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I am confused on this schematic drawing and understanding what it means when I see the T1 coil in parallel (I'm not even sure) with the PR1 contact?

Does that mean they are logic "OR"ed together or something else entirely?

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    \$\begingroup\$ Yes, T1 OR PR1, Relay PR1 (6) closes contacts PR1 (8) to take