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Thermostat Wiring Diagrams! 10 Most Common!

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Language: en

00:00:01.680
hey guys this is Craig McClatchy with EC
00:00:04.010 00:00:04.020 super speck and today we're going over
00:00:05.510 00:00:05.520 our common low voltage thermostat wiring
00:00:07.789 00:00:07.799 diagrams so I'm going to be going over
00:00:09.530 00:00:09.540 some of the furnace and air conditioning
00:00:11.629 00:00:11.639 thermostats and then also the heat pump
00:00:13.730 00:00:13.740 thermostats so here you see we have the
00:00:15.799 00:00:15.809 low voltage color code for connecting a
00:00:17.600 00:00:17.610 thermostat to a furnace and not all
00:00:19.580 00:00:19.590 systems are going to be wired this way
00:00:20.840 00:00:20.850 for when you're replacing a thermostat
00:00:22.520 00:00:22.530 so that's very important that you go
00:00:23.990 00:00:24.000 ahead and note which wires were
00:00:26.060 00:00:26.070 connected to which terminals before you
00:00:27.560 00:00:27.570 go ahead and replace that thermostat if
00:00:29.150 00:00:29.160 you don't know where they were connected
00:00:30.170 00:00:30.180 before you can go ahead and turn the
00:00:31.430 00:00:31.440 power off to the furnace and check in
00:00:33.500 00:00:33.510 the inside and note where each of those
00:00:35.720 00:00:35.730 wires are connected to at the furnace
00:00:37.669 00:00:37.679 control board so this is generally what
00:00:39.709 00:00:39.719 you're going to see when you find a
00:00:40.880 00:00:40.890 wiring diagram in a thermostat manual or
00:00:43.759 00:00:43.769 a furnace manual so they're just gonna
00:00:46.069 00:00:46.079 be black and white so you just got to
00:00:47.959 00:00:47.969 connect w2w or tour you see that we have
00:00:50.930 00:00:50.940 a jumper from our to our C and that's
00:00:53.959 00:00:53.969 because R is for your heat and our C is
00:00:57.079 00:00:57.089 for your air conditioning so when you
00:00:59.000 00:00:59.010 turn your thermostat to fan it's or C
00:01:01.279 00:01:01.289 that connects to G or if you turn your
00:01:03.469 00:01:03.479 air conditioning on its or C that
00:01:05.720 00:01:05.730 connects to Y and G when you turn your
00:01:09.200 00:01:09.210 thermostat on for Heat it's or that
00:01:11.810 00:01:11.820 connects to W so that's why when you
00:01:13.670 00:01:13.680 have a furnace and air conditioning
00:01:15.170 00:01:15.180 system you have a jumper connected from
00:01:16.880 00:01:16.890 R to R C but you only need to have one
00:01:19.190 00:01:19.200 wire coming out of one of the or
00:01:21.530 00:01:21.540 terminals on the thermostat you're going
00:01:23.300 00:01:23.310 to notice that C is wired so you are
00:01:25.730 00:01:25.740 hard powering the thermostat in this
00:01:27.290 00:01:27.300 wiring diagram you can wire the system
00:01:30.500 00:01:30.510 up with only four wires instead of five
00:01:32.390 00:01:32.400 wires shown here if you have batteries
00:01:34.160 00:01:34.170 and the thermostat then you don't have
00:01:36.110 00:01:36.120 to wire up that C terminal I also want
00:01:38.630 00:01:38.640 you to note where the yng wires are
00:01:41.600 00:01:41.610 jumping over top of that or C wire so
00:01:44.780 00:01:44.790 they are not touching the or C wire but
00:01:46.910 00:01:46.920 they are jumping over top of it if it
00:01:48.770 00:01:48.780 were just a straight line intersecting
00:01:50.360 00:01:50.370 with our C then that means it's
00:01:51.650 00:01:51.660 connected and here you have a wine
00:01:53.120 00:01:53.130 diagram for a furnace note that you
00:01:55.430 00:01:55.440 don't have any wire on the Y terminal
00:01:57.470 00:01:57.480 and it's up to the Installer whether
00:01:59.390 00:01:59.400 they're going to wire up the g terminal
00:02:01.190 00:02:01.200 the g terminal in this case would only
