Furnace not heating: useful clues before a service call

Yeah, that's a fire just waiting to happen. Uh yeah. Okay, we talked about dirty blower motors. Okay, that's a reason not to have a dirty blower motor right there is that uh a lot of times whenever especially if it gets dirty and I couldn't really tell where the sparking was originating from, but you know, anytime you do that and you've got corrosion on a blower motor and then maybe the wheel gets out of balance and then you've got, you know, electricity arcing between either electrical components or metal, that is just prime territory for a fire. And so, no one needs a fire. No one wants a fire. So again, I'm going back to what I said before, maintenance. Make sure you're getting maintenance and make sure that blower motor's clean because you do not want to fire. All right. [music and singing]

typical price on these usually run anywhere from $800 and up next part we got is a control board uh pretty much the brains of the operations everything is controlled through here your inducer your limits everything comes through here and this is what's going to tell the unit what it wants to do your your 24 volts from your thermostat is going to come here and say hey let's bring on the heat hey let's bring on the cooling so very important piece to your unit uh really love the these boards uh takes so much out of what used to be in a unit and not only makes the unit more efficient it's going to make it more safe cuz with all those limits and stuff we have on these and safety switches all that comes right into this board and can be controlled they are kind of pricey but like I said we don't see them go out that much uh typical one will last about 15 years uh taken care of you know we could even go longer this one obviously looks like it's been there since '98 that's that's pretty good Testament of how well this board was built and that we are taken care of

Okay, now we're looking at fire in a furnace. Those are the ignite the ignition. Oh my gosh, that that looks like a jet plane trying to take off. That's way too much flame. You've got gas and flames. Those are not a good combination outside of a contained space. [laughter] If you've got flames that are that prevalent that a flame sensor should be able to sense that there's something not right with the heat exchanger with the ignition, it there should be some sort of uh stop gap there. Probably due to either a lack of maintenance or um the system's really old, had been maintenance in a long time, no one's caught it. Unless you're sitting there looking at it, you just don't know that it's happening. So that's why it's so important to get eyes on this equipment regularly. [singing]

this is a roll out sensor we use this in line with the high limit switches to indicate if there's a flame roll out it's another safety kind of has the same premise of a high limit uses a little pan plate usually if you're having this go out we want to make sure we have it inspected by a professional to make sure that there's no other issues price on these can be anywhere from about $250 and that's what I tell people about this part

you're going to look at about $191 uh could be a little bit more depending on manufacturer but that's pretty good solid price we got the lovely door switch oh that door switch you know where every single technician wants to just bypass it we see a lot of them like I said that are bypassed but they're actually a safety switch why we want that door switch is to actually make sure that whoever's getting into that unit is not going to be able to mess with high voltage and all that kind of stuff you want to make sure home motor gets in there that they're going to be safe so I'm a big proponent of actually having that door switch work so anytime one goes out we really need to replace it because it is a safety feature and we don't want anybody getting into that unit that's not professionally trained on how to work on high voltage so when you're replacing that you're going to look at about $191 usually they're going to last at least 5 years I don't see too many going out in but once you get past in you might have a little bit of wear uh but typically these can last the life of the unit

this is an inducer these are used to pull flue gases through your heat exchanger the typical failure on these is actually your motor it can fail like any other motor from being locked up or having a windings go out typical age expectancy on these is about 10 years normal price on replacing them is anywhere from 550 and up that's what I tell people about this part

this is a control board very very crucial part of your system all your safeties and all your fan relays and all all all the special stuff that makes that system work is all controlled by this so if if this loses power or it's not sending out signal this is a common area to find a problem um just cuz you have so much going into it now these are a lot better than what they were they do go out so all kinds of little electronic failures usually if you're going to find electronical failure on this it's probably due to your electricity coming in the house now the typical price on replacing one of these can vary very much nowadays because of Manufacturers and different things like this is a two- stage typically going to cost around $650 and up to replace this board and that's what I tell people about this part

this is a gas valve all furnaces will have some form of gas valve this one is actually a two-stage gas valve which means it can use a high and a low gas pressure so that we're actually being more efficient typical things we see wrong with these is you have actual solenoid here that can go out that's pretty common something can get in here but that's not very common when we need to replace these the price for that can be around $650 and up and that's what I tell people about this part

