Originally Posted By: bking This post was automatically imported from our archived forum.
I understand a lot of inspectors remove the gas furnace cover to observe the flame pattern. I believe most covers have a viewing window that is usually not clear enough or positioned to observe the flame pattern and this is the reason for removing it.
I need more information on this practice since most units have a placard that says Do NOT Operate With Cover OFF.
Also, with the cover off, this changes the operating environment for the flame and might cause an incorrect flame pattern or even a rollout condition.
Originally Posted By: smcintire This post was automatically imported from our archived forum.
Hi Bruce, usually the only viewing windows I see are on 90 percent efficient furnaces, on these you can only look through the window. I have never seen any problem with removing the cover for the burner section. If you removed the lower blower section you may see distortion with the flame but doubtful.
Originally Posted By: Gary Reecher This post was automatically imported from our archived forum.
You have to be careful removing some burner box covers to observe flame pattern. There are a couple furnaces out that have fan assist on the on the burner box pushing air into the burner box. The flames will not act properly and may roll out if you operate the furnace with that cover off.
Originally Posted By: kbowles This post was automatically imported from our archived forum.
The viewing window is to be able to see the light on the control board that blinks in a particular pattern depending on what the problem with the furnace is. This pattern tells the technician what to look for when troubleshooting the system. It lines up with an LED light on the board if you look under it. But once the door is removed the light resets, hence the need to be able to see the light before the door is removed.