00:00:07.970 hey guys Jay here with word of advice TV 00:00:10.73000:00:10.740 so today after lunch my wife calls me up 00:00:13.03900:00:13.049 at about one o'clock and tells me I just 00:00:15.70900:00:15.719 came home and it's 61 degrees in the 00:00:17.68900:00:17.699 house I'm thinking shoot I'm only going 00:00:20.09000:00:20.100 to come home at like 6 o'clock it's 00:00:21.59000:00:21.600 gonna get even colder by then so I tell 00:00:23.68900:00:23.699 her okay just go down to the furnace and 00:00:25.49000:00:25.500 tell me what it's doing and she says 00:00:27.41000:00:27.420 there's no flames that glow thing is not 00:00:30.50000:00:30.510 glowing nothing's really working up on 00:00:32.95900:00:32.969 top but the fan is running so I tell her 00:00:35.66000:00:35.670 all right can you look in the sight 00:00:37.28000:00:37.290 glass on the bottom door and tell me if 00:00:39.20000:00:39.210 you see anything that she says yes I do 00:00:41.18000:00:41.190 see a light inside the sight glass I 00:00:43.04000:00:43.050 tell her okay that's great now if you 00:00:44.81000:00:44.820 could just count how many times as 00:00:46.16000:00:46.170 blinking and let me know and she was 00:00:48.13900:00:48.149 counting it you know one two three four 00:00:49.85000:00:49.860 pause one two three four so I was 00:00:52.79000:00:52.800 blinking four times so on my control 00:00:55.18900:00:55.199 board I have a diagnostic chart it's 00:00:56.84000:00:56.850 either gonna be on your board or in the 00:00:58.52000:00:58.530 back of your furnace door in fact let's 00:01:01.76000:01:01.770 just take them off usually on most 00:01:06.05000:01:06.060 furnaces the diagnostic chart that 00:01:07.78900:01:07.799 explains your error culture fault codes 00:01:09.95000:01:09.960 will be somewhere on the back of your 00:01:12.08000:01:12.090 furnace door and mine all I have is a 00:01:14.48000:01:14.490 schematic as you can see but on most 00:01:17.33000:01:17.340 furnaces that diagnostic chart will be 00:01:20.03000:01:20.040 on the inside of the furnace door in my 00:01:23.92900:01:23.939 case most furnaces don't have it like 00:01:25.88000:01:25.890 this but on mine my diagnostic chart is 00:01:29.24000:01:29.250 right on the control board itself and on 00:01:33.14000:01:33.150 my board it says here that four flashes 00:01:35.56900:01:35.579 means that my thermal protection device 00:01:37.88000:01:37.890 is open 00:01:42.27000:01:42.280 and just so you know I'm different 00:01:44.10000:01:44.110 furnaces that will be called different 00:01:45.63000:01:45.640 things for example your board might say 00:01:48.15000:01:48.160 or your diagnostic chart might say that 00:01:50.04000:01:50.050 your upper limit is open or you have a 00:01:52.20000:01:52.210 limit lockout or it will say high limit 00:01:54.71900:01:54.729 open something to do with the limit or 00:01:57.00000:01:57.010 in my case it said thermal device but it 00:01:59.46000:01:59.470 was talking about the high limit which 00:02:00.99000:02:01.000 is right here on most furnaces it will 00:02:04.38000:02:04.390 look like this it's a black square like 00:02:07.74000:02:07.750 that and that is your thermal device or 00:02:12.72000:02:12.730 your high limit switch so if your 00:02:14.82000:02:14.830 furnace is ever overheating this switch 00:02:17.16000:02:17.170 right here shuts down the furnace and on 00:02:19.80000:02:19.810 some furnaces instead of a rectangle 00:02:21.63000:02:21.640 like this it'll be either black or brown 00:02:23.37000:02:23.380 sometimes it'll be a bi-metal switch and 00:02:26.31000:02:26.320 it'll be just like a round little thing 00:02:28.11000:02:28.120 I'll add a picture so you can see