Furnace problem? 3 weeks ago my gas furnance made loud banging thud along with...

3 weeks ago my gas furnance made loud banging thud along with flame shooting upward instead of going directly into ductwork.

I shut the emergency switch past its sell-by date and turned it back on. It works fine.

Than today contained by the morning it happened again.

Please assistance!! I have few skill in HVAC and don't want to call tech. right away unless I know it something I can't fix it myself.

Thanks
Is it possible to use a gfci on...
Answers:    sounds resembling the damper in your flue is sticking. combustion nouns issues. may have to ring up a plumber
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HVAC tech contact me at pete0518jr@optonline.net