OT- Furnace question

Re: OT- Furnace question

Larry verhoff

When was the last time you had the furnace checked out, like having the ignighter cleaned. I would have a furnace man to do that. Larry

Re: OT- Furnace question

Mark Nowicki

https://www.youtube.com/c/acservicetechchannel/videos

https://www.youtube.com/watch?v=u3bxZRjXxRM&ab_channel=ACServiceTechLLC

https://www.youtube.com/watch?v=lG1sIuQUXmY&ab_channel=ACServiceTechLLC

https://www.youtube.com/watch?v=PiCmfW1rTRY&ab_channel=ACServiceTechLLC

Plus a few more.

Re: OT- Furnace question

John K Jordan

>>>So I unplugged the replugged the ignitor and it has been fine.

Caveat: I know zero about gas furnaces and have never had one.

That said, could the contacts on the igniter have been the problem? On many electrical devices simply unplugging and re-plugging can clean dirt or slight corrosion from the contacts and make them work again.

Since any type of contacts can degrade with humidity, heat, or air, I coat them with a thin smear of dielectric grease. This is available in any auto parts store and in larger quantities at electrical supply places. This prevents contamination, oxidation, and corrosion. I use this on every contact on automobiles, farm equipment, light bulb bases, and even in electrical panels. It is especially useful on lightbulbs and connectors on vehicles and equipment which spends time outdoors.

JKJ

Re: OT- Furnace question

Tom Norton

John that is what I have been wondering. I have been checking on the furnace through out the day and it is running fine!

Re: OT- Furnace question

walta

To start the furnace a series of things must happen each step has a time limit if any step fails the furnace goes back to step one after 5 or so attempts the unit will lock out until the power is reset.

The steps vary from one make and model to the next.

Most furnaces today have a flame sensor and it sounds to me like your sensor is dirty or failing.

Walta

Re: OT- Furnace question

Dave Bair

I agree that it seems like your flame sensor needs cleaning. Extract the probe and clean it with a dollar bill; resist the urge to use emery paper or any other abrasive.

Re: OT- Furnace question

Tom Norton

Thanks Dave!! Just educated myself about that component. Will give it a cleaning tomorrow!

Re: OT- Furnace question

al morgan

Also, many furnaces have a "sail" sensor that detects if the fan is running. The fan is run before the gas light off to blow out any previous false start combustible gases that may have accumulated. The sail sensors is nothing more than a "flag" or something that will be pushed by the air flow from the fan and it will pivot and close(or open) a micro contact switch thereby indicating the air is moving in the ductwork. So it could be the "sail" switch is intermittently working. Maybe the micro switch is bad or the "sail" has accumulated dust on it and is not pivoting freely.

Also, sometimes on furnaces (or manuals) there's a "ladder diagram" showing you the logic and sensors that need to activate and in what sequence before allowing the spark maker to spark. Also, will show the thermostat signal, high temp cutoffs, low temp cutoffs, etc. The furnace is actually a pretty complicated device (with safeties)...the thermostat is a bit of complicated device itself too. Fortuneately, most of the sensors are real simple and relatively cheap.

Good luck!

connections

John K Jordan

>>>John that is what I have been wondering.

Once at the Lab I walked into an area where a group of techs were trying to get a graphics computer running. (such a machine was a huge deal and incredible expense in the late '70s!) They had been working on it for hours and were exhausted. I said let me take a look - I used my thumb and pushed on every socketed chip in the machine. Some move a bit, probably loosened by the expansion/contraction cycles of heating and cooling. The machine booted and ran then!

One of the first things I do when debugging electrical things is reseat all connectors. It's a cheap thing to try and it works sometimes. I've no way to know if this was the problem or only problem with your furnace, of course.

JKJ

Re: OT- Furnace question

AZ in Colorado Springs

My gas furnace is about 19 years old. In the past two years I've had to replace (well, a technician did it) the negative pressure fan and the pressure sensor, and the guy cleans the flame detector (uses a rag with some sort of cleaning solution on it) every time he touches the furnace.