00:02:03.920 00:02:03.930 be used if the the thermostat was turned
00:02:06.470 00:02:06.480 on for the fan option just to circulate
00:02:09.259 00:02:09.269 air through the building but that G wire
00:02:11.089 00:02:11.099 is not needed to provide heat in the
00:02:12.920 00:02:12.930 building because the furnace will
00:02:14.630 00:02:14.640 control
00:02:15.350 00:02:15.360 when that blower turns on after the heat
00:02:17.630 00:02:17.640 exchanger heats up during a teat
00:02:19.040 00:02:19.050 sequence so you could wire this just
00:02:21.320 00:02:21.330 with the our wire the W wire and then
00:02:23.960 00:02:23.970 the optional C wire C wire would be used
00:02:26.690 00:02:26.700 to hardwire the thermostat instead of
00:02:28.280 00:02:28.290 using batteries here we have a wiring
00:02:29.930 00:02:29.940 diagram for an air handler and AC in
00:02:31.670 00:02:31.680 this thermostat is the same one used for
00:02:33.920 00:02:33.930 a furnace and air conditioning system we
00:02:35.750 00:02:35.760 just don't have to wire the W wire
00:02:37.460 00:02:37.470 because there is no heat on this one
00:02:39.230 00:02:39.240 it's just an air handler for air
00:02:41.120 00:02:41.130 conditioning only note that you don't
00:02:42.800 00:02:42.810 have to have a jumper between our and
00:02:44.570 00:02:44.580 our C because there is no heat now in
00:02:46.700 00:02:46.710 this wiring diagram you can see that the
00:02:48.170 00:02:48.180 thermostat is different this is a heat
00:02:49.790 00:02:49.800 pump thermostat with the E and aux now
00:02:52.550 00:02:52.560 once again we don't have any heat so you
00:02:54.590 00:02:54.600 don't have to have anything wired to the
00:02:56.390 00:02:56.400 E or the aux terminal the oh is for the
00:02:59.060 00:02:59.070 reversing valve for a heat pump so we
00:03:00.470 00:03:00.480 don't have to have that wired on either
00:03:02.120 00:03:02.130 here's a wiring diagram for an air
00:03:03.800 00:03:03.810 handler with electric resistance heat
00:03:05.270 00:03:05.280 and air conditioning this uses the heat
00:03:07.130 00:03:07.140 pump thermostat and the reason we're
00:03:08.600 00:03:08.610 using that is to make sure that when or
00:03:10.520 00:03:10.530 powers e for the emergency heat it's
00:03:13.280 00:03:13.290 also going to power G for the fan but
00:03:15.470 00:03:15.480 it's not going to turn on the outdoor
00:03:17.210 00:03:17.220 air conditioner when the thermostats
00:03:18.800 00:03:18.810 calling for cooling it's gonna then
00:03:20.390 00:03:20.400 connect our C to the Y and G for air
00:03:22.640 00:03:22.650 conditioning note that the ox is not
00:03:24.380 00:03:24.390 wired to the W here's a wiring diagram
00:03:26.870 00:03:26.880 for a air handler and heat pump with no
00:03:29.300 00:03:29.310 electric strip heating and note that you
00:03:31.250 00:03:31.260 don't have the e or the aux wired but
00:03:33.680 00:03:33.690 you do have the O wire and O's for the
00:03:36.050 00:03:36.060 reversing valve to change the
00:03:37.280 00:03:37.290 refrigerant direction in order to
00:03:38.870 00:03:38.880 provide heat inside the building instead
00:03:40.490 00:03:40.500 of the heat removal during air
00:03:42.710 00:03:42.720 conditioning mode now note that you
00:03:44.420 00:03:44.430 don't have to have a wire connecting W
00:03:46.340 00:03:46.350 at the heat pump to W at the air handler
00:03:48.530 00:03:48.540 and the only reason that that's there is
00:03:50.690 00:03:50.700 to send the 24 volt signal from the heat
00:03:53.720 00:03:53.730 pump to the air handler anytime defrost
00:03:55.460 00:03:55.470 is happening at the heat pump but since
00:03:57.320 00:03:57.330 the air handler has no way of providing
00:03:58.880 00:03:58.890 any heat inside the building there's no
00:04:00.949 00:04:00.959 need to have that there now you can wire
00:04:02.840 00:04:02.850 that W from the heat pump to the air
00:04:04.400 00:04:04.410 handler and that will not hurt anything