This is a blower motor. You'll find this on all your heating and air units. Different kinds. Nowadays, they come more like this. These are what we call an ECM motor. They're a little bit more efficient. And so, energy standards says that all new units have to start having this. They can last a long time if you make sure that you have like your static pressure correct and stuff like that. Like any other motor, they're going to have windings go out. A lot of things that we find is this actually has a module on it. And there's different parts of that module that do go out. You can just replace the module, but really at that point, you almost want to just replace the whole thing cuz an older motor with a new module, how long is that motor going to last? So, to replace one of these, we usually look at pricing is going to be anywhere from about $1,000 and up. And that's what I tell people about this part.

it's heavily debated in our Circles of cleaning versus replacing you know a flame sensor I mean I I I want to clean them and that's that's a good part of Maintenance but there there does come a time when it replacement is imminent with with a flame sensor CU a lot of times they'll get they'll get green and kind of calcifi are wrong where but they'll get green and discolored and then even with the with the yearly cleaning I mean if you clean this flame sensor for five or six years you are doing a favor by getting the so and everything off of there but at the same time you are breaking down the the uh Integrity of that flame sensor just a little bit at a time that's one of the lowest priced repairs that you can do and that's going to that's going to save a lot of trouble calls about how much does it cost to replace a flame sensor um I believe we're at about 270 right now that's part part labor installed out the door

This is a pressure switch. This is a simple safety device just to indicate that we have our inducer running for safety reasons. Typically, these can last anywhere from 5 to 10 years. Typical price on these is anywhere from $250 to $300. And that's what I tell people about this part.

this is an inducer motor this is a crucial part of any furnace to get it the efficiency that we need a lot of furnaces were direct draft back in the day and they found just by adding a simple motor we could actually push that flu gas and make it a lot more efficient these are typically pretty good units they last quite a bit of time but they will Motors wear out typical price on this can be anywhere from $800 and up and that's what I tell people about this part

Biggest problem we ever have on these is just like the igniter, they are in horrible conditions. High high temp. It's not a total burn whenever you're burning those. You do have some impurities that can build up on this and you'll have what just different kind of impurities, soot, all that kind of stuff can build up on these and get them dirty and then they don't work. [Music]

if it's under firing the the actual heat exchanger can get a lot of soot build up in it and then the furnace will stop working and if it's overfiring you're a using too much gas and then unnecessary wear on the heat exchanger itself then that can eventually cause a stress crack

you're going to be looking at anywhere from about $750 and up these come in all kinds of different uh Motors and different types obviously this one is actually for an 80% furnace which uh is the efficiency of that actual furnace more standard now they're going to more 90% And up furnaces uh which is a little bit different but they will still have pretty much the same kind of inducers just a little bit more powerful different things like that this one actually is what we call call the Shaded pole motor that's just the type of motor uh pretty effective little motor they do go out bearings like to go out on that that's the most common problem you'll have with them they're not very efficient that's uh one reason why they're moving more towards PSC Motors and uh even variable speed motors especially with your two stage and stuff like that but overall to change out an inducer on pricing you're going to be looking at anywhere from about $750 and up it's all going to kind of depend on what it takes to replace this cuz this is one part where pretty much going to have to go back with the OEM so that kind of dictates on how expensive it's going to be

this is a gas valve we use this just for simply opening and closing your gas when you're calling for heat typical problems we find on these is they fell in the closed position and so with that is actually a safety mechanism so that we're not sending gas to your unit these usually last anywhere from about five to ten years typical cost for replacement on these is usually anywhere from 600 and up depending on the brand of gas valve that's what I tell people about this part

the main thing I'm waiting for right now is the flame to go across here that way I can read our micro amps once we read our micro amps I'll get the flame sensor plugged back in and actually check the amps on the igniter and check the amps on the inducer we're reading 3.2 microamps on our flame sensor they're rated anywhere from .5 to 10 most of the time they just need a decent cleaning and they're good to go

