What model thermostat is this?

White Rodgers Type 1F82-261

Low end thermostat...recent install and who installed?

thermostat has fan on and fan auto setting?

IMO

Well, you have a G (green) wire connected which should activate the fan if the thermostat tells it to. The fact that the fan won't come on when you move the button to "ON" suggests a wiring problem or a thermostat problem.

Here is the furnace side.

defective thermostat or most likely bad wiring...

How do I test the bad wiring theory? I don't have a spare thermostat to see if the thermostat is bad.

Are you leaving the system switch set to either Heat or A/C when you set the fan to ON?

Take a picture of the circuit board in the furnace to show how blower motor leads are hooked to it. Should be at the top of the board.

Do you own a volt meter?

Just because thermostat is 5-6 years old, discontinued, low end... are not valid reasons as to why the fan on function does not work.

Magic 8 ball says: Need more information.

I t looks like the green wire is going to the G terminal on the control board. The G terminal is energized if the thermostat is calling for heating, cooling, or the switch is to to fan. So if the fan if coming on in two out of three cases, then that would seem it is not a wiring issue unless this control board has an unusual set up. It is likely a thermostat issue. If you had a voltmeter you should be able to isolate the problem

To clarify my earlier post, if my thermostat is set to OFF (neither heat nor cool) the ON/AUTO fan control has no effect. I.e. My thermostat must be set to HEAT or COOL for the fan to be running at all. Is this common among stats? As Austin said, more info is needed (and looked forward to).

I leave the heat or cool function on when I switch the fan control from Auto to on. So I don't turn the thermostat features off when trying to use the fan manually. I'm not sure what other picture would be needed. I sent a picture of the control board. is there a particular section that I should zoom in on? I believe I do have a voltmeter in my tool bag. I will need to check when I get home.

To clarify my earlier post, if my thermostat is set to OFF (neither heat nor cool) the ON/AUTO fan control has no effect. I.e. My thermostat must be set to HEAT or COOL for the fan to be running at all. Is this common among stats?

Well, my White Rodgers Tstat (similar vintage) allows the fan to run when the system is set to "off". But it's a Rheem version so I don't know if their proprietary programming would make it behave differently.

Does it run when you have the system set to Heat or Cool and the fan switch on the thermostat to "on" (but the system is not calling for heat or cool)?

OK, just looked at yout Tstat's manual. Two points:

1. "ELECTRIC/GAS JUMPER (Fan Option)
   Read the following information before clipping the nonelectric heat jumper. If you are unsure of your application, contact a qualified service person. If your emergency or auxiliary system will energize the blower, then jumper, W904, on the thermostat base must be cut (see fig. 1). If your emergency or auxiliary heat system requires that the thermostat energize the fan circuit, do not cut jumper W904."
2. "FAN OPERATION 1. Move fan switch to ON position. The blower should begin to operate. 2. Move fan switch to AUTO position. The blower should stop
   immediately."

Sounds like you fan should run with system off and fan on. I don't know what your air handler is set up as but, usually, heatpumps are set to "electric", which means the thermostat controls the fan and the jumper should not be clipped (which it hasn't).

When fan is set to on, instead of auto, it does not run when the setting is cool, off, or heat. Fan only runs on auto when heat or cool is set and triggered.

so to be clear, when you set the fan to on, it does not run and neither does the condenser when in cool or heat and calling for either.

IMO

Tell me about the state of the batteries. Are they new?

Just changed battery. LCD screen stayed on when batteries removed. Put in fresh ones. No change.

Put fan to on. Then triggered heat by raising desired temp above room temp. No fan. Moved fan to Auto. And it started blowing.

BigAd- you say the thermostat came with the house in 2011. Is this a new problem or has it been around as long as you?

Been around as long as me. Have asked my brother for his spare thermostat, but that may be a couple weeks to try out.

I know my thermopride furnace has a switch to keep the fan on behind the service cover above the burner. It means a trip to the crawlspace though

I'm not sure what other picture would be needed. I sent a picture of the control board. is there a particular section that I should zoom in on?

Ah, I just noticed something... but without being there I need to be sure. Take a picture of the top area of the circuit board to the furnace or better yet the whole circuit board - I want to see if there is any motor leads coming from board, among other things...

Before you go up there or where ever it is, put the thermostat to off and put fan to ON position. Take your voltmeter with you and check voltage from 'G' terminal to 'C' (it looks like this might be B/C terminal on your board). Also when you do this power must be on to furnace --- you may need another hand to depress blower door switch while performing this.

If you have 24 volts or more from G to C (BC) do a double check and check voltage from R to G - there it should be 0 volts.

It looks like this blower compartment is that of a gas furnace, with thermostat used for heat pump operation. (if that is the case, there should be another circuit board somewhere commonly called dual fuel kit to cycle between heat pump use versus gas use.) If you see something like this you will need to take pictures of this as well. Remember there is a 'multitude' of configurations... my view is like that of a blind man (in forum board setting - I'm not really blind although my eyesight isn't as good as it used to be).

Will try voltmeter later today. Some pics.

More pics

It's worse than I thought... It's a choo choo. LOL.

