Cover plate or heater cover plate on 66 series Weil Mclain boiler oil

panther

It's a round plate in front of the boiler where the hot water goes through what's entailed to replace that plate is that a real nightmare thanks

HVACNUT

If there are hot and cold pipes connected to that round plate, then that is a tankless coil.
If it's just a coil plate with the aquastat well only, that's easier, but in either case, getting the bolts out can be a real fun experience.
What I typically do is spray the bolts liberally with penetrating oil, take a flat chisel and lump hammer and tap the flats of all the bolts, a 3/8 ratchet with 9/16 head. Don't go ape **** on the bolts. Back out as easy as you can. If any bolts snap, then you're screwed. You'll need a good metal drill bit set. Start drilling small, increasing one size at a time. Tap new threads. You'll need to purchase a tap and dye set. I know you can get a tankless coil for your boiler. Not sure if you can get a coil plate only.
Now, instead of doing all that, considering you have a 66 series McLain. It's 30+ years old. Maybe it's time to upgrade your system.

panther

Okay thank you so much your knowledge is appreciated