FGA Readings - Oily question!

[dontknowitall]

I've not asked a question for ages but need some help.

I serviced a 20 year old boiler yesterday and have warned the customers (one of my regulars) that next time they should think about a boiler funeral service. In the meantime I want to make this thing run for a good six months but got some odd readings and need to know how to correct this.

I've mislaid my oil pressure gauge so will have to return to check this but boiler sounds great and the flue gas is clean (viewing and smoke test).

Last year's nozzle was quite clean (as was the one from the year before) and the readings were fine in those years. Yesterday I got:

Mistral boiler
Riello (2.2? - 1992 model)
I changed the nozzle with the same: 0.75 80 deg EH

First test produced over 15% CO2
Closed down air from 3.5 to 3 ish (scale 1-6) but the CO went to around 80ppm :redface:

I finished by adjusting the air to nearly 4 and have left the boiler until I find my oil pressure gauge.

186 degrees C
13.21% CO2
13 ppm CO
0.0001 Ratio
7.6% O2
89.2% Effn
82.1% Effg

Only other thing I can think of that might help is why I'm condemning the old girl. The customer's have been itching to have a new boiler for a while but, more importantly, the baffles are much more difficult to remove/replace for cleaning and I feel the boiler is running far too hot (metal fatigue over the years?)

So, the question is do I have to go back or are those readings sort of okay?
If it's best to return (when I find my oil gauge) what should I check/test/change?

Many thanks in advance!

 

[SimonG]

Def worth a return trip with the oil gauge, poss running a little high on the oil. At 13.2% it wont take a lot to start sooting.

I would call in next time passing and check oil pressure and adjust from there. Easier than having to de soot it

 

[dontknowitall]

Thank you, Simon!

 

[DirksPlumbing]

Def worth a return trip with the oil gauge, poss running a little high on the oil. At 13.2% it wont take a lot to start sooting.

I would call in next time passing and check oil pressure and adjust from there. Easier than having to de soot it

Very much agreed except of the fact that I would expect it mildly sooting already at 13.2%.
Maybe a good idea to have a look for a smoke pump too. That possibly would have told already.
Beautiful job to have to clean the boiler and the flue after it sooting. Gets even better on condensing models. That is usually a one job day since the rest of the day you are enjoying cleaning yourself.

Make sure before you leave this place the next time to recheck the photo cell.

By the way: I tend to find all sorts of nozzles in boilers. Quite often they should not have been used at all. Always check the MI / data badge.

 

[dontknowitall]

Many thanks for the input Dirk.

Smoke is 0-1 and no visible smoke from flue either.

What's puzzling me is why with no adjustment and having run so cleanly for the last couple of years it suddenly gives me such a high CO2 and O2 reading - and, having done so, what is causing this. (Nozzle fitted is the recommended size.)

As said, when I find my pressure gauge I'll be able to check the oil pressure as it could be the pump is on its way out.

 

[Best]

Yes, 13% is getting high. He said he had done a smoke test, so assume he used a smoke pump. When the CO2 is too high you raise the air setting to lower the CO2. Danger that someone has touched the oil pressure screw on oil pump by mistake if they previously tried to bleed the oil pump if out of oil.

 

[Best]

Many thanks for the input Dirk.

Smoke is 0-1 and no visible smoke from flue either.

What's puzzling me is why with no adjustment and having run so cleanly for the last couple of years it suddenly gives me such a high CO2 and O2 reading - and, having done so, what is causing this. (Nozzle fitted is the recommended size.)

As said, when I find my pressure gauge I'll be able to check the oil pressure as it could be the pump is on its way out.

New nozzle could be faulty! Oil pump on Riellos tend to just wear & oil pressure drops to 7 bar, which is usually just about okay on Kerosine.

 

[dontknowitall]

Many thanks Best. I've had a faulty nozzle before so I'm not discounting this but must find my gauge - I think that's 3 of us who reckon it's the pump.

I'll have a rootle (speling?) around the van over the weekend for my gauge.

 

[Best]

Get yourself a spare new oil gauge (glycerine filled gauge) for all they cost & keep it in a box with oil tools only. Its one tool you can't do without.

 

[DirksPlumbing]

Many thanks for the input Dirk.

Smoke is 0-1 and no visible smoke from flue either.

What's puzzling me is why with no adjustment and having run so cleanly for the last couple of years it suddenly gives me such a high CO2 and O2 reading - and, having done so, what is causing this. (Nozzle fitted is the recommended size.)

There is hundreds of reasons for a changed setting. You would not believe what kind of things you can sometimes find in the airway of oil boilers. Starts with missing bits of washing, animals, cob webs, wasp nests. Not to forget the all present dust in various thicknesses.

As well as a changed oil pressure is perfectly normal especially if you have changed the nozzle. That is one of the reasons why pumps are adjustable. Even a filter clean can make a difference when the pump does not need to try to suck desperately the filter including casing and sludge up the 10mm line anymore.

Up to smoke 5 I usually struggle to see even a shade of smoke in the fumes. Against light backgrounds. So I would not bank on that. Once you can see it smoking it is really bad. If you can read a 10 on the neighbours white bed sheets it is definitely time to pull the FGA out mg_smile:.