How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask airheatman Your Own Question
airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 7709
Experience:  Furnace, A/C and heat pump specialist.
16514686
Type Your HVAC Question Here...
airheatman is online now
A new question is answered every 9 seconds

I was switching my thermostats from a regular one to nest. I

Customer Question

I was switching my thermostats from a regular one to nest. I did not switch the furnace off and may have completed the circuit when I was cutting off the 18 Guage wire with a metal clipper. I saw a small fluctuation in my lights. So nest didn't work... Then I put my old thermostat in (which was working before) and now it won't turn on the furnace seems like the fan runs.
Submitted: 1 year ago.
Category: HVAC
Expert:  HVAC Guru replied 1 year ago.

Hello and thanks for using this service, if you have been waiting do not worry or get upset I am just one of the techs on here and I try to get to as many customers as I can and I just picked up your question now. Please give me time to respond as typing, researching and adding links takes me time to do so please be patient and often I will ask you questions to narrow down the issue to get is diagnosed correctly.

Expert:  HVAC Guru replied 1 year ago.

Can you get to the furnace and check the board inside the furnace, there is a slot fuse on the board that likely blew like this

CLICK HERE

We are on the honor system for our time, all I ask is please rate my service using the STAR RATING SYSTEM at the top of your page before you leave. If you are not happy with the service please let me know before leaving a negative rating. This is the only way I am paid or credited through the site for my time. This will also allow you to get directly back to me for FREE follow up questions and tips are greatly appreciated! Thanks

Customer: replied 1 year ago.
Fuse is good, checked
Customer: replied 1 year ago.
I also jumped the r and w on the stat and the furnace didn't fire up. Fan works when turned on. When I jump r and W on furnace it fires up.
Expert:  HVAC Guru replied 1 year ago.

OK if it fires up at the furnace, but not at the thermostat the wire is broken between the two.

Customer: replied 1 year ago.
I had to extend the wire using wire nuts as I had to Kobe my stat location. U think it gave up there, is there a possibility it shorted
Customer: replied 1 year ago.
Which wires should I be looking for?
Expert:  HVAC Guru replied 1 year ago.

I would check the RED one.....unless the FAN will work at the thermostat then check the W wire.

Customer: replied 1 year ago.
FM works at the thermostat. My furnace is in the attic, and I'm next to it right now. Anything else I need to check b4 I climb down
Expert:  HVAC Guru replied 1 year ago.

Ok if FM works at thermostat and heat does work at unit then yes I would be checking for a bad connection or broken connection on the W wire for sure!

We are on the honor system for our time, all I ask is please rate my service using the STAR RATING SYSTEM at the top of your page before you leave. If you are not happy with the service please let me know before leaving a negative rating. This is the only way I am paid or credited through the site for my time. This will also allow you to get directly back to me for FREE follow up questions and tips are greatly appreciated! Thanks

Customer: replied 1 year ago.
Also the green light on the furnace blinks continuously.
Expert:  airheatman replied 1 year ago.

If the blinking is a heartbeat, furnace is fine and issue is in the wiring. Was a bit confused at earlier posts since you stated that fan works, but expert was concentrating first on the fuse, then on the red wire, then said if fan works, the white wire.(You stated in opening question that fan works).

Lets concentrate on this. Please verify what you mean by "I had to extend the wire using wire nuts as I had to Kobe my stat location"