Furnace help

[Czar]

I called the furnace company because it wasn't working on morning. They came by and said it was th blower motor, but because the filter was dirty it would not be covered under warranty. It was cold, so I told them to replace it.

The next morning, it stopped working again (same error code). They came in and replaced a bunch of stuff and then it started overheating and shutting down. They came back and replaced a sensor and it's still not working. Now though, it's failing to ignite, and locks out after 3 tries.

They are now not going to come back until I get the furnace cleaned (they think it's overheating because it's dirty), which means I need to reset the furnace every couple of hours to keep it going (the gas fails to ignite every once and awhile and locks outf for an hour).

So, here are my symptoms:

- igniter glows, but sometimes it doesn't light
- I smell gas in my house. I'm guessing it's because the gas valve opens, but doesn't ignite.
- I'm guessing it the igniter (not hot enough) or the control board (not enough current to drive the igniter)
- I haven't seen it overheat. Are at the vents are approx. 50 degrees above outside temp.

Also, I've testing the windings on the old motor (it was only 1 year old), and they seem good (no shorts to ground, and no opens across all windings). Should I complain about this? They are threatening to cancel my warranty though.

[Env-Consultant]

Not too helpful, but how dirty was your filter? If it wasn't absolutely thick/disgusting, it should 100% be covered under warranty. I replace mine frequently and never let it get too bad, but still. How old is the furnace?

Sounds like you might have some guys on your hands that really don't know what they're doing - you don't just replace shit, at someone else's expense, until it works. They should be able to properly diagnose the problem and repair it properly. How strong is the gas smell? Might be best to crank it off - shouldn't be a problem, but it sounds like your furnace has a mind of its own. CO detectors do not detect NG.

I would call them and explain everything written above, ensure they will make it right, and let them know you will be posting their company information along with the details of your experience and their subsequent response on a major YYC forum + several review websites. Completely legal and you wouldn't believe how well that technique has worked for me in the past. It doesn't hurt to mention that you are a partner in an internet marketing and SEO company - I'm not... but them believing I am tends to increase the responsibility level tenfold.

[Maxt]

What brand of furnace is this?
And it's a dick move to deny warranty, especially since the parts are covered by the manufacturer, and how "dirty" was the filter? Customer usually ends up paying labor for warranty work or a part of it, because the manufacturers are so cheap with the labor times, ie: it takes around 3 hours to get to your house, diagnose, pickup motor, return and install, but the manufacturer will only pay 1 hour for that work.
The ignitor may work but sometimes they don't get hot enough to ignite the gas, could be a gas pressure problem, or even a cracked exchanger causing issues with the draft through the exchanger.

[Czar]

Apparently what happened was that they found a second filter in the slot. The slot they made to hold the filter has barely enough room to hold a filter and sometimes it actually rips the paper. The guy actually charged me an extra $100 to replace the blower because he had to "clean" the burners since it only intermittently started.

I came down one time and the filter was "missing" so I put another one in. I guess there was another one in there (although it wasn't really close to the blower or anything. I have to admit though, I hadnt replaced it since the beginning of summer so it was dirty, but no so much that it restricted the flow. Without the filter the furnace will litterally blow off the registers. (I had a company come in to tape and seal all the ducts because I wasnt getting any air to my furthest rooms).

The furnace is a Coleman. They seem to come in every year or so since I've had it (coming up 5 years) and replace stuff because it stops running. So far they've replaced:

- Blower (2x -- once on warranty and once I paid)
- Burners
- Gas Valve
- Temp Sensor (from the zone controller)
- Inducer motor


Weird thing is that if I reset the furnace it will start back up, but it never seems to work after the initial heating cycle.

I'm kinda most upset at being charged to replace the blower even though (I think) the old blower is fine. Is there any place I can take it to get verified? Like I said, I checked the windings (resistance) and it looks fine.

[Seth1968]

With the gas smell, don't even attempt to run the furnace.

Have you, or the furnace guys addressed the error code?

[Maxt]

What model is it? Check the codes through the window. Codes are on the back of the cover. Variable speed or multi speed motor? Coleman is a york furnace fyi.

[Czar]

Error Code 7: Flame could not be established.

The gas is probably from when it can't light. It's not too strong, so I'm not too worried.

It's a TG9S.

I'm going to try and run it with the door off. I wonder if it's an issue with not enough outside air.. It failed to light with the door on, but light once I took the door off..


The service company seems to think that it's because of an overheat condition, but I doubt that since I've watched it not light the burners.

[Maxt]

Air supply problems usually show up as an air switch code,but sometimes bad piping affects the ignition as well. The ignitor is the place to start if it's getting gas and won't light. failing that you will need someone with a manometer and combustion tester and the skills to use them to troubleshoot it further.

[Waldi]

I had a Colman furnace in the previous house and found over the years one in a while got problem with flame sensor or ignitor (furnace running but no flame so blowing cold air 90% of time). Flame sensor would have deposits due to the fact that it is in the middle of flame so once a year I did clean it with fine sandpaper (gently) and wet cloth. This resolve all the issues, I aslo got replacemnt flame sensoe (~$25.00) and kept it in the furnace room just incase as it take about 2 minutes to switch. Also their ingitor is very brittle and should be gently cleaned. I was not so gentle so had to get one and re-install (pretty simple task as well). Parts are hard to come by, I found Coleman parts place in NW and they do carry or can order parts. Hope that helps.

