Although they are both thermostats.... they couldn't be more different.
You have an FCU (fan coil unit)..... sometimes also known as a PTAC (packaged terminal).
Your thermostat runs on 120v and switches much differently than the 24v model you want to use.
You can only upgrade to another 120v thermostat or major re-wiring work would need to be done.
Those pictures are great but doesn't change the fact that you want to install a 24v thermostat on 120v lines. You can replace that with a new 120v line powered thermostat or you can add relays in your system to convert from 24v to 120v. It's not hard but you need to understand wiring.
If you want to make the conversion... take a picture of the wiring at the FCU.
A picture of the wiring diagram would be helpful too.
Hi guys!
I’m trying to replace my old manual Line Voltage thermostat brand Erie with 4 wires with Honeywell TB6575A1000. Red and blue wire are for fan low and med speed, both on new and old thermostat.
So I’m absolutely sure connecting these two by colours if perfectly fine as they match even by wiring diagram.
However black and white are giving me hard time, as on new thermostat black should be hot and white should be neutral, but on old one white is connected on spot marked as “line” on diagram which I assume should be for 120V. When I measure it with voltmeter it shows constant 120V if unit isn’t of or on.
When I measure black on old thermostat it has 0V unless you turn it on and then it has 120V or so. Moreover, black seems to be connected to high speed fan spot on diagram, but this unit has only 2fan speeds working, although switch is made for 3.
Should I just connected black to black, white to white or other way around. For red and blue, I’m confident those are ok. What are the consequences of wrong wiring in this case?
I have attached all the photos. Fan coil seems to be Luxair L350.
Many thanks for your help!Read More
Hi guys, need pro HVAC help. From reading previous posts I assume I remove the Honeywell THM5421C with its old TH9421C1004 Thermostat and put in-place the Ecobee Premium EB-STATE6-01.
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[*]Does my wiring look correct (basically connect corresponding wires from THM5421C to Ecobee Premium?
[*]How do I connect the Humidifier to Ecobee Premium?
[*]Do I need Honeywell Discharge Air Temp sensor, if yes, how to connect to Ecobee Premium?
[*]My R Rc Rh are jumpered together at the THM5421C. Do I need to do the same between Rc & Rh on Ecobee Premium?
[/list]
My wiring diagram: [url]https://docs.google.com/drawings/d/1NF1TiuuTojO4ZQGY5MmBMi6XWWbyvr-nkAgWCGp0aAI/edit?usp=sharing[/url]
[img]https://cimg8.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x813/my_hvac_e89588a4543eabe2b1a7a43c8ee09de8ea5dd342.jpg[/img]
P.S. I already have an existing 8-wire between the furnace room and the thermostat location
THANK YOU FOR HELPING!!!Read More
02-03-23, 04:24 PM