what 00:02:29.61000:02:29.620 that looks like so it's blinking four 00:02:31.53000:02:31.540 times right which means my high limit is 00:02:33.30000:02:33.310 open and I'm thinking okay maybe if she 00:02:35.34000:02:35.350 resets the power and it's perhaps it's 00:02:37.53000:02:37.540 in a lockout if it overheats so many 00:02:39.47900:02:39.489 times the furnace will go into a lockout 00:02:41.52000:02:41.530 where it just sits there for three to 00:02:43.08000:02:43.090 five hours and just does absolutely 00:02:44.72900:02:44.739 nothing so I tell my wife all right shut 00:02:46.89000:02:46.900 down the furnace power switch leave it 00:02:49.02000:02:49.030 off for like five seconds and turn it 00:02:50.85000:02:50.860 back on does the furnace do anything 00:02:52.62000:02:52.630 different so she did that turns the 00:02:55.08000:02:55.090 power back on and still nothing you know 00:02:57.90000:02:57.910 nothing up here works but the fan turns 00:02:59.88000:02:59.890 on and that control board is still 00:03:01.89000:03:01.900 blinking four blinks 00:03:03.18000:03:03.190 so what happened in my case is my 00:03:05.03900:03:05.049 furnace was overheating for probably 00:03:07.47000:03:07.480 like a week or so by now I was actually 00:03:11.18000:03:11.190 forgetful and I forgot to change my 00:03:13.71000:03:13.720 filter for probably like two or three 00:03:15.50900:03:15.519 months I usually change it every month 00:03:17.52000:03:17.530 and a half and my filter it doesn't look 00:03:20.13000:03:20.140 that dirty but I guess we've been 00:03:22.77000:03:22.780 burning some candles lately and the 00:03:24.87000:03:24.880 residue from the candles for some reason 00:03:26.91000:03:26.920 just plugs these filters up with this 00:03:29.09000:03:29.100 waxy feeling stuff I guess it's 00:03:31.41000:03:31.420 literally just the wax from the candles 00:03:33.25900:03:33.269 but that really plugs up filter so if 00:03:35.81900:03:35.829 you burn a lot of candles make sure you 00:03:37.35000:03:37.360 replace their filters every month but 00:03:39.81000:03:39.820 anyways I forgot about my filter for 00:03:41.52000:03:41.530 probably like three months so my furnace 00:03:44.28000:03:44.290 was overheating and the way that switch 00:03:46.71000:03:46.720 works it's two different kinds of metals 00:03:48.93000:03:48.940 and they're made out of different 00:03:50.25000:03:50.260 materials so if for some reason your 00:03:52.68000:03:52.690 furnace is getting too hot one of those 00:03:54.90000:03:54.910 metals will 00:03:55.59000:03:55.600 warp and separate from the other one and 00:03:58.26000:03:58.270 as you can see right here the switch 00:04:02.22000:04:02.230 only has two wires so you know you're 24 00:04:05.52000:04:05.530 volts will go into one side and that 00:04:07.74000:04:07.750 switch is normally closed which means 00:04:09.56000:04:09.570 normally operating furnace this switch 00:04:11.91000:04:11.920 should always be closed power will go in 00:04:14.34000:04:14.350 one side and then come right back out 00:04:16.08000:04:16.090 the other side but if it's overheated 00:04:18.24000:04:18.250 and that bi-metal opened up then that 00:04:20.34000:04:20.350 switch is going to be open and not allow 00:04:22.29000:04:22.300 the circuit to go through and if this 00:04:24.24000:04:24.250 limit switch is open then your igniter 00:04:26.46000:04:26.470 will not glow and your gas valve will 00:04:28.11000:04:28.120 not open but anyway back to my story so 00:04:30.87000:04:30.880 my wife told me is blinking four times 00:04:32.52000:04:32.530 she tried resetting it nothing's working 00:04:34.65000:04:34.660 so being the good technician that I am I 