[carson blocks]

I agree that it sounds like it could be a simple flame sensor issue. Very easy to clean, just turn the power off to your furnace, remove it, clean it with a scotchbrite, and reinstall. My HVAC guy told me to do mine once a year.

[Czar]

I cleaned the flame sensor a couple of times already, so I don't think that's the problem (although I'm not sure).

Now that I've had the door off (of the burner area) for over a day, all seems to be working. No errors and I'm getting heat consistently.

I checked the intake, and there's no visible sign of something blocking it.

So, in summary:

- Door off : works
- Door on : Error code 7


(This is the door to the burners so there is no switch on it)

Hopefully the furnace company comes out in the next couple of days to troubleshoot (again)..

[ZenOps]

Sounds like maybe not enough air intake.

Don't use the expensive pollen filters, try using the cheapy 99 cent fiberglass ones and see if it helps. The expensive filters can choke off too much air.

As a general rule of thumb, use pollen filter only in summertime when the burners will not be on and you want to circulate fresh air through the house.

[rx7_turbo2]

Originally posted by ZenOps
Sounds like maybe not enough air intake.

Don't use the expensive pollen filters, try using the cheapy 99 cent fiberglass ones and see if it helps. The expensive filters can choke off too much air.

As a general rule of thumb, use pollen filter only in summertime when the burners will not be on and you want to circulate fresh air through the house.

On a high efficiency furnace the filter you're describing is unrelated to the combustion air supply.

[Tik-Tok]

Originally posted by Czar

Now that I've had the door off (of the burner area) for over a day, all seems to be working. No errors and I'm getting heat consistently.

I checked the intake, and there's no visible sign of something blocking it.

So, in summary:

- Door off : works
- Door on : Error code 7

Almost sounds like there's something plugging the burner air intake. Did you look at the house exterior intake for it?

[Czar]

Yeah.. Intake is fine (I ran a snake through it and it was clear). The guy I normally use is on vacation until next week, so I'm waiting for him.

In the meantime I got a Carbon monoxide detector just in case..


FYI... The company has decided to ignore me now (since my warranty expired last Wednesday).

[rx7_turbo2]

Sorry double post.

[AndyL]

Didn't I read somewhere about frozen intakes? (In other words ice accumulation in the intake)

Carmon (403)926-3637 is my good HVAC guy...

[sillysod]

whoever worked on your furnace fucked you.

just sayin'

this city if flooded with techs that have no idea WTF they are doing and the companies don't have a lot of options so they just keep them employed.

get someone else and try to get some money back if you can.

[ZenOps]

I'm pretty sure if the circulating air intake is weak (because of too thick of an air filter) the exchange block itself will get too hot and trigger the overheat signal which will cut the gas. It looks the same as a flame sensor problem, but usually much deeper into the furnace cycle (Dirty flame sensor will be almost immediate, not enough circulating air will be much later, almost when its ready to normally shut off) It think there are two overheat sensors, one where it shuts of the gas and simply waits for the circulating air to catch up, and the other which is the way too damn hot sensor, which shuts the whole thing down.

If it did not have a filter at some point in time, someone else probably figured out that it was working without, and just left it off to be fixed later. Which only makes things worse in the long run, you need at least a large particulate filter at all times.

My combustion air intake has a nasty habit of picking up leaves like a vacuum, that should be checked as well. Most if not all furnaces have leaf traps for the combustion. It sometimes is right at the end of the intake inside the furnace.

[rx7_turbo2]

Originally posted by ZenOps
I'm pretty sure if the circulating air intake is weak (because of too thick of an air filter) the exchange block itself will get too hot and trigger the overheat signal which will cut the gas. It looks the same as a flame sensor problem, but usually much deeper into the furnace cycle (Dirty flame sensor will be almost immediate, not enough circulating air will be much later, almost when its ready to normally shut off) It think there are two overheat sensors, one where it shuts of the gas and simply waits for the circulating air to catch up, and the other which is the way too damn hot sensor, which shuts the whole thing down.

The OP is getting error code 7 "flame could not be established". If there was a lack of circulating airflow tripping the high limit he would receive that error code instead. After a given number of those errors the furnace would then lock itself out. In addition the "way too damn hot sensor" is known as a roll out sensor, this is a manual reset switch, once tripped the furnace is locked until operator physically resets the device, it also has a specific and unique error code which the OP is not getting.

You say "It looks the same as a flame sensor problem" this is incorrect. The issues you described have separate and unique error codes the OP is not witnessing.

The fact the unit operates correctly when the door is off suggests highly the issue is with a lack of combustion air, which is again totally separate from circulating air. Because of this your comment about leaves is appropriate, there is usually some kind of grate, screen, etc in the intake somewhere close to the plenum, it could be blocked. I've also seen issues where a two stage gas valve stuck on high will cause ignition issues.