This is a limit switch. This is just used for in one of our many safeties that are on these units. It's just a simple switch to open and close based on what the temperature is in the unit. So, if we get high temperatures, this will shut off. Typically, these last anywhere from 5 to 10 years. They can last less depending on what kind of heat we're getting to the system. Normally, these fail due to excessive heat. And with that heat, it will actually damage the inside of these, so they'll stop working after time. And these usually cost anywhere from $175 and up. And that's what I tell people about this part.

this is a high limit switch and this is a high limit switch this unit actually comes with two high limit switches kind of shows you the safety for these units being a down flow they want to make sure there's enough air going across that heat exchanger that we don't cause any catastrophic failures to that heat exchanger so they kill the unit with these just in case that they get too high of temperature these can go out they're pretty simple little switches pulling this one out I actually broke it you have a little switch in there and all it is is a little thermal plate on there that pushes that open and close usually when you see one going out you might have another problems you want to make sure you always check it by a professional price on these can be anywhere from $250 to $300 depending on the manufacturer and that's what I tell people about this part or this part or this part

maintenance wise whenever we go out to do our heat checks the most common thing that we usually ask is is there any cold rooms any hot rooms that you notice the difference in temperature across the house um when was the last time you change the filters a lot of times that's a common thing we get is dirty filters and then also we notice a lot of time blower cleanings we do a lot of blower cleanings in the winter especially whenever we do our heater checks because people don't you would never know as a homeowner whether or not this thing is clean so it's good to have someone to come out and check to make sure that there's not dust built up because um one tenth of an inch of dust will cause 20% air loss in your house it it doesn't sound like a lot of dust but the DraStic change in air flow is very severe

this is a door switch this is really just a safety switch for anybody that's going to get into this unit if it's running it will actually kill the power to everything but come to here so kill power to board Transformer we want to have that safety because there's a lot of inexperienced people that mess with these units and when they take that door off the manufacturers wants to make sure you're safe you'll see a lot of these that are taped up by guys that's pretty common not a problem if they or bypass but it is a problem if somebody gets hurt so it's a good thing to have on there typical problems we see this is just you're going to have points in there when the door is closed and they can go out so then this would need to be replaced and the typical replacement cost of this is around 150 bucks and that's what I tell people about this part

I would say the biggest problems that we have with these have to do with maintenance, maintenance, maintenance, maintenance. Seems like we're always pushing maintenance, but it's true. I have had units where unit won't run. It's going off, you know, it's hitting my high limit and stuff like that. And then you pull the blower and this this secondary heat exchanger sits right above or below the blower, whichever. So, that blower is blowing right here. And before it goes in the coil, it goes into this light coil. So this coil right here, secondary heat exchanger, can get dirt built up on it. [Music]

the only thing of note on this is that there's dust on the blower wheel and I mean even a tenth of an inch of dust on your blower wheel can cut your air flow by 20% so it's something that we do want to recommend to the customer to pull that blower assembly and get it cleaned to make sure she has the best air flow possible in her house

moving on to the flame sensor little bit of debris this thing I I would be willing to bet this has been replaced at some point because for a 10-year-old flame sensor that is in very good shape this is what I like to clean with this flame sensor is going to be a flame rectifier so as the Flames sit on this flame sensor after a few seconds of this sensor detecting that we have a flame it's going to send a signal to the board to go ahead and bring on the blower motor so we can continue the sequence of operation for gas heat h

the heat pump was running just fine but the furnace wasn't kicking on so there's no gas it's very cold in the house when the temperatures drop real far the heat pump struggles to work which is why you have to have backup heat and so what I found was it was not igniting so I had voltage going to my igniter but it was not glowing and it was not coming on an igniter is one of the cheapest fixes that you can make on a furnace igniter is typically $250 some customers don't mind spending that and they just want to keep putting Band-Aids on on it and kick it down the road as far as they can which is fine you know this is as cheap as it gets there's not really any cheaper repair that would need to be made other than this igniter