00:04:05.840 00:04:05.850 00:04:07.520 00:04:07.530 00:04:08.930 00:04:08.940 and a heat pump so this is going to be
00:04:10.970 00:04:10.980 able to provide heat and air
00:04:12.740 00:04:12.750 conditioning as well as to have the
00:04:14.600 00:04:14.610 electric strip heating as a backup for
00:04:16.400 00:04:16.410 the heat pump so you see that o is wired
00:04:18.680 00:04:18.690 for the reversing valve and then you
00:04:19.909 00:04:19.919 have E and aux both wired for the
00:04:22.159 00:04:22.169 electric strip heating and this
00:04:23.779 00:04:23.789 thermostats going to determine whether
00:04:25.310 00:04:25.320 the heat pump can run by itself for heat
00:04:28.010 00:04:28.020 or if it needs a
00:04:29.180 00:04:29.190 the heat pump and the auxilary heat and
00:04:31.310 00:04:31.320 then the e is if you want to just turn
00:04:33.860 00:04:33.870 it to electric strip heating only this
00:04:35.930 00:04:35.940 wire diagram shows the be terminal wired
00:04:38.090 00:04:38.100 instead of the O terminal and that's for
00:04:40.310 00:04:40.320 systems that power the reversing valve
00:04:42.260 00:04:42.270 that they're in heating mode good
00:04:43.940 00:04:43.950 examples of those are rude and reamed
00:04:45.740 00:04:45.750 systems in this case you would not wire
00:04:47.600 00:04:47.610 the terminal you would just wire the B
00:04:49.280 00:04:49.290 terminal here you have a line diagram
00:04:50.720 00:04:50.730 used for an air handler air conditioner
00:04:52.700 00:04:52.710 and boiler so since you have two
00:04:54.650 00:04:54.660 separate systems with separate 24 volt
00:04:56.870 00:04:56.880 transformers you're going to remove the
00:04:58.700 00:04:58.710 jumper between R and RC and this single
00:05:00.830 00:05:00.840 thermostat will control two separate
00:05:03.140 00:05:03.150 systems since this thermostat is
00:05:04.670 00:05:04.680 hardwired for this 24 volt power from
00:05:07.070 00:05:07.080 the air handler anytime you turn the
00:05:09.020 00:05:09.030 power to the air handler off the
00:05:10.880 00:05:10.890 thermostats going to go blank so you
00:05:13.340 00:05:13.350 could have batteries in there instead of
00:05:14.900 00:05:14.910 using the C terminal but this thermostat
00:05:17.330 00:05:17.340 is going to be powered between our C and
00:05:19.310 00:05:19.320 C here's essentially the same wiring
00:05:21.260 00:05:21.270 diagram it's just using a furnace as an
00:05:23.030 00:05:23.040 example instead of a boiler so if you
00:05:24.830 00:05:24.840 had some type of furnace that you're
00:05:26.240 00:05:26.250 powering that was separate from a boiler
00:05:28.370 00:05:28.380 and you use the or W terminals instead
00:05:30.680 00:05:30.690 of the T V and T terminals so here you
00:05:32.690 00:05:32.700 have a wiring diagram for a 750
00:05:34.880 00:05:34.890 millivolt thermo-pile otherwise known as
00:05:36.530 00:05:36.540 a power pile along with the gas valve so
00:05:39.140 00:05:39.150 this is a fairly simple setup used on a
00:05:42.200 00:05:42.210 furnace that does not have a blower
00:05:43.850 00:05:43.860 motor an example of one will be a floor
00:05:46.310 00:05:46.320 furnace I hope these wiring diagrams
00:05:48.200 00:05:48.210 have helped you if you're looking for
00:05:49.520 00:05:49.530 any of the tools I use out in the field
00:05:50.720 00:05:50.730 I have them linked down in the
00:05:51.860 00:05:51.870 description section below if you want to
00:05:53.570 00:05:53.580 help support this each VCR training
00:05:55.159 00:05:55.169 channel click here if you want to
00:05:56.330 00:05:56.340 subscribe click here and if you want to
00:05:57.740 00:05:57.750 see another each VCR training video
00:05:59.270 00:05:59.280 click right here hope you enjoyed
00:06:00.800 00:06:00.810 yourself and we'll see you next time at
00:06:01.909 00:06:01.919 EC service tech channel

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