Question

Logic gates are used to control boiler shut down switch when the temperature reaches limiting temperature and circulating pump is off

Answer 1

It depends upon how the boiler is configured.

High efficiency, modern gas boilers fire at different rates depending on the load. Often, they'll have outdoor sensors which allow them to modulate to low levels when it's warmer outside, allowing them to run efficiently and longer, which, as you've heard, provides more even heating. However they typically won't run all the time.