this is a burner this is actual part where when gas goes in here it helps mix it with air to actually cause your flame to come out these usually don't have any problem with them uh what we can see is they get kind of dirty on them and so they periodically will need to be clean we usually do that with the maintenance if we see that it's an issue it does cost if you want to do that about $200 to do that maintenance if you are not doing one of our maintenance agreements when you do need to replace these I typically would suggest that you're looking at more of having other issues so you might want replace your unit but if you were going to just replace these we'd have to actually price it out and that's what I tell people about this part

if I was going to pick the one thing that's probably going to break on your unit during the winter time this would be it they're very simple devices they're literally just a metal rod with bit of porcelain here to keep it from grounding out simplest device ever is Flames go over that and the ions from the Flames can allow a little bit of electricity through to where you get a DC signal and that's how that board knows hey I have flame that's all this is flame sensor but it's a very crucial part so having cleaned once a year we'll keep it a lot longer but ultimately once you start getting to that point where it gets pretty dirty like this probably going to be replacing it

this is a flame sensor this is actually a safety device this is going to indicate when that gas valve comes on that we have flame if we don't have flame we don't want to keep pumping gas into that system what this does it actually takes this a AC signal and it uses ions through the flame to actually send a DC signal back to the board through the ground to say we have flame typical issues we have with this is a great example is you have a lot of charring up on it and we can clean those but one like this that's getting this way I would actually suggest replacing the uh price for replacement is around $120 and that's what I tell people about this part

price on this is going to be anywhere from $289 uh this is actually a hot surface igniter typically has about 120 volts come in and this will glow red get hot and then the gas will go across there and actually ignite the flame and that's how we start so this is usually only on for a oh 15 seconds roughly a common part to replace with the abuse that this gets going to last anywhere from about 5 to 15 years it's pretty weak so you got to be careful when you're handling these you definitely don't want to touch it with your bare fingers but you can see they're very brittle

ears is breaking down and like you said that's due to extended run times on them. They're working harder. When you work harder you break down faster. >> Um and it is what it is. And now you know a lot of the stuff is it's [music] not necessarily major things but it's some of the smaller things that are breaking down. >> Um you know we we've seen you know flame sensors, igniters, even even motors like your your draft inducer motor. That kind of stuff is is is really what we're seeing the most of as far as breakdowns go. Close. [singing] [music]

this is a rollout sensor the primary function of this is for safety if this ever goes off it usually means that the flame has rolled out of the heat exchanger typically these can last anywhere from a few years to the life of the unit typical replacement costs for this is usually anywhere from 175 to 250 dollars and that's what I tell people about this part

Now, what I'm going to do, I'm going to get my temperature probes here. I got one for your return and one for your supply. I'm going to drill a hole inside the plenum of the duct work and not cause any harm to the system. This is so I can get it more accurate on my wet bulb, my temperature, and what I should be reading.

okay so what we got going on here is is that this uh fan limit switch here is actually getting too close to the heat exchanger and it's causing it to twist and shut the furnace off acting like it's overheating so someone did not put enough screws in here to hold that flat against the heat exchanger and when you do the fan cycling switch cools down very rapidly and runs where it needs to be but whenever it goes like that when the see it's starting to heat back up cuz it's too close to the heat exchanger go like that it's in the airst Stream and it's properly placed just going to get a screw throw it in there and we'll be done [Music]

all right so upon putting this blower back together we had previously already pulled out one piece of folded metal thought we were all clear went to test the blower quickly and I was a little suspicious so I kept my hand right next to the pigtail to unplug it and sure enough about a second of run time I hear a big thud Tink sound and another piece of metal had fallen out from the heat exchanger so now I really need to dive in deep and figure out why somebody had been wedging these pieces of metal in the heat exchanger if we were to all Ely find out that this furnace is not under warranty I would recommend getting an estimator out here because we have a lot going on and I'm concerned about the overall safety of this especially if somebody's just shoved metal in there to to combat issues the longer we work on this particular call I'm starting to wonder what all kind of Corners might have been cut and what kind of a quick quick fixes that weren't the best fixes might have been done

