Furnace on for a few seconds then turns off.

Old 01-24-13, 07:36 AM
Thread Starter
Join Date: Jan 2013
Location: Canada
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Furnace on for a few seconds then turns off.

Concord 90 plus high efficiency gas furnace

Furnace kicks in, glows orange. See the flame start up. A few seconds later it shuts down.

After googling I thought it was the flame sensor. I took it out and cleaned it, put it back in and the first couple times it still didn't worked. I think the third time it worked and stayed on. Thought it was fixed for good. Stayed working for 2 days.
Last night I decided to clean my mess up since I didn't the other day. Put the tools away, and put the furnace door back on. Woke up this morning and it was 15degrees C/ 59degrees F inside the house!!

Took the cover off again, looked at it and same exact issue. Furnace kicks in, glows orange, flickering flame for like two seconds then shuts down.
This time I looked at the error code. Didn't think about that before.

flashed 3 times: "pressure switch open with inducer on"

From the look of the flame flickering I think its not getting enough air. So this time I open the front cover door, and I take off the combustion box cover which exposes the burners etc. (didn't do this last time) I turned the furnace back on, let it kick in and watched very carefully. Not exactly sure if this cover is ok to be left off temporarily or not but there is no warning on it. Figured I could run to the switch if I had to. lol
So it kicked in and the flame looked good and it started up just fine.

Turned off the furnace and put the combustion box cover back on. Turned it on and same problem.

Turned off the furnace and took the combustion box cover back off. Tried it and it worked. So every time that cover is off it always works.
While it was still running I looked at the flame colour. Nice blue, as I put the combustion box cover back on it started getting a blue/orange flame. When I put the cover on completely and tight it turned really orange and flickering and then shut down the furnace.

Must have to clean/clear out something? where do I start?

Old 01-24-13, 01:04 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,499
Likes: 0
Received 1 Like on 1 Post
You have something plugging up the air flow through the furnace. That could be in the air intake pipe, the furnace itself, the vent pipe or the condensate line that carries water away from the furnace.

I'd start by testing to see if disconnecting the air intake line at the furnace allows the furnace to operate.

Check to see if the drain line out of the furnace is draining water away from the furnace. The drain line can freeze up or become plugged with debris.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: