Soot Issues on brand new furnace

m1tchsc0tt0

Hi All,
I recently had a new oil fired furnace Granby Conforto KLF-200 with the becket afg burner. The problem is it seemed like it was fine during the winter but now that its gotten a bit warmer I am noticing soot specs accumulate on the outside of flue piping after the furnace running. I can blow it off the pipe and then it seems like its comes back. The house is a two story colonial and I never had this issue on my other furnace 10 year old armstrong, so I don't think its a chimney issue. At this point after adjusting the burner a few times the installation tech's next recommendation is to install a ouside air attachment for the burner. That seems kind of strange to me considering that the house is old (built in 1951) and I would be surprised that the basement is that air tight where fresh air is an issue? The house has 2 other fireplaces but none have been in use since the furnace was installed. Anyone have any recommendations / thoughts?

Thanks!

pecmsg

Is there a piece of paper with the Combustion Analyses #'s on it?

STEVEusaPA

It may simply not be set up right. May be a lack of draft. Could even be the draft regulator in the wrong space, no pre purge, etc.
Got some pics?

MaxMercy

Probably not your issue, but be aware a brand new furnace can soot a minute after it's installed and properly set up. Happened to me. About 5 minutes after she was running smoothly as silk it suddenly started to rumble badly, and the flame was impinging so badly on the back target it actually curled around and made it back to the burner head. The brand new nozzle on the brand new AFG decided to fail. A new nozzle and a new setup and back in business.

What I don't get though is the soot accumulating on the *outside* of the flue..

m1tchsc0tt0

yeah attached.

m1tchsc0tt0

Also attached here pictures of the soot specs on the outside of the flue. they are little dots that accumulate on the outside. kind of hard to see in the pictures.

heathead

How much clearance is there to service the burner? What do the installation instructions say. That looks very tight and not very good for future service?

MaxMercy

heathead said:

How much clearance is there to service the burner? What do the installation instructions say. That looks very tight and not very good for future service?

Hard to believe that orientation was the best they could manage. I would have turned that thing 90* at least.

Jamie Hall

At the risk of a silly question... how do you pull the burner for service?

m1tchsc0tt0

Not sure about how to pull the burner I believe there is enough room to get it out as they claimed they have checked the nozzle etc. Also according to the documentation it needs 2.5" clearance which there's about 6. But I am by no means knowledgeable in this field.

mattmia2

What is on the ceiling above? Perhaps they knocked something loose when they replaced the furnace (or perhaps the vent is too close to and is burning something)

m1tchsc0tt0

nothings above the ceiling just subfloor and the duct work.

EBEBRATT-Ed

@m1tchsc0tt0

Your burner is not set up properly. Your Co2 reading is too high the burner is not adjusted properly and needs more air. You need a new service tech as the problem is as clear as a bell.

Co2 should be 11-12%

STEVEusaPA

Yeah, too lean for starters. Wonder if underfired.

Steamhead

m1tchsc0tt0 said:

yeah attached.

EBEBRATT-Ed said:

@m1tchsc0tt0

Your burner is not set up properly. Your Co2 reading is too high the burner is not adjusted properly and needs more air. You need a new service tech as the problem is as clear as a bell.

Co2 should be 11-12%

STEVEusaPA said:

Yeah, too lean for starters. Wonder if underfired.

This. Have them come back and do it right. On their dime.

m1tchsc0tt0

Thanks for the input everyone! According to the manual I found online it looks like CO2 should be between 12.5 and 13.5 depending on the burner disk setup does that sound right or are those maximums? Sheet attached. Also the company has already been out 3 times for "adjustments" so I am wondering if I should just call out another company and see if they do any better.

MaxMercy

Isn't 14.5 CO2 a bit on the rich side, not the lean side?

EBEBRATT-Ed

@MaxMercy Yes

Higher Co2 is rich lower is lean.

@m1tchsc0tt0

The "factory set up" is a perfect set up done in a test lab. In the field you have to work with what you have.

On a daily basis fuel quality and temperature changes,

draft changes with outside air temperature.

Combustion air temperature changes between summer and winter.

The burner air opening and blower wheel can attract dryer lint, cat hair, dog hair etc.

There are a lot of things that can change combustion

What a good technician does is adjust the burner so it will remain in a "safe range"

Your technician does not understand this.

He walked out of there with a bad combustion test, Your Co2 is too high which is causing your smoke/soot problem.


Your not going to hit the factory perfect #s all the time. You do the best you can and leave the burner in a safe operating range with no smoke

STEVEusaPA

MaxMercy said:

Isn't 14.5 CO2 a bit on the rich side, not the lean side?

I meant lean on excess/combustion air.

426hemi

I wouldn’t trust anyone who would install that with the burner up against the wall like that. I highly doubt it’s a negative pressure issue but that’s easy to tell is the soot coming from the burner air intake? Normally a negative pressure issue sucks the fire out the intake and burns up the cad cell ect I see it a lot in body shops with exhaust fans and on boats when there under way with the engine room blowers not running or they have the blowers sucking rather then blowing air in 

SlamDunk

Make sure furnace is cleaned. My guess is, it is filled with soot. I had the exact same issue with an improperly tuned beckett. I had two buckets of soot.

BDR529

Makes my back hurt just looking at it. Barometric butted up... nevermind.

I can't find the test hole. Ahh, must be on the other side of the flue pipe.
Surely that made sense to the installer(s)

Preiss

I agree with EBEBRATT-ED, setup not done well. Too rich on fuel, not enough air. I don’t see any draft or smoke on the tag. It seems to me the vent temp is a little low and the CO is a little high meaning incomplete burn. Unless there is another reason, the overall furnace/burner position makes servicing difficult which might make a less than patient tech do a poor setup. Just my thoughts. 

EdTheHeaterMan

You will want the original installer to come back and vacuum-clean and brush the heat exchanger (HX). It most likely has about 1/8" to 1/16" of soot (carbon) build-up on the inside surfaces of the HX. I was taught that 1/8" of soot was equal to 1" of fiberglass insulation. If this installing company can't get the service completed because they installed it in a way that makes it difficult or impossible to service, you want to know that now within the first year, while still under warranty.

You might want to get a web camera to record the service they do. If it is impossible to complete the maintenance properly, as a result of their installation, tell them you want it corrected. If you read the installation manual before they show up for the maintenance, you will know what to expect. You don't want to live with an appliance that can not be properly serviced.

Also, look at the "Minimum Clearance" for Service in the manual. it is usually in the first section of the installation manual. "Locating the Furnace"

If the oil burner is stuck up against a wall, and you can't remove it in 10+ years when the combustion chamber needs to be replaced, you may need to pay big bucks for relocating the furnace to get an otherwise easy repair completed.


Finally, there is insufficient combustion air. That is in the adjustment on the burner. The CO2 needs to be lower. I was never comfortable with 13.0% or higher CO2 settings. Too many times I would get the burner set up for peak efficiency on a maintenance or new install only to return a year later to a sooty boiler or furnace. 12.5% CO2 was my maximum for anything. This leaves plenty of excess air for a year's worth of build-up on the combustion air intake/burner fan/air handling parts of an oil burner.

If there is soot on the heat exchanger... that insulates the heat transfer from the flame to the warm air in the home... that can be worse than a 3% of lost combustion efficiency from too much excess air at 12.5% CO2.

That is my opinion and my customers were happy with my results.

Mr.Ed

Ctoilman

CO2 number is ridiculously high!!!....no experienced burner tech would let an oil burner be setup that way.  It's running horrible and flatout wrong.  Add more combustion air and all will be well.