York furnace PCMD LD 16N095B, EMAM 409779

This is one of those old-style limit switches that also
turns on and off the fan via temperature. Fan on/off
temps are adjustable. Limit switch is anchored, I think
at about 150. Supply air just on the other side of the furnace.
I didn't have much choice about where to take it as the air
handler was right up against the floor. Anyway, when
the supply air was about 107, the limit switch opened
once or twice. Other times, it ran for a long while without
opening.

My BIG question is the limit switch heater. That's what
it says. There are two terminals in the middle of things
just to the side of the dial, and they are run to the gas
valve. In the schematic, it says the heater is only on some
models. York says the particular one is obsolete and
wanted to know the lenghth. Well, I didn't remove it
to measure because I thought York would have a replacement
so I didn't know the length. But I have a couple of sizes of
Honeywell ones on my van but they don't have heaters.
So what is the purpose of the heater and can I likely
use a fan/limit withOUT a heater with no ill effects?
(The Honeywells also allow adjustment of the limit temp.)

Thank you.