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Please attach a well focused, close up photo of the wiring diagram glued inside the service panel, the picture needs to be taken from straight on, in very good light.
You can use the paper clip- icon at the right end of the tool bar at the top of this dialog box to attach ithere.,Include a picture of the thermostat wire connections to the printed circuit board in the same area.
If there is no paper clip-icon, look for the '+attachfiles'link at left of your send button.
I can mark it up with instructions.
We can go from there.
Thanks, ***** ***** external humidistat in series with the red wire I show going from Hum on the thermostat to the solenoid valve on the humidifier.
I can show that too if you need it.
Thanks for letting me work with you. When we are finished, if my answer has been polite, professional, and thorough, please locate the 'rate your expert button' and click one of the ratings .If you still need help let me know!. Rating will not increase your charges, nor close the question, but is how I earn my living.
Sorry I forgot to mark the Humidistat this time, its the small blue box
The circle in the big blue box is the water solenoid valve controlled by the two small wires connected to W and C on the furnace terminal strip
R is the 24volt + power to the furnace from the thermostat
Dhum is 'dehumidification' your thermostat must be set up for that, but apparentlly it is not from what you said earlier.
What i sent you will not turn on the heat from the humidistat, it will turn on the humidifier water solenoid whenever there is a call for maximum heat at the furnace terminal strip.
I am 74 years old, not retired yet, I do this for a living, we can go from here anyway you wish. However if you want to do this in order to get both Dehumidification and Humidification you will be best off by a wide margin using the thermostat that was intented to match up with that furnace as shown on their diagram.
an external humidistat will not work for dehumidification, Dehumidification is achieved by running the cooling in a special very low speed fan mode, with the booster heat on etc.
An external humidistat only controls a humidification process.
When you do not have the correct thermostat you only get humidification when 'full heat' is on, that is when W is powered.
If you want humidification at any other time you need to use the thermostat specified shown no the manufacturers drawing.
What you are attempting is something like putting a old mother board into a later model computer, it might work, but you will loose functions.
You have one of the worlds most advanced furnaces there and a thermostat without the needed circuits to control it properly.
W and C do turn on the heater, that is how the furnace is wired, I simply put your humidistat, and humidifier solenoid parallel in that circuit, so that whenever the W (heat) was energized, you would get power to the humidifier circuit as well,
You need the factory specified thermostat to go with that furnace to get full function.
Good idea, if you will kindly rate my advice positively I will hold the question open for any follow up or additional help you might need later, rating will not increase your charges, but is how I earn a living.