00:04:36.87000:04:36.880 tell her okay no problem 00:04:38.34000:04:38.350 take out the doors and I'll walk you 00:04:39.84000:04:39.850 through it I'll tell you what to do 00:04:41.07000:04:41.080 you'll get it fixed in no time 00:04:42.12000:04:42.130 unfortunately my wife was not as 00:04:44.25000:04:44.260 enthusiastic about digging into the 00:04:45.96000:04:45.970 furnace as I was so she told me no 00:04:47.85000:04:47.860 thanks I'll just put on an extra pair of 00:04:49.41000:04:49.420 socks and wait for you to come home so 00:04:51.27000:04:51.280 of course you know later on that's 6:00 00:04:53.07000:04:53.080 6:30 I come home and within a couple of 00:04:55.44000:04:55.450 minutes I got my furnace back up and 00:04:57.09000:04:57.100 running and in a little bit I will tell 00:04:58.83000:04:58.840 you how I did that but before I do that 00:05:00.84000:05:00.850 just real quickly for those of you who 00:05:03.36000:05:03.370 are interested I'll just show you how to 00:05:05.79000:05:05.800 check that switch with a meter if you 00:05:09.18000:05:09.190 wanted to there's two ways you can check 00:05:11.28000:05:11.290 it one way is to check voltage which is 00:05:15.09000:05:15.100 what I prefer I usually prefer to check 00:05:17.19000:05:17.200 voltages more than resistance but you 00:05:19.20000:05:19.210 can also check the resistance or a 00:05:20.67000:05:20.680 continuity since it's a switch so if you 00:05:23.40000:05:23.410 set your meter to let's get my 00:05:27.69000:05:27.700 flashlight so you can actually see it if 00:05:29.97000:05:29.980 you set your meter to continuity which 00:05:32.82000:05:32.830 is that right there that symbol and 00:05:35.45000:05:35.460 mines magnetic so I'll just flip it 00:05:38.37000:05:38.380 right on here somewhere or maybe even to 00:05:40.38000:05:40.390 the inducer motor and then and then just 00:05:50.40000:05:50.410 unplug the wires both of the wires going 00:05:52.89000:05:52.900 to your high limit switch so you just 00:05:56.52000:05:56.530 have the terminals and with your meter 00:05:59.13000:05:59.140 set to continuity put both leads on both 00:06:02.79000:06:02.800 terminals like this 00:06:06.67000:06:06.680 as you can see my meter is beeping which 00:06:10.51000:06:10.520 means this switch does have continuity 00:06:12.33000:06:12.340 now if this switch was oh L like you see 00:06:15.58000:06:15.590 rate on my meter like that that means 00:06:18.31000:06:18.320 that switch is open or you can just 00:06:20.23000:06:20.240 check the resistance that Omega symbol 00:06:22.87000:06:22.880 or the ohm symbol almost the same thing 00:06:26.67000:06:26.680 put your leads on both terminals except 00:06:30.18900:06:30.199 when you're checking resistance there 00:06:31.48000:06:31.490 won't be any beeping as you can see I 00:06:35.85000:06:35.860 have about 1.8 around 2 ohms of 00:06:41.23000:06:41.240 resistance which is normal for this 00:06:42.87900:06:42.889 switch so I know my switch is closed and 00:06:46.33000:06:46.340 like I said previously it's a normally 00:06:47.89000:06:47.900 closed switch so you should have some 00:06:50.40900:06:50.419 kind of resistance or continuity between 00:06:52.33000:06:52.340 the two terminals so that's how you 00:06:54.33900:06:54.349 check resistance and continuity but the 00:06:56.56000:06:56.570 way I prefer to do it is to check 00:06:58.08900:06:58.099 voltage so you do need to have the power 00:06:59.98000:06:59.990 on for this so turn the power on my 00:07:05.05000:07:05.060 thermostat upstairs is calling for Heat 00:07:06.87900:07:06.889 I had my power switch off the whole time 00:07:08.92000:07:08.930 so the burners aren't on while I'm 00:07:10.57000:07:10.580 