Any Furnace techs here? FIXED> Thanks!

[Mosh]

I have a 10 year old Trane furnace running on propane.

Last year I noticed the burners would not light from time to time, the system would shut down and restart, then I would here that Woof of the flames. It did this only after it wasnt in use for a day or so. (We burn wood, so the furnace does not run 24-7 at times)

Well this year it seems to have escalated.The usuall "woof" of the flames sometimes takes 3 cycles to fire up. Once they fire, the furnace runs normally.

The furnace kicks on, then after about 30 seconds when you should here the flames light, it does not. The furnace runs for about 45 seconds, shuts down, and then repeats the start up process. It may fire then, or sometimes, it runs through the cycle again, then the 3rd time, you hear the flames light.

I have been reading the ignitor could be the issue. So can someone help me out here?
Is there something I should look for before I condemn the igniter?
Also what should I expect to pay for a 2 wire ignitor and are they available at Lowes, or Home Depot?

[max]

Checking the ignitor is like checking a fuse. If its is bad you will find a small break in it. I had to replace mine last year for a similar problem. Its super easy to remove and check. Any qs call me tonite.

It was about 30 bux for mine. I had to get mine from a heating/cooling shop.

[jeswinehart]

I would suspect dirty burners Rob. You are getting thru all the cycles of vent prove switch, and ignition from time to time.
If it only runa bout 5 secounds it would be the flame sensor either has corrosion on it (clean with sand paper or a razor knife).
The flame sensor might very well be sensing no flame, it needs to have flame all around it.
It is normally at the oppisaye end from where your hot surface ignitor is.
It is a single wired, ceramic encased rod (bare rod where it touchs flame). If that burner is burning lazy it very well might be getting a so-so signal.
All it do it sence flame (flame rectifcation - flame conducts eletricty and in this case, senses ground from flame)
If it was anythng else in the system, you would not get to the ignitor turning on and glowing 1600 + degree.
Do not touch that ignitor, it would be akin to touching a halogen light and burn ot early and they are real fragile anyway.
I think you are just due for a good ole burner cleaning IMO

[hang&rattle]

Call local HVAC shop that is a trane dealer. If they are good ol' boys, they'll have the ignitor and give ya a good price, if not move on to the next shop. And I don't remember who, but someone is a service tech out east of the Mississippi on here. They gave information on heat pumps. I know a little, but am an installer and shop guy, but furnace's are not all that difficult, you've probably got it figured out. Just need the model # etc.. Dirtcrasher, and Thorpe was in school too. A couple others, but can't remember. ^oops, a few beat me to an answer, lol.

[jeswinehart]

Well i got more to say but i will just call you and skip all the typing,,,

[Dirtcrasher]

The thing is, if "whatever" doesn't detect a flame, it tries a few times. Then it ignites and WOOF, all the extra gas, propane being heavier than air...........

Whether the spark isn't enough or the flame sensor says "no, shut down" it's something on that line. You gotta follow the diagram and force it and see what happens. I have seen clogged mains and burners before like John said. When it works the exhaust switch closes and it runs, if it doesn't close - shut down mode.

Don't let the transformer and all the other crap bother you, just do some OHMMS readings and search online; They're some awesome forced hot air problems with the remedy.

If it was zero outside, you'd have to scramble. But hopefully you can get by before it gets cold.

Don't let anyone say "thermocouple", they keep the pilot lit, thats there job.

[jeswinehart]

Well i got a recording on the business phone so (left my number if ya need to call but will add that it is also possible the vent might be slightly plugged up as well. Not being used very often, just the spring/fall and occasional January thaw, when it is too warm to build a wood fire,,,
If burner cleaning don't get the results needed, check out the venting for some what of a obstructing. The vent proving switch might just be on the verge of opening, or barely opening.

[Thorpe]

I would suspect dirty burners Rob. You are getting thru all the cycles of vent prove switch, and ignition from time to time.
If it only runa bout 5 secounds it would be the flame sensor either has corrosion on it (clean with sand paper or a razor knife).
The flame sensor might very well be sensing no flame, it needs to have flame all around it.
It is normally at the oppisaye end from where your hot surface ignitor is.
It is a single wired, ceramic encased rod (bare rod where it touchs flame). If that burner is burning lazy it very well might be getting a so-so signal.
All it do it sence flame (flame rectifcation - flame conducts eletricty and in this case, senses ground from flame)
If it was anythng else in the system, you would not get to the ignitor turning on and glowing 1600 + degree.
Do not touch that ignitor, it would be akin to touching a halogen light and burn ot early and they are real fragile anyway.
I think you are just due for a good ole burner cleaning IMO

I have to agree with John here... This is where I would start my electrical probing.... Any changes to your regulator pressure? Was this furnace a NG furnace converted to a LP?

[scooterroo]

more then likely a dirty flame sensor, remove it, clean it with sand paper, put it back in. then if that dont work, check the ignitor. if theres no glow, then take that out and check for a smaller then hairline crack, usually can be seen with a white haze where the crack is.

[Mosh]

All very good suggestions.

The problem escalated even more. One morning it would not fire and just ran the blower on cold air for about an hour.
I checked the code on the light and it flashed a (2) excessive lockout time for burner.
So I called a friend that used to work HVAC. Good guy.