this is a pressure switch this is a very crucial part of a system it's actually just a safety switch to make sure your inducer motor is coming on this one actually here is actual a dual pressure switch cuz this is actually a two-stage furnace most time you would just have one of these pressure switches they can go out what usually happens in here has got little contacts inside and sometimes those will go out where they're not making good contact or you can get gunk built up in the lines is what we see a lot of problems so that's something you don't have to replace now when you do have to replace this the typical price for replacing this is anywhere from $200 and up and a lot more for a dual Port like this and that's what I tell people about this part

These are going to be your limits. Some of these these ones right here are actually roll out limits. And you'll see they're resettable because they want if they have a roll out, they want somebody to look at it and that's the reason they do that. This is actually a high limit and this limit resets. So if your heat gets too high, it'll kick it off, run the fan for a while, so it cools down that heat exchanger, then it'll allow you to go back to back to business once it reach its its point. When you're looking at any of these to replace, you're looking at about $293. [Music]

I'm Robert with Y brro and Suns and today we're going to be doing a maintenance on this furnace making sure everything's running properly and making sure it's safe first thing I like to do I've already got this wire disconnected I like to pull and clean the flame sensor before it ever runs that way this flame sensor is right in the path of the flame if you do it after it runs it is very very hot there's several different ways you can clean these dollar bill Emery cloth you just want to stay away from like sand cloth because it can actually damage the flame sensor itself but you just take it off clean any carbon buildup off of there that way it's able to actually sense that flame and send a signal back to the circuit board

this is a blower wheel pretty common to find on all your units they're going to be something like this what we usually find on this is these Scoops can actually get out of balance start falling apart you can kind of usually know that that's going to happen cuz you might hear kind of a like a slinky sound I always like to say it is and that's good indication that something's wrong with your blower wheel and maybe even your blower motor another thing that we see a problem with is these do need to get be cleaned periodically um they do build up dust depending on how much you change your filter so definitely always change your filter um but if they build up just even a tenth of an inch of dust you can lose up to 20% of your air capacity to clean these we look at pricing it anywhere from uh right around $250 and then to actually replace this wheel we'd actually have to call the manufacturer cuz it can vary from anywhere from $500 and up and that's what I tell people about this part

this is igniter there are many different types of igniters on systems this one actually uses a spark to start up a what we call a pilot light to actually light your flame this can usually fail for many different reasons typical price on replacing this can be anywhere from 200 and up depending on what kind of assembly you're using and that's what I tell people when they ask me about this part

typical price on this is about $312 this is a pressure switch the whole point of this is to actually take a pressure reading from the inducer to make sure that inducer is actually running a lot of these will actually from the board have a 24 volts going here all the time so it will see that the this pressure switch is what we call open so it knows that inducer is not running then it will actually kick on the inducer and then close and so it'll know the inducer wasn't running at first first now it is running so now we're safe to go ahead and move into or move on to our sequence of operation unlike that natural dra draft furnace your grandma had in her house we want to make sure you're safe

[Music] this is a control board we use this component usually for controlling our fans for controlling our inducer motor controlling our gas valve and all our safety switches and it's a crucial part of any furnace a typical life expectancy of this is about 10 years but if it breaks typical cost is usually around 500 and up depending on type of furnace and that's what I tell people when they ask me about this part

our gas pressure on this is 3.9 which is actually a little high these are rated for 3.5 and that's something we would typically fix and that's going to prevent undue wear and tear and to do that we would take a screwdriver pop this little brass plug out and then there's an adjustable set screw down in here let's adjust that out to lower that pressure and it doesn't take very much and we want that to get right around 3 and 1/2 inches water column and that's just the amount of pressure going from your inlet side of your gas valve to your outlet side