gas furnace trips breaker reset breaker and trips after 30 seconds?

dont go buying a bigger breaker. that will result in overheated wires then fire. if it worked before, obviously something happened. you no doubt have a short . often times if the wires touch the furnace or ductwork itll over the yrs wear the jacket off the wires. seen it a few times. with the breaker off, trace the whole wire from box to furnace. could be a bad breaker too. same amps no bigger,

My guess would be a bad blower motor. Could be the the soft start capacitor if there is one. It could also be a problem with the electronic ignition. Both will draw over 15amps when starting if bad. Do not put in a new breaker with a higher number ever. A 15 amp breaker is fine for a gas furnace. If need be I would call a hvac person before a electrician. Good luck.

Either one of two things is gong on. You need a bigger size breaker (check your manual for the furnace). Or you have a wire shorting out somewhere which is causing the breaker to flip. Hope this helps.

May just need to get a bigger amp breaker. Not too expensive most houses in US have 15 I think. You can go to lowes or home depote they got em there and can answer ur q better