan pressure given that MI suggests it doesnt need stripping and cleaning.

 

[gassafe]

PMSL ... is that the one with the rasp and brush? The point of the original post was more to do with what i found compared to what MI and CPA1 calls for would have expected it to be cleaner based on the FGA readings and fan pressure given that MI suggests it doesnt need stripping and cleaning.

I just asked because I have not stripped one yet, and wondered if a normal rasp would fit in the grooves. From your picture, I don't think my rasp would fit in there! So I will probs buy the kit, only need to buy it once I guess & there's plenty of cdi's about!

 

[neily01]

I recently started a thread about a ideal optia that had a big hole in the inner flue which was leaking all over the inside of the boiler, some how even with this big corrosion hole I was only getting about 20ppm with a 0.ooo ratio. How come it wasn't mixing and sending the analyser nuts?

 

[nowucit]

I just asked because I have not stripped one yet, and wondered if a normal rasp would fit in the grooves. From your picture, I don't think my rasp would fit in there! So I will probs buy the kit, only need to buy it once I guess & there's plenty of cdi's about!

sorry thought you were taking the **** lol ... No it's more of a cleaning blade than a rasp (as below) and the bush is very small and slim, made for purpose I suppose.

 

[gassafe]

sorry thought you were taking the **** lol ... No it's more of a cleaning blade than a rasp (as below) and the bush is very small and slim, made for purpose I suppose.

where did you get that! Worcester used to give them out on training courses, but not anymore! I got the cleaning brush for the round type in ri & si boilers but not the nice rasp blade!

 

[nowucit]

where did you get that! Worcester used to give them out on training courses, but not anymore! I got the cleaning brush for the round type in ri & si boilers but not the nice rasp blade!

Is the Worcester training any good?

 

[nowucit]

I recently started a thread about a ideal optia that had a big hole in the inner flue which was leaking all over the inside of the boiler, some how even with this big corrosion hole I was only getting about 20ppm with a 0.ooo ratio. How come it wasn't mixing and sending the analyser nuts?

Sounds like what it is picking up is diluted POC maybe because it was pulling up air from the boiler into the exiting POC giving you a low reading.

Did you find out from your original thread?

 

[neily01]

Got call there originally because bg turned one of the two off because of water leaking all over components. Found the fault replaced parts all good but combustion not much better, but can't get much less than 20ppm.

 

[villa_tom]

Is the Worcester training any good?

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

 

[nowucit]

Got call there originally because bg turned one of the two off because of water leaking all over components. Found the fault replaced parts all good but combustion not much better, but can't get much less than 20ppm.

20ppm doesn't sound bad which is why I thought it was low rather than high ... What were the other readings ratio and CO2, don't think I've seen CO as low as 20ppm on anything I've looked at

 

[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