With that aside, try to take another pic of the furnace circuit board (top left side) zoom in so I can read the markings on the top of the board in the furnace.

also when you take volt readings get a reading from G1 to blue wire coming off sequencer or what looks like B terminal (blue wire hooked to it) in the fuel kit section. Record these voltages.

Choo choo?!

Here's a pic.

you know the obnoxious thing that rolls down a track, makes a bunch of noise and destroys anything that gets in it's way. LOL.

Ok, the board is as I thought.

I need voltages. Set thermostat to off / fan to on.

Power must be on to furnace make sure the blower door switch is closed.

On circuit board in furnace: take voltage from green wire to known 24v common. (usually blue for trane) check red thermostat wire terminal on board from red to ground to verify you have 24-30 volts. If you have 24v from Red terminal to ground, check red to green... it should be 0 volts.

If it's not 0 volts, go to thermostat check volts (make sure furnace power is ON, the blower door switch must be closed) Check volts from red to common, should be 24 v. check green to common should be 24 volts if you left FAN to ON when you took cover off stat.

Check red to green (on thermostat) should be 0 volts. (w fan switch on).

In the fuel kit area get voltage from G1/ green wire to known 24v common (typically blue for trane) Make sure BLOWER DOOR SWITCH IS CLOSED / Power on to furnace.

Record those volt readings and report back.

Uggh...can't find my multimeter. Will figure that out and get back. Thanks very much for all the advice.

Got the multimeter. OK - dealing with a newbie here (obviously).

I assume the connectors on the furnace I am testing are the ones in the bottom left of the image (wires that are likely connected to the thermostat).

What is the probe touching for "ground" in the above tests you asked me to do?

Where do I find the blower door switch to depress?

Thanks.

The wires to check are at the bottom of the circuit board in the furnace, and the wires in the fuel kit on the plenum.

The blower door switch has silver tape on it, so it should be already jumped out for you unless you removed this tape for some reason. Just make sure the furnace power is on, otherwise it's pointless to do this check.

There should be a 'C' terminal on the circuit board in the furnace at the bottom of the board where all the other thermostat connections are, use that as your common connection. Another good 'C' connection is off the transformer blue wire, but you can't fully disconnect that wire or you will compromise your read.

Note to others reading this: Blue common wires are associated typical with TRANE products. Just because it's blue doesn't necessarily mean it's common connection in all scenarios.

So to clarify, in this instance, the C common connection is serving as ground?

Wouldn't it easier to check the connections on the thermostat first?

All readings came back at 27.3 to 27.5 for R to C or G to C or G1 to common on fuel pump kit. And zero between R and G at thermostat and furnace. Used blue common wire as ground. Blower door switch had tape on it. And setting for testing was off on thermostat with fan set to on.

What does that tell you?

Blower motor not running at all? If the blower motor works in other modes such as call for heat or cool, then process of elimination would say control board.... however this needs to be verified. That is beyond the scope of what a home owner can do.

With that said, this is why we don't blame a thermostat because it is low cost, not manufactured any more model.

OK. Thanks for all the help. Will get an HVAC Pro out at some point to have a look.

I'm back. With a new question. Please humor me.

I got an ecobee3 lite over the holidays and have installed it. It seems, however, that when it gets too cold for the heat pump to run, aux stage 1 on my Trane XV80 kicks in and then some minutes later aux stage 2 kicks in. I'm guessing it was the same with my old thermostat. Looking at the furnace control board picture, ecobee support says this is because W2 is jumpered to W1. So the ecobee can't control the stages. They also don't see where the black E wire from the old thermostat goes on the furnace.

Question 1: Looking at the pics above, can you tell me where the black E wire goes and whether it has any control over the aux heat stages? Does it go to the heat pump kit control board?

Question 2: Is there anything I can do to give the thermostat control over aux heat stages? I'm guessing just removing the jumper on the furnace control board between W1 and W2 is not enough.

Thanks, and happy new year.

nope, you have to hunt it down and find out where it goes.

Where do you have the black wire connected to on the new thermostat?

The E wire terminal was used as an emergency heat relay on your other thermostat.

On the new one it connects to W2, but ecobee support says it won't work for that purpose because it was connected to the emergency heat relay on the old thermostat. That's why they want me to tape it and set it aside. When I do so, I only have the white wire going into W1 on the ecobee and ecobee recognizes the furnace as only a 1-stage furnace. So, I guess when it calls for aux heat, the furnace (which has W1 and W2 jumpered) will trigger aux1 heat and then a few minutes later it calls for aux2 heat.

So you know what you need to do.... right?

Ummm....nope!

Control<<<<<<<<<<---------------WIRE--------------------->>>>>>>>>Relay (Load)

The voltage between the R and B terminal in the thermostat should be about 24 volts AC (It can be in the range of 20 to 30 volts AC.) This is the input power to the thermostat. Make sure your meter is set to AC volts not DC volts, qnd then test this. When the fan switch is on, the green terminal should be about 24 volts AC compared to the B terminal and zero volts AC compared to the R terminal. If this is not true, the thermostat is defective. If this is true, check the voltage at the G terminal on the control board inside the furnace.