I need to replace coil in oil burner.

What is the best way to remove rusty bolts from coil in oil burner? Should I soak the bolts with a penetrant like "PB Blaster" for a week? What penetrant do Plumbers prefer for this task? Is there a special tool? Do I just use a socket and a breaker bar? Is there a special technique or process that Plumbers do for removing bolts from the coil?

I believe I will attempt to remove coil in a week or two. Planning ahead.

Thank you very much.

If they were nuts you could heat them or crack them off. But, they are bolts and the real problem is that the rusted ends are where PB Blaster or other stuff may not reach them. So, all you can do is spray the penetrating oil on them and then use a breaker bar and socket to try to unscrew them.

I'd be willing to bet that most of the bolt heads will wring off. I then drill the center out of the remaining stub and use an easy out to remove the rest of the stub.

Yep....Cross your fingers. If they break, I'd use a center punch, to dimple the center of the broken bolt. Then use a center drill to start the hole. They rarely break off flat, and and a regular bit will want to walk on you. Take your time, and try to drill in the center. Easy-outs expand as you turn them, so if you drill to close to the threads, it will lock the "stud" in place.

be patient. I find 2 out of 3 come out.
one thing I do is replace the bolts with studs and nuts.

Use 6 point sockets/wrenches. Soak the bolt with penetrant daily a week or two in advance and use firm hammer blows to the bolt head each time you soak it. The rest is luck.

i just had to remove a 5/16 rusted bolt holding down the battery on my explorer. it was hopelessly rusted. i sprayed it with W/D but it would not budge. i put a socket and extension on my 18V impact driver and rattled away on it a few times. it was not powerful enough to remove it but i think the vibration loosened it enough that the ratchet took it right out.
maybe an impact driver on tankless bolts might have the same result???
(can't hurt)..

Down side to impact wrench: sheared bolt head, but may be worth a try especially if the torque can be regulated.

The shame of it is, it could have been avoided with a nickel's worth of Never-Sieze, at the factory.