talking so there it goes my inducer 00:07:12.67000:07:12.680 motor my igniter is gonna start to glow 00:07:16.30000:07:16.310 my pressure switch is closed so by this 00:07:19.18000:07:19.190 time my high limit should have 24 volts 00:07:23.20000:07:23.210 going through it so if I go from one end 00:07:25.14900:07:25.159 to the other if you look at my meter as 00:07:27.76000:07:27.770 you can see I have zero volts and for 00:07:31.24000:07:31.250 those of you that don't know a switch is 00:07:33.73000:07:33.740 literally just that it's just a switch 00:07:35.68000:07:35.690 almost like a piece of wire so if the 00:07:38.40900:07:38.419 switch is closed you won't have any 00:07:40.68900:07:40.699 voltage drop so no voltage it will be 00:07:43.14900:07:43.159 zero but if that switch is open you will 00:07:46.36000:07:46.370 have around 27 volts so for example if I 00:07:49.42000:07:49.430 keep one lead on one terminal and put 00:07:51.90900:07:51.919 the other lead to ground and what I mean 00:07:54.07000:07:54.080 by that is just any screw that's 00:07:55.65900:07:55.669 attached to the furnace cabinet 00:07:57.52000:07:57.530 so for example I'll just go right to the 00:07:59.65000:07:59.660 sky limits true as you can see I have 26 00:08:03.67000:08:03.680 point 4 volts coming in and if I go to 00:08:05.92000:08:05.930 the other terminal 00:08:08.86900:08:08.879 like that I have 26.4 volts coming out 00:08:13.02900:08:13.039 that way I know that the switch is 00:08:15.49900:08:15.509 closed so once again when checking 00:08:17.89900:08:17.909 voltage you just put your leads on both 00:08:20.57000:08:20.580 terminals and if the switch is closed 00:08:23.60000:08:23.610 you'll have zero volts if it's open you 00:08:26.44900:08:26.459 will have twenty six volts so that's how 00:08:28.85000:08:28.860 you check it with the meter now on to 00:08:30.64900:08:30.659 the part of how I actually fixed it 00:08:32.48000:08:32.490 fixing this is actually pretty easy so 00:08:34.73000:08:34.740 basically that switch is stuck open a 00:08:36.80000:08:36.810 lot of times if you just smack it a few 00:08:39.11000:08:39.120 times that'll be enough to cause those 00:08:41.02900:08:41.039 two metals to come back together so in 00:08:43.33900:08:43.349 my case I just took a screwdriver and it 00:08:45.80000:08:45.810 was enough to just whack the limit just 00:08:49.06900:08:49.079 on the faceplate right here just a 00:08:51.41000:08:51.420 couple whacks or good whacks 00:08:52.81900:08:52.829 I just want pam pam pam pam pam i reset 00:08:56.38900:08:56.399 my furnace turned it back on and 00:08:58.24900:08:58.259 everything lit right back up so it was a 00:09:00.25900:09:00.269 really quick fix now sometimes if it's 00:09:03.59000:09:03.600 really stuck open you have to take that 00:09:05.93000:09:05.940 switch out and I'll just show you quick 00:09:08.78000:09:08.790 so you know what it looks like inside 00:09:12.10000:09:12.110 sometimes you have to take it out and 00:09:14.36000:09:14.370 give it a couple of good whacks with the 00:09:18.05000:09:18.060 high-limit out and I have had a couple 00:09:20.48000:09:20.490 times where no matter how hard you hit 00:09:22.75900:09:22.769 it the thing does not close back up in 00:09:25.16000:09:25.170 that case you just have to replace the 00:09:26.66000:09:26.670 high limit so anyways I took out the two 00:09:29.05900:09:29.069 5/16 screws and let's take my switch out 00:09:33.85000:09:33.860 this is what mine looks like it has 00:09:36.53000:09:36.540 usually it'll have some insulation on 00:09:38.26900:09:38.279 the inside and then here's that bi-metal 00:09:41.15000:09:41.160 part that I was talking about you can't 