Frustrated and Nowhere to turn!

RodM

About 2 years ago I replaced an old (approx. 15 years) oil furnace with a new SummerAire FSSL080 Oil furnace which came with a new Beckett AFG oil burner and Honewell R7284 Primary Control.
I have had issues with it shutting down and recently I can't keep it running.
I had it professionally installed and I have had techs look at it and tried all of the usual things....changing nozzles, CAD, air mixture, etc etc etc.
On Thursday (the most recent time I had a tech on it) the tech cleaned out the whole furnace, put his analyzer on it and worked with adjusting the air concentration. A few days before he changed the nozzle and checked the CAD. He got the CO2 reading to the recommended amount but could only get the ohms down into the 2100 range.
When he left I stayed and watch the ohm reading (it is constantly displayed on the R7284 Primary Control) As the furnace kept running the ohms would gradually increase. The unit would also shut down and go to standby mode while the fan continued to run even though it had not reached the thermostat temperature. I understand that this is a safety measure that occurs when the heat in the chamber gets to high and needs to be reduced before firing starts again.
When I left the ohms were reading between 2100 and 2700.
I came back two days later and the furnace was out on Hard Lock Out. I reset it and the ignition started, called for flame and started to run...the ohm reading was between 4700 and 5100. it kept running for about 20 minutes or so then went into standby with the fan still running but it did not reach thermostat temp yet. It started the ignition cycle again and started running. It went through that cycle about 5 or 6 times with the frequency between cycles getting shorter. The ohm reading gradually increased during this time and remained in the 5100 area and greater. It finally shut down and went to Hard Lock Out. I took the CAD out and put an ohm meter on it covered the end and the ohms went way up, put a flash light in front of it and the ohms dropped to single digits. So the CAD was working properly.
I am at loss. The techs seem to be out of answers. They can get it to run but can't keep it going. We have 8 oil furnaces in various places, some have been running over 30 years, and never had any real problems except the regular maintenance issues. This new one with all the fancy electronics on it has ben giving me grief since it was installed.
Has anyone seen anything like this before or have any suggestions as to what may be wrong?
Any help would be greatly appreciated

icesailor

Does it have the proper brand, type, style and spray that is called for? Was it down rated or down fired from what was called for in the beginning? Does it have the correct pump pressure?

Did YOU or the Tech lift up the transformer and look down the tube with a flashlight to see if you can see through all the openings for air to pass through the end cone? In the hole in the middle, did he stick his finger down into that hole and check for hard carbon deposits that might be built up in front (the chamber side) of the end cone? It causes those AFG's to misbehave. It makes them get smoky and the Ohm reading will go up sometimes. If there's any there, scrape it out with an old copper fitting brush. Did they replace the oil tank? Do you have Spin-On Filters to clean the oil? With contaminated oil in an old tank, and third world filters, I have seen nozzle strainers plug up in minutes and the only way to diagnose it is to put a new strainer on an old nozzle and it runs properly. For a few minutes or hours.

If the sticker on the burner for that furnace says 1.10 60' B, make sure it is a DELAVAN 1.10 GPH 60 degree B or Blue/Solid Nozzle. If all the techs that have played with it were playing "Fun With Nozzles", put what is required by the manufacturer and start over from there. If it calls for a 1.10 GPH, you can down rate it to a 1.00 GPH, the same spec's. If they down rated it too much, be sure that you have the proper head and plate in it. That's a fine burner in a oil furnace. I'd be replacing it with a Carlin but it might burn right through it. Same with a Riello.

I'm assuming that there is sufficient draft over the fire and in the breeching. AFG's have a real allergy to poor or a lack of draft.

They can actually go in to oil burner anaphylactic shock. and croak on you.

iix

Check the drawer assembly, it could need a good cleaning, the part the holds the electrodes in place may have been over tightened blocking the cad cell's view of the flame. Sometimes a little metallic spray paint in the blast tube will lighten things up in there.

icesailor

"" Sometimes a little metallic spray paint in the blast tube will lighten things up in there. ""

Not with Ohm's readings up in those numbers.

Steamhead

Is the CAD cell properly aligned so it points to the burner head? Don't laugh- I've seen this cause very high ohm readings.

billtwocase

you are either under firing the unit, of have a fuel supply problem. Never heard of this unit. Do you have some pics? I would also like a pic of the air band/gate, nozzle size, degree angle, hollow or solid, fuel tank and lines, and his printed test results. Was this serviced recently? Internal access ports? This is a start

Robert O'Brien

Is it a two pipe oil supply? A furnace should never go off on limit,you have airflow issues although that has nothing to do with the safety issue

billtwocase

I think you have a Beckett NX on that, and not an AFG. That would explain the high OHM readings. I was checking the internet, and found some specs.That furnace has either a Riello, or NX on it. Looks like a .50 60W would be the nozzle for the Beckett

icesailor

That's one complex unit to set up. Did you see them do all the testing shown in the manual that Billtwocase posted? Is this unit direct vented or chimney vented? Is it sooted up? Does it have the correct nozzle in it?

If it ran when it was installed, it should be able to be put back properly today.

STEVEusaPA

Has anyone looked thru the error codes & diagnostics history on the primary? And the standard.....where are you located?
I also noticed in the manual posted, that the first 2 btu sizes use the same nozzle, but very different pump pressure

RodM

You are right Builtwocase, it was a NX. On Monday the tech who installed it changed the NX out and installed an AFG. After installation it was chugging and he tried air adjustments and several nozzle changes to remedy the chugging and shut down. Finally, with no other ideas to stop the chugging and shut down he tried a .80 nozzle and the unit worked. It was working yesterday but I haven't checked on it yet today.

Thank you everyone for the input

icesailor

RodM said:

You are right Builtwocase, it was a NX. On Monday the tech who installed it changed the NX out and installed an AFG. After installation it was chugging and he tried air adjustments and several nozzle changes to remedy the chugging and shut down. Finally, with no other ideas to stop the chugging and shut down he tried a .80 nozzle and the unit worked. It was working yesterday but I haven't checked on it yet today.

Thank you everyone for the input

He replaced the NX with an AFG and didn't replace it with a 80 degree nozzle? I hope that it was a Delavan nozzle.

That leads me to ask, what did he have in the NX? The majority of AFG's that I worked on that had "Issues" with, were serviced by someone that believed that a 70 degree nozzle was a "Universal" nozzle. Half way between a 60 degree and a 80 degree. And he trained a ton of people to believe that. Problems were resolved by scraping the carbon build up on the outside of the end cone, and putting the proper nozzle in it. In this case, it says right in the boiler manual. Or a OEM guide from the manufacturer.

What kills oil is the bad service. And bad service is noticed right away by things like smoke or "huffing".

You can leave gas in a really sorry state and no one knows.

Or so some of us discovered when we bought and/or started using digital combustion analyzers.