In the end, Jeswinehart called the issue.
The flat portions of the burners were rusted shut, and not letting the flames travel across the burners to light.
Also the flame sensor was dirty. There was water trapped in the exhaust blower, and the drain collector needed cleaned out also.
He says my pump is a little lazy, but should be ok. It does not spike to 10oz like it should, but it will last awhile he said.
He cleaned it all up and did the job for $50 OTD. (Totally fair IMO.. A guys knowledge is worth alot)
This summer, I will buy new SS burners and the igniter and flame sensor. They need replaced before next season.

Thanks for the help guys, figured you would want to know the conclusion. He let me watch so next time, I can do these things myself.

[scottyms]

let me know if you need me to get you parts mr. mosh....

I own a heating and cooling company and we are a Trane dealer, you will need:

SEN01114 flame sensor
IGN00054 ignitor, this is the most common ignitor
BRN01077 stainless burners, smile these are made right here in North Ridgeville ohio by Becekett Gas

i have these in stock all the time...

it is really common for the burners to rust the "wings" on the burners shut when your on propane, so much so that the popane conversion kits now come with stainless burners...

i'm a bit confused about what you mean by your pump??? there's no pump on these furnaces... i'm thinking he's talking gas preasure? if thats the case you will need to call your propane suplier to have the check or adjust the regulator, your in coming preasure should be 10.5"wc...

scotty

ps. i've got a few seats i need recovered....

[Mosh]

Thanks Scotty. I will keep that in mind. They did not use the SS burners when the propane conversion was done.
This furnace has been less than desirable for me and the company that installed it really shanked us.
The installation company threw parts at it when it was only 1.5 years old. A Circuit board it didn't need, all because the igniter blew out.
It is a 90% eff, and I learned the warranty was 5 years. I even argued this with them and they told me to get bent.
The board should have been warranty, I came to find out, but instead they charged me 475$ for a circuit board that I did not need a year and a half after they installed the new furnace.
They actually left that OE board in the basement, and another guy plugged it in and said it was fine.I still have it to this day 10 years later for a spare.


Yeah that pump is that main control unit right off the Propane feed line then runs up to the burners. Forgive my terminology.
It hits that appropriate number on the front side, but doesn't peg the needle to 10.5 quickly on the burner side of that "injector" ???
At first it took about 1.5 seconds for it to reach the number, then it started rising faster after a few cycles.
But it fired off everytime after he cleaned all that stuff.

[jeswinehart]

What ya think Scott, low pressure cut out switch ?

[scottyms]

Back then they didnt specify to change out the burners when converting them... i would guess a few dealers in that area that are less than reputable that would have treated you in that fashion... Trane changed there parts warranty back in '99 or 2000 from a 1 year to a 5 year and today some models have a 10 year parts warranty, there was a lot of confusion as to what the lenght of warranty was back then, they picked a certain serial # and that was the switch... I'm guessing you have a TUC model furnace, honestly there a good furnace if installed and initialy set up properly. the big problems we see with poor installs usualy relate to exhaust vent lengths and improper gas preasure...

sounds like you have a regulator that needs to be looked at. we get a couple calls every year that end up being a bad or frozen regulator. i would call you propaine suplier they should send someone out to check it for no charge... once you know you have the proper line preasure then the gas valve in the furnace will need to be checked and adjusted as well...

there are a lot of good dealers out there, unfortunatle the few that do really bad work hurt us all....

to give you a little background, my father started our business in 1974... as a Tappan dealer, then we became General Electric dealers, then Trane dealers, funny thing about that those companys are all the same... they were owned by American Standard & Radiator and as they bought up other manufactures they sold equipment under the newest name.... now Trane is owned by Ingersol Rand and the product quality is better than ever.

sorry i didn't catch this thread earlier i could have told you what was going on in a about 30 seconds....
let me know if you need help down the road...

Scotty

[scottyms]

What ya think Scott, low pressure cut out switch ?

Na these furnaces are really simple, inducer comes on creates a negative air preasure in the heat exchanger thats read by the preasure switch then it starts the ignition sequence... ignitor warm up, gas valve opens burners light, flame sensor senses a flame and it opperates untill thermostat is satisfied.... with these furnaces it can usualy be traced back to lack of being serviced, dirty burners will preven the flame from traviling from burner to burner hence the flame sensor doesnt sense flame and it shuts it down, or the flame sensor is dirty and even tho theres flame it doesnt sense it... i think he needs burners and proper gas preasure more that anything else...

oh and for anyone else following this, #1 go change your air filter, #2 if your furnace hasn't been cleaned or serviced in the last 2 years make an appointment with a good service company.... for those of you that pull out the flame sensor and sandpaper it clean, your doing damage to it... there all coated, think like chrome, most with nickrathol, it helps in the flame proving with is called DC flame rectification, thats a good read on how that little bit of magic works... anyway clean them with steel wool or a stainless steel brush. and clean the burner face thats by the sensor if the sensor or burner are dirty or rusty it acts like insulation on a wire as the flame is used an electrical conductor to complete an electrical circut...

scotty

[scottyms]

Mosh, just out of curiosity who is your propane suplier? also after rereading your post about the preasures on the burner side being slow to get up to preasure you may need a gas valve as well... i've got a couple seats i will need to have recovered come spring time, maybe we can work something out and get you back in to safe and reliable heat...

scotty