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BillyHvac
BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22678
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I just purchased a RTH8500 wifi thermostat and am attempting

Customer Question

I just purchased a RTH8500 wifi thermostat and am attempting to install. Unfortunately, my old thermostat has only four wires and no "C" wire. I put the old "G" in the "C" slot and the "Y" and "W" in the designated slots. My other wire was marked "RH". There is no terminal with that designation so i put it into the "R" slot. I left the "jumper" loop from the other "R" terminal as instructed.
The red light on the thermostat comes on but the screen is blank. That was the other problem. After initial start up the screen lit and i began programing per the instructions. The screen keep fading out and before i was done it was completely blank and has never come back on.
Can you help.
Submitted: 2 years ago.
Category: HVAC
Expert:  BillyHvac replied 2 years ago.
Hello,
in the furnace...did you move green wire to C?
Did you install a short jumper Y to G in furnace on circuit board?
Billy
Customer: replied 2 years ago.
No, i did neither. I can do the jumper from "Y" to "G". Now i have one from "C" to "G". I need to move the wire in the furnace as well??
Expert:  BillyHvac replied 2 years ago.
At thermostat
red to R
white to w
yellow to y
green to g
at furnace
red to r
white to w
yellow to y
green to c
connect g and y with short jumper/wire
can you do this now?
Expert:  BillyHvac replied 2 years ago.
Have I lost contact?
Are you still there?
Expert:  BillyHvac replied 2 years ago.
If you are done please rate so I can move from active list or it ties up ability to respond to others.
If you have more questions please use reply.
Billy
Customer: replied 2 years ago.
Yes, I tried but that did not work. I got a red flashing light in the furnace and still a blank screen with no light at the thermostat.Thanks, ***** ***** called a technician to come and help. If he cannot get the new one to work, we will reinstall the old thermostat. Thanks for your time.
Expert:  BillyHvac replied 2 years ago.
You likely blew a small fuse on the circuit board when you tried the other combos...replace that 25 cent fuse and you should be fine
Customer: replied 2 years ago.
Thanks, ***** ***** give that a try.
Expert:  BillyHvac replied 2 years ago.
it is on the circuit board and may be a blade type fuse like found in a car
I wish you luck
Customer: replied 2 years ago.
I couldn't find anything like an auto fuse on the control box and don't want to open that up. i will wait for a technician to see if he can get it running.thanks again.
Customer: replied 2 years ago.
Yes, we are done for now. There is nothing more i can do until i get a technician here to assist.Thanks again for the effort.