Troubleshoot T9 Honeywell Thermostat
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Troubleshoot T9 Honeywell Thermostat
Picture #1 shows only 4 wires connected to the old thermostat with no C wire. Behind the wall there is a blue /white wires and brown/red wires appears to be coming from the humidifier. Picture #2 is inside the furnace. Blue and brown wire were cut to ends. Picture #3 is where they connected the humidifier. How do I connect my new T9 Honeywell thermostat with this setup? Thanks in advance!
Last edited by PJmax; 06-26-22 at 03:23 PM. Reason: resized/enhanced pics
#2
Welcome to the forums.
If that was a pro that did that wiring.... fire him ASAP.
We see four wires connected to the thermostat and the same four wires at the furnace.
No idea where the brown and blue are going. They must be spliced somewhere else.
That six wire cable should be from the thermostat to furnace......only.
Since we don't know what is going on with the brown and blue wire wires... you can't use them.
That is a poor way of connecting devices.
You need a C wire. It's there but not there.
If that was a pro that did that wiring.... fire him ASAP.
We see four wires connected to the thermostat and the same four wires at the furnace.
No idea where the brown and blue are going. They must be spliced somewhere else.
That six wire cable should be from the thermostat to furnace......only.
Since we don't know what is going on with the brown and blue wire wires... you can't use them.
That is a poor way of connecting devices.
You need a C wire. It's there but not there.
#3
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Sadly it was a pro that installed the humidifier :-( just bought the house last Friday and was excited about installing a smart thermostat then I run into this SMH
Picture attached is what’s behind the wall.
Picture attached is what’s behind the wall.
#4
That's not a picture of the same thermostat.
The first picture doesn't show a blue wire while that one does.
What is the two wire cable for.... an on the wall humidistat ?
The first picture doesn't show a blue wire while that one does.
What is the two wire cable for.... an on the wall humidistat ?
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The blue wire and brown wires have always been there just behind the wall with the old thermostat. What I did was just transfer the 4 wires to the new thermostat. The 2 wire cable appears to be the humidifier.
#6
Yes... I see that. That's why I enhanced the dark pictures.
I see blue and brown connected from the cable to the humidifier.
What are the blue and brown wiring doing at the thermostat ?
What is the two wire cable in the wall for ?
If that blue wire is not connected then there is no power to the humidifier.
When I look at the furnace wiring I see an extra two wire cable connected to W and B/C.
That should be the humidifier. If it was.... there would not be a reason to cut that cable like that.
Unfortunately you'll need to check further.
I see blue and brown connected from the cable to the humidifier.
What are the blue and brown wiring doing at the thermostat ?
What is the two wire cable in the wall for ?
If that blue wire is not connected then there is no power to the humidifier.
When I look at the furnace wiring I see an extra two wire cable connected to W and B/C.
That should be the humidifier. If it was.... there would not be a reason to cut that cable like that.
Unfortunately you'll need to check further.
#7
Hi, with humidifier out of the picture the thermostat conductors look like they are configured correctly, now you have to concentrate on the humidifier, looks like 2 conductors are going into the duct work?, I would remove anything connected with the humidifier and start over, post pics of which conductors go where.
What is the exact mdl# of the Tstat, where is the humidistat located?
Geo🇺🇸
What is the exact mdl# of the Tstat, where is the humidistat located?
Geo🇺🇸
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Is the humidifier not working is that what you’re saying? Let me know if I need to take anymore pictures.
Last edited by PJmax; 06-27-22 at 09:03 PM. Reason: removed unneeded/resized pics
#9
I customized the pics as needed.
Ok.... you have an Aprilaire 760 humidifier.
It plugs into 120v and may have it's own internal 24v transformer for control.
It needs a contact closure. So what the tech did was to send the two humidifier wires up to the stat/h'stat location on blue and brown. The humidistat closes the circuit.
One more thing..... can you follow the cable that connects to R and W with the question mark and see where it goes. It looks like it should be power for the humidifier because the humidifier needs to know when the furnace is firing. Once I know that we'll go on.
Ok.... you have an Aprilaire 760 humidifier.
It plugs into 120v and may have it's own internal 24v transformer for control.
It needs a contact closure. So what the tech did was to send the two humidifier wires up to the stat/h'stat location on blue and brown. The humidistat closes the circuit.
One more thing..... can you follow the cable that connects to R and W with the question mark and see where it goes. It looks like it should be power for the humidifier because the humidifier needs to know when the furnace is firing. Once I know that we'll go on.
#10
Hi, are you still having problems? That humidistat should only have 2 conductors going directly back to the humidifier, nothing should be attached to the thermostat, find the other end at the furnace, you may need to install a relay connected across W1 at the furnace to control the humidifier when there is a call for heat, so it should work like this, humidistat calls for humidity, as long as there is a call heat the the humidifier will run, or if there is a call for heat and not humidity the heat will come on. That humidifier appears to have its own power supply and shouldn’t be mixed with the furnace 24 VAC power.
Geo🇺🇸
Geo🇺🇸
#12
Geo... there is a relay already connected to the thermostat via C and w.
There is a relay being driven by the call for heat.
What does the relay control ?
Possibly the receptacle where the humidifier is plugged in.
You may not be able to answer that.
We're finding more and more issues.
There is a relay being driven by the call for heat.
What does the relay control ?
Possibly the receptacle where the humidifier is plugged in.
You may not be able to answer that.
We're finding more and more issues.