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airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8134
Experience:  Furnace, A/C and heat pump specialist.
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I have a new furance(3 Years old) and I just installed a

Customer Question

I have a new furance(3 Years old) and I just installed a nest thermostat. The theromstat says it is heating but it is really not. Since installing the nest the furance has been unpredictable. Fine some days others day not fine
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: Filter is fine. Settings are fine.
JA: Do you plan on doing the work yourself?
Customer: I am not sure what the problem is. We currently have work being done in the basement where our furnace is. Could that cause it to behave erraticly?
JA: Anything else we should know to help you best?
Customer: For example, yesterday..all day it was fine. Last night it decided to shut down and not work. The thermostat says its "heating" but its not.
Submitted: 7 months ago.
Category: HVAC
Expert:  airheatman replied 7 months ago.

Sounds like issue may be with furnace rather than thermostat.Are you able to do some troubleshooting when it says it is on but really is not and do you have a multi meter for troubleshooting?

Customer: replied 7 months ago.
I can. Yesterday it was totally fine. The last night it did not run. We also have had work being done in our basement where the furnace is and it has been VERY dusty. Could that be the problem?
Expert:  airheatman replied 7 months ago.

It is possible if filter gets dirty that might restrict air flow but return grille is probably not in the basement.

When it ails,, look on control board in furnace and see if we have a flashing light on board.We will go from there.

Customer: replied 7 months ago.
I am not at home. But I can look later. Where is the return grill?
Expert:  airheatman replied 7 months ago.

That is where your filter is located usually.It is where air is drawn into furnace.If no filter in grille,it will be in bottom of furnace.

Customer: replied 7 months ago.
Ok. I will check it out. I really dont understand what the problem could be. The thermostat says it is "heating" but it is not actually heating. I had an HVAC person come in and rewired everything so that is fine. It seems that the thermostat is not communicating with the furnance at times. Could that be a wifi problem?
Expert:  airheatman replied 7 months ago.

It is possible, but lets do some troubleshooting when you are there. WE will check between the C and W terminal on furnace control board to verify if thermostat is sending signal to furnace to come on if there are no error codes.

Customer: replied 7 months ago.
Ok, I will be home in about 20 minutes. I will let you know when I get there.
Expert:  airheatman replied 7 months ago.

I may be gone to vote,but will be in and out.

Customer: replied 7 months ago.
How do i know where the c and w terminal are??
Expert:  airheatman replied 7 months ago.

You will see letters by the terminals on furnace board where thermostat wires connect to furnace

Customer: replied 7 months ago.
I dont see any lights on or anything
Expert:  airheatman replied 7 months ago.

OK remove bottom panel and hold door switch in and tll me if you see a light on board

Customer: replied 7 months ago.
Expert:  airheatman replied 7 months ago.

Give me model ob furnace and tell me what light is doing

Customer: replied 7 months ago.
I will have to get back to you a bit later. We are having work done at the moment and I am in the way. Thanks!
Expert:  airheatman replied 7 months ago.

That is fine.Heading out in field on an install. Will be back in office this evening

Customer: replied 7 months ago.
Please let me know when you are available. Thanks!
Expert:  airheatman replied 7 months ago.

I am back in office when ready

Customer: replied 7 months ago.
Green light blinking. York furnace
Customer: replied 7 months ago.
Not sure what model number
Expert:  airheatman replied 7 months ago.

Look in burner compartment for model and tell me patter of flashing

http://i.imgur.com/U8b0GXT.jpg

Customer: replied 7 months ago.
Rgf1l100cp16mp11a flashes green about every 3 secs
Expert:  airheatman replied 7 months ago.

OK that is normal.

Do this. Use a jumper wire or needle nose pliers and touch R and W terminals on board and see if furnace comes on.

http://i.imgur.com/JprQdYv.png

Customer: replied 7 months ago.
It does
Expert:  airheatman replied 7 months ago.

OK but not coming on by thermostat?

Customer: replied 7 months ago.
It does but randomly. If its cold in my house and i go to turn it on it doesnt go but it will randomly kick on a specific times. Ever since we changes to nest theromsate. We had normal one before. No problems
Expert:  airheatman replied 7 months ago.

OK to determine if issue is furnace or thermostat we want to do exactly what we just dis when it should be on and will not come on. If jumping R and W makes it work,but thermostat does not we know issue is the Nest. If not we will heck for an error code indicated by the number of blinks on board.

Customer: replied 7 months ago.
Ok. It is currently on so i will wait until it shuts down.
Expert:  airheatman replied 7 months ago.

THat is fine. Just come back to question at that time

Customer: replied 7 months ago.
Thanks for following up. It was a thermostate issue. We swaped them out now all is fine.
Expert:  airheatman replied 7 months ago.

Great news.Thanks for letting me work with you.If my answer has been polite, professional,and thorough, please click one of the ratings before you go. If you still need help let me know!.Expert is not paid for assisting you until you rate answer.Feel free to follow up for 30 days at no additional cost. Bonus always appreciated if you feel justified.