00:09:42.86000:09:42.870 really see the two metals inside they're 00:09:44.48000:09:44.490 all internal but basically here's the 00:09:46.91000:09:46.920 sensor which is usually facing downwards 00:09:49.30900:09:49.319 and on most high limits this will just 00:09:51.62000:09:51.630 be two prongs mine has a plastic casing 00:09:54.23000:09:54.240 it's just an older furnace not a lot of 00:09:56.42000:09:56.430 furnaces will have this plastic casing 00:09:58.10000:09:58.110 and some of them there's different 00:09:59.68900:09:59.699 lengths some of them are a lot longer 00:10:01.22000:10:01.230 maybe like up to here but yeah this is 00:10:03.67900:10:03.689 the high limit it's nothing too 00:10:05.50900:10:05.519 complicated 00:10:06.23000:10:06.240 so if hitting it on the face does not 00:10:09.47000:10:09.480 close it up for you you can try taking 00:10:11.21000:10:11.220 it out and just just 00:10:14.68000:10:14.690 against your furnace or against the 00:10:17.38000:10:17.390 floor not too hard just firmly - trying 00:10:21.07000:10:21.080 to close that back up and almost all the 00:10:23.17000:10:23.180 time that is enough to close that thing 00:10:25.15000:10:25.160 back up and your furnace will start back 00:10:27.16000:10:27.170 up well and that's how you manually 00:10:29.20000:10:29.210 reset that high limit switch in my case 00:10:31.96000:10:31.970 it was a dirty filter and most of the 00:10:33.85000:10:33.860 time that's what it is your filter is 00:10:35.65000:10:35.660 just dirty but there is a lot of other 00:10:37.69000:10:37.700 things that can cause your furnace to 00:10:39.16000:10:39.170 overheat I won't go into that in this 00:10:41.20000:10:41.210 video but I am planning and making a 00:10:43.00000:10:43.010 video right after this one on ten 00:10:45.10000:10:45.110 reasons why your furnace can overheat so 00:10:47.50000:10:47.510 if your problem is not a filter then you 00:10:50.29000:10:50.300 can go ahead and check that video out 00:10:51.46000:10:51.470 for more ideas of why your furnace keeps 00:10:53.92000:10:53.930 overheating and just one more thing I 00:10:55.45000:10:55.460 want to mention a lot of times people 00:10:57.25000:10:57.260 they read their code and it says high 00:10:59.38000:10:59.390 limit open the first thing they do is 00:11:01.27000:11:01.280 replace that limit switch just so you 00:11:03.58000:11:03.590 know it's very rare that that limit 00:11:05.62000:11:05.630 switch fails doesn't happen a lot at all 00:11:08.20000:11:08.210 usually it's just doing its job and it's 00:11:10.45000:11:10.460 opening up because the furnace is 00:11:12.04000:11:12.050 overheating so you have to figure out 00:11:13.54000:11:13.550 why it's overheating and get that fixed 00:11:15.76000:11:15.770 or cleaned up and that is all I had for 00:11:17.95000:11:17.960 this video today I hope you found this 00:11:19.69000:11:19.700 information useful thank you so much for 00:11:21.70000:11:21.710 watching this video don't forget to mash 00:11:23.20000:11:23.210 that like button on the way out and 00:11:24.67000:11:24.680 we'll see you next time and for those of 00:11:27.55000:11:27.560 you that are still here I want to show 00:11:28.93000:11:28.940 you some brownies that a customer gave 00:11:30.49000:11:30.500 me he tells me hey you want some 00:11:32.47000:11:32.480 brownies they're high in fiber and low 00:11:34.42000:11:34.430 in calories and low in fat they're very 00:11:36.85000:11:36.860 great you want some and I say yeah sure 00:11:39.07000:11:39.080 I'll have some so he brings him out to 00:11:40.87000:11:40.880 me and he hands me these brownies 00:11:53.02000:11:53.030 [Music]
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