HELP- Can a Ecobee Thermostat Short out a Furnace Board???


Old 02-06-18, 09:33 AM
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Question HELP- Can a Ecobee Thermostat Short out a Furnace Board???

Good Morning All,

I'm truly in need of some help as I'm Disabled and Freezing here in Chicago due to a Inoperable Furnace.

The main issue is the HVAC guy is saying the "thermostat" has shorted the board and Ecobee is saying this is not in any way possible because it doesn't have any power and even if defective can not short out a board. Who is correct and who is liable?

The back story is I have a Ecobee 3 thermostat which needed a fast stat because I didn't have a c-wire installed back in March of 2017 and it worked perfectly until just before Christmas. The new HVAC guy came and told me the board was out and it was "high end board" so we replaced it. He then began to tell us the problem was the thermostat solely based on the Fast Stat and said we need to have the original installer to come out to service it. After explaining the only completed work by the original installer was to add the Fast Stat to the Furnace because I couldn't descend to the basement and I installed the Unit he backed off some but continued to blame the unit. I'd also had him come back and pull new wires to remove the FS and give me the C-wire and yet I still had the Furnace start grinding and stop working on Christmas Day. When he arrived the next day he went in the basement and I now know hit the power switch, came back up and said there is nothing wrong with the unit and again it said it is the thermostat without any troubleshooting. I had to call him out one other time before this last time where now the burner will not come back on at all. With Ecobee, I have bypassed the thermostat and still nothing. He is suggesting that It is now a money pit and new furnace be purchased and stating that the warranty on the "new" board is voided because it's not defective but was shorted because of the thermostat.

Btw the furnace is working and blowing but it only blows cold air CONTINUALLY


I'm ready to head down to the basement myself as Im technically inclined but trying to await some help to get pictures of the "high end board" and the actual make and model of the unit but trying to get answers as quick as possible
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Old 02-06-18, 09:48 AM
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A thermostat or fast-stat shorting would cause the fuse on the board to blow.

Sometimes a problem is beyond what a tech can figure out so he falls back to being a salesman. Call someone else.
Old 02-06-18, 12:15 PM
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Thanks AStuff for the quick reply and agreed that could have shorted the circuit board and it is housed on the board as well. However, two things, the Fast Stat has been removed since Dec 18th when the Tech added the 6-wire T Stat line and he is claiming the "thermostat" itself has caused the short.

I have continued to research since posting and acquired my make and model. I can't find ANY supporting information where an actual thermostat has shorted a circuit board. I've found info on wiring and the such but not the unit itself.

I also have contacted the original authorized dealer who installed it and they are coming out but I am still interested as I have invested over $1000 with this guy since December.

Furnace Make : Bryant
Model: 312AAV/Jav
Thermostat: Ecobee 3

12/10 - Furnace went out/Called HVAC repair
12/11 - Replaced Circuit Board $$$
12/18 - Added the 6-wire T Stat line $$$
12/25 - Furnace went out/Called HVAC repair
12/26 - Arrived stated "working" / flipped switch
12/29 - Furnace went out/Called Cable company to rule out thermostat/wifi
1/1 - Arrived stated "working"
1/30 - Furnace went out/Called Ecobee
1/31 - Troubleshooting did not work with help/Called HVAC repair
2/1 - Arrived stated "working" / flipped switch /blamed thermostat/ contacted Ecobee together determined some fault and sending out new unit/ Had "restage" unit to temporary hold $$$
2/2 - Furnace went out/Called Ecobee
Called HVAC repair
2/5 - Arrived stated unable to get the pilot to stay on continues to go out when switching to low after a few minutes. States needs "new" thermostat to rule out if board inoperable and began the sales pitch you referred to. Also stated that if inoperable due to thermostat it VOIDS the warranty of the "new" board installed on 12/11
2/5 - Ecobee stated the thermostat doesn't have any power and cant short anything. Stated warranty only covers device and new unit should arrive tomorrow.
2/6 - Found manufacturer and initial installer info made contact and tech scheduled for today
2/6 - Replacement just arrived as I typed response - New Ecobee4
Old 02-06-18, 12:33 PM
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That is a modern furnace that doesn't have a pilot. It does have a status LED on the control board. It would be helpful to know what code it was blinking or if off. You do have to take the front cover off to see it.
Old 02-06-18, 12:56 PM
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Makes since why no one could see a pilot. How can I tell the code it was blinking? It had a green blinking light but I didn't see any codes. I did a short video but not sure if I can post it here, nope I tried to upload it as a zip file but it was still too large.

I do have it here if this helps -
Old 02-06-18, 08:46 PM
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Welcome to the forums.

At DIY..... a topic is contained in a single thread. This is your furnace thread. The other one in thermostats is closed.

I watched the video but cannot tell what it is flashing. I've never seen the fault code LED so bright. Usually you have to squat down and look thru the sight glass. Your service tech can read the stored codes in that board. Since that board has a 3A fuse on it...... there is no way the thermostat caused any problems.

More than likely your furnace is failing on a firing problem. Possibly the flame sensor or pressure switch. Unfortunately I don't have too much faith in your tech.

On page 45 is a description of the service fault codes.
Your furnace manual.... manuals lib/Bryant-312aav-Jav

Last edited by PJmax; 02-06-18 at 09:14 PM.
Old 02-07-18, 11:16 AM
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That bright flashing is not what I'm used to. I assume they replaced the board with something non-standard.

If this is a bigger HVAC company I would talk with the owner/manager and ask to get a senior repair tech out to help. State that you've spent a lot of time and money with them and just want it fixed.

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