Thank godness for the internet, furnace repair.

[iheartmaytag]

The last few days was cool enough in the mornings that we needed the furnace to take the chill off.  I had been noticing that the Coleman/Evcon furnace would come on, the igniter would glow, burners would light, and immediately go out.  Usually it would finally be ok and run the second time it attempted.  

 

Well yesterday, it didn't light, and on the third attempt it locked down and wouldn't retry.  Luckily we have a gas fireplace we only had to light about 30 minutes and things were fine.

 

I was worried about having to call a repairman, especially the cost.  I either called them out on Sunday and paid overtime, or waited til the week , and would have to take off work.

 

Asking myself, what would the AW members do?  I looked up the problem and discovered it was the flame-out sensor, much like the thermocouple.  Even had a video of how to clean it and replace.  

 

This morning it took me about 10 minutes, to undo one screw, clean the sensor with a bit of Emory cloth, replace it.  Everything is working again, thank goodness.  $85 service charge avoided, and more knowledge gained.

 

One think I was glad I learned, don't actually touch the sensor with your fingers, the oil from your hands will shorten it's life.  I worry now about the igniter, the video said to always keep one on hand, as they go out without notice.  I think I will order one just as a teddy bear to have.

 

 

 

[wayupnorth]

I just had my oil boiler serviced this week and my service guy said everything is fine. But inevitably, come end of January, it starts rumbling. I keep an extra new burner nozzel I can switch out and it runs fine for the rest of the heating season. No need to pay for a service call either.

 

[lordkenmore]

Not furnace related, but I had a problem with car lock out situation--lock broken, and the alarm armed. I had arranged for someone to come out to get me in when I tried Googling one last time, and found a suggested tip. Nothing to lose, so I tried it...and low and behold, I was able to get the car unlocked and alarm shut off.

The road side assistance guy--a small one guy operation, I think--was even nice about it when I called to cancel. It's nice when someone like that is happy his services aren't required. (Then, I gather he had a busy day...and so maybe he was just happy to have one less thing to do even if meant less money!)

 

[panthera]

At our altitude,

When things go south on the heat, it leads to burst pipes.

So when a furnace fails, the chance of getting a repairman out in time is null.

I think there are more women in their '80s here who know how to fix these sorts of things than who do not.

People need to learn the basics of modern, electronically controlled furnaces. Have the silly little automotive fuses and standard fuses on hand. Know where the sensors (especially the flame sensor which does get dirty and must not be touched) are and how to fix them.

And thermocouples.

 

And, keep a few cheap electric heaters around. No, if the power goes out it won't help, yada-yada-yada. Still, nearly everything which goes wrong with a modern electronically controlled furnace can be fixed fairly easily by the home owner if they know what's up before they need to. Things like changing out the batteries in the thermostat now (and having a mechanical one in the circuit set to turn on at 55F isn't dumb, either).

 

[abcomatic]

I have a question: Flame-out sensor? Is this the round plastic sensor that has one tube and a couple of wires that are attached to it? If it is, I have had problems like that too. I take it off, blow through or try to because the hole is small, reattached it, hook it back up and away she goes. I do the same think exactly. I have even gone to the furnace supply company, gotten my own and install it myself.
Go for it! Those furnace repairman are not cheap.
I hope you will let me know if we are talking about the same thing. Bye for now and happy heating. Gary

 

[iheartmaytag]

I imagine they are the same thing, I am sure that each model is a little different.

 

On my furnace it is a small porcelain obtrusion sticking up from the main burner.  It is held in place by one screw.  The metal part is about the size of a pencil led and about 3 inches long.   The one in the video has a 90 degree bend, mine was straight.

furnace flame out sensor - Search Videos

www.bing.com

 

[gusherb]

Steve Lav fixes a couple of common issues with furnaces in this video of an American Standard 95% furnace (also the same thing as the Trane XV95 which is one of my furnaces).



I personally have had to clean flame sensors many times. A family friend has me service this old dinosaur 1983 Magic Chef furnace of hers with some very early electronic ignition system, it's always the flame sensor not proving because the pilot gets dirty. Some furnaces actually used the hot surface ignitor as a flame sensor, I've never worked on one like that. But I do agree that you should keep a spare HSI around as those are probably the most fail prone part in a modern furnace and will fail with zero notice. A flame sensor can easily be cleaned.

 

[cuffs054]

Same here. Flame sensor on my Amana gas pack does the same thing.

 

[beekeyknee]

And those inducer fans. What a pain. Always going bad. Have to watch them like a hawk to make sure they're oiled properly. And even then the bushing closest to the combustion chamber gets exposed to humidity and goes bad sometimes. How did we ever live w/o those things. Now they're on water heaters. Ugh. Rant over.

 

[volvoguy87]

Parts

Having a spare igniter is a very goo idea. Cleaning a flame sensor will get things working again, but you're often on borrowed time. It's a good idea to have a spare one of those too. Fortunately, they're cheap.

It's a good idea to check on the rubber vacuum lines as well. The acidic condensate from those high-efficiency condensing burners can damage this tubing, and when it is no longer vacuum tight, the pressure switches won't be activated and the draft inducer and burner will shut down.

They also fail most often at the most inconvenient times.

Dave

 

[panthera]

Vacuum lines

No kidding. A client couldn't get a repairman out, it was -20 (no need for C or F on that one!) and things were getting serious, fast.

We tried everything then she remembered the last furnace guy had blown cigarette smoke against the vacuum lines (this is Wyoming, remember - gas and glowing embers, what could possibly by bad about that?).

She thought he was dunderheaded, but there'd been a leak. Sure enough. We trimmed about a centimeter off of every rubber line, stuck it back on with rubber cement (we'd turned the power off first, not quite as D-U-M dumb as the repairman) and waited five minutes.

 

Sprang to life and stayed on until she could get a repairman up TWO WEEKS later.

I suspect those lines are meant to be a weak point, designed to fail.

 

[kb0nes]

I'm not convinced that touching the flame sensor probe will cause any harm, it is simply a wire that sticks into the flame. It is made of a non-corrosive metal so I can't imagine finger oils will do it any harm. Probably best not to smear peanut butter on it though...

The flame sensor function is kind of amazing. There is actually a small electrical current that flows through the flame from the burner to the sensor probe to allow the control to know the flame is present! It is a very high impedance (low current) circuit so things must be clean and tight and well insulated.

I had one furnace I worked on that would have several ignition cycles before the flame would finally hold. On this furnace the flame would kind of "bounce" when the gas valve popped open. The flame would step away from the burner briefly a couple times during the bounces and the flame sensor senses the lack of flame and shut down the gas valve. I swapped a capacitor on the control board to extend the time delay by a few hundred milliseconds so it would ignore the bouncing. It would still shut down in about 1/2 second with a full flame out though. Having 3 or 4 ignition cycles to get a successful ignition every time the thermostat called for heat sure ate up the igniters. A spare igniter should be kept handy.

 

[iheartmaytag]

Don't touch

Was only the instructions given, and the reason being it would reduce the life of the component.  Just relaying what it said.  I would assume besides the oils in our skin the salt is also corrosive. 

 

On the Coleman/Evcon unit it tries three times then locks out.  You have to reset the power to get it to try again. 

 

[gusherb]

What shouldn't be touched

Is a hot surface ignitor. Those are brittle and will break very easily. I think the oil off ones skin will do something to them too. I've touched plenty of flame sensors and didn't have an issue after.

 

[iheartmaytag]

I dunno

I was told not to touch it, I didn't touch it.  Next time, I don't plan to touch it either. 

[this post was last edited: 11/15/2016-12:18]