Very very Hight Co2 ppm old Myson velarie... Help

RayPlumb · Jan 4, 2019

Got called out this morning to a lock out boiler. . Myson Valerie 50/70 At first look it sounded like motor stuck. I checked fan moving freely, pump a little resistance but seemed ok. When fan removed it started slow but ok. my thoughts were capacitor. original one was 3UF. I had an old 3uf and same struggle to start fan. I had a 4.5UF . I put that in and stared no problem. Then client asks if i can service it. I give chamber a goo clean etc . New nozzzle . I have no manufacturers guide so previous plumbers service was 0.60 / 80 deg/ EH . so copied that. Put pressure tester on pump and pressure stuck on 90 psi. When I tried to adjusted it it leaked from the pressure adjuster, and wouldnt move from 90 psi (bfp21 l3). So off to merchant new pump. changed pump . pressure set at 115psi (as shown in previous plumbers test sheet).
Done smoke test about a 2. added a bit air to get a 1 smoke test. then put analyzer in and COPPM started shooting up 6-700++ I pulled probe out quick. ..
I then checked baffles and all ok . changed the nozzle for a 0.5/ 60/ES
and same again. I pressed save an analyzer before pulling out and get 12.2 02, 6.5 %co2 , 810ppm, flue temp 127 deg, Exess air 140%. The air intake is almost closed..
Does the capacitor have any influence on the fan speed or is it just a kick start?,, could too much air push co ppm up that high. ?
Any one have a recommended nozzle size for this boiler as a start.?
I then switched boiler off and told client not to use until sorted and safe.
Any ideas where I went wrong..?
Thanks

Christopher buzzard · Jan 4, 2019

What make burner is it?

RayPlumb · Jan 4, 2019

not sure before my time. Could not see any names it is Orange.. looks same as this pic

bacon_sandwich · Jan 4, 2019

I suspect that capacitor is a "run" capacitor rather than a start capacitor, if it is different than yes it can affect its performance, always making it worse. Your readings are at least in the "zone" apart from CO, lol so i suspect its more of a tweak to get it acceptable. Try the right size cap first, i dont do oil.... is that temp in the range ? as i would have expected north of 150 degress.

RayPlumb · Jan 4, 2019

temp is a bit low on 130 on quick test test then 180. would expect 210 +/-
how do you tell if you have or can order a run capacitor or start capacitor... I suspected the fan was running faster with the new capacitor, but then I thought it was new pump with less resistance.

kris · Jan 5, 2019

kris · Jan 5, 2019

kris · Jan 5, 2019

That's out of the instalation manual . I tried to upload but it's through GIW ( gas installers workmate) an app I use for boiler manuals but it won't let me . Hope the pic helps

RayPlumb · Jan 5, 2019

Thanks Kris . Ill cherish that. Ill up pressure to start with..

Best · Jan 5, 2019

I have the manual for the Myson Velaire boilers.
That burner is the old Electro oil Swedish burner and is a superb burner.
It should be easy to set up.
I assume the nozzle assembly has not been tampered with?
You either have a faulty new nozzle (unlikely) or the motor is knackered.
The capacitor should not make any difference to that motor functioning once it starts.

Best · Jan 5, 2019

RayPlumb said:
Thanks Kris . Ill cherish that. Ill up pressure to start with..

You don’t need to up the oil pressure to achieve combustion on that burner.
100 psi will even be fine, although it probably should be 120 at least.
Something else is badly wrong.
Edit, - 150 psi is too much, despite it being on an old specification that Kris has kindly put on.

Best · Jan 5, 2019

RayPlumb said:
not sure before my time. Could not see any names it is Orange.. looks same as this pic

View attachment 36172

Just suddenly realised you said burner is orange in colour!
The air “door” on the orange burners is a round piece of metal band that is adjustable by a bolt and is a stupid idea because it can block with dust where it gradually tightens.

RayPlumb · Jan 5, 2019

Yes and a thin threaded adjustment shaft to adjust with. I think im going to order 3uf capacitor and have another look another look Monday. Just feel bad about leaving with no heat..

RayPlumb · Jan 5, 2019

Best said:
I have the manual for the Myson Velaire boilers.
That burner is the old Electro oil Swedish burner and is a superb burner.
It should be easy to set up.
I assume the nozzle assembly has not been tampered with?
You either have a faulty new nozzle (unlikely) or the motor is knackered.
The capacitor should not make any difference to that motor functioning once it starts.

If the pump is knackered would it not spin less or could it spin more. The client says it is a lot quieter now. And it does sound ok. Is it normal for start up sequence to be.. fan spark then at start 4 second later coil and ignition. Aftet 10 seconds electrodes go off. The nozzel sits about 4mm below blast tube.

RayPlumb · Jan 5, 2019

The nozzle assembly on these burners. Do they have an air diffuser? One i changed straight shaft with nozzle at end held central by a ring bracket off blast tube.

bacon_sandwich · Jan 5, 2019

The capacitor is "tuned" to the windings of the motor. Its the way you get the right phase of magnetic field to make the motor turn. I would always replace with exactly the same spec of capacity, including material type and voltage spec. Its not going to run faster on full load but may run more erractic. When you close off the air it reduces the load on the fan, if you open the air to max, that will give you a better idea if the fan can work OK. Its not a huge difference in size of cap, but i would not do it as it may causes premature fan failure later down the line. Hope this helps.
The reason i believe its a run capacitor as its very low in value, start capacitors are much much bigger, plus a fan has so little load at rest that it can start without a start cap. I order Caps from RS components, they have loads of them

Best · Jan 5, 2019

bacon_sandwich said:
The capacitor is "tuned" to the windings of the motor. Its the way you get the right phase of magnetic field to make the motor turn. I would always replace with exactly the same spec of capacity, including material type and voltage spec. Its not going to run faster on full load but may run more erractic. When you close off the air it reduces the load on the fan, if you open the air to max, that will give you a better idea if the fan can work OK. Its not a huge difference in size of cap, but i would not do it as it may causes premature fan failure later down the line. Hope this helps.
The reason i believe its a run capacitor as its very low in value, start capacitors are much much bigger, plus a fan has so little load at rest that it can start without a start cap. I order Caps from RS components, they have loads of them

I haven’t much of an idea about motor types, as not a spark, but all I can add to that is those motors on the burner can be started by hand and will work fine until they have to stop and start again.
The OP said he changed the oil pump, so I assume the motor might be faulty and is very little money (comes complete with capacitor)
But I think the air is set too high and that is the first thing to check.
On those burners the air should be shut down to lowest numbers of approx 2 or below I think.

Best · Jan 5, 2019

RayPlumb said:
The nozzle assembly on these burners. Do they have an air diffuser? One i changed straight shaft with nozzle at end held central by a ring bracket off blast tube.

I would be concerned that the boiler is running quieter because that could mean it is sooting.
Your blast tube will be one piece type.
The air setting is far too high.
You should have used a smoke pump and lower the air setting until the boiler can still work ok still with close to zero smoke reading.
The CO2 should then be the reading to alter to achieve about 10% and no more than 11% on that

bacon_sandwich · Jan 5, 2019

Dont know oil, closest to that for me is Riello burners and their knockoffs on NG
Sometimes i am so far out, i cannot even get it to start, he has it starting and has some readings so by trial and error he can tweak it. I was also think too much air but he has air closed right down, very confusing.

Best · Jan 5, 2019

bacon_sandwich said:
Dont know oil, closest to that for me is Riello burners and their knockoffs on NG
Sometimes i am so far out, i cannot even get it to start, he has it starting and has some readings so by trial and error he can tweak it. I was also think too much air but he has air closed right down, very confusing.

Yes, I think the OP has been thinking parts are faulty, rather than working on the air setting.
The air adjuster on those old orange coloured Electro oil burners is very misleading as it will look like it is near closed off with it being a metal band, but it actually could be still allowing a lot of air in.
The motor on oil burners turns a fan and the oil pump, so can be under load with oil pump as they can be tight to turn.

bacon_sandwich · Jan 5, 2019

ahh didn't know its the same motor that runs the pump, still the cap value is so low it must be the run cap. single phase induction motors need a cap, some have a start cap and a run cap, some just a run cap.

SimonG · Jan 5, 2019

Capacitors a start capacitor. Other than change a nozzle the black silver and orange ab burners I tend to leave alone.
Far too much air. Oil pressure about 115 psi maybe a touch higher.
Check the nozzle is in properly and tightened up.

oilmark · Jan 6, 2019

I find the air settings on the aluminium band very sensitive to adjust. Like Best says they collect dust and fluff, make sure that's cleaned off. Could air be entering elsewhere?
There should be an air diffuser around the nozzle.

RayPlumb · Jan 6, 2019

oilmark said:
I find the air settings on the aluminium band very sensitive to adjust. Like Best says they collect dust and fluff, make sure that's cleaned off. Could air be entering elsewhere?
There should be an air diffuser around the nozzle.

Thanks. Im going to check to see if air getting in somewhere else, and clean band. Tell me more about the air diffuser. There definitely was not one there. How much difference does it make.? Is it something i can make without or do i need to make one up..washer.. what sort of diamiter . Would one work from another burner. .?

RayPlumb · Jan 6, 2019

Just stumbled across this . Looks like my troublesome burner. Cant see a diffuser washer behind nozzle on it or am i mistaken. Is this the same burner for myson valarie ..?

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Very very Hight Co2 ppm old Myson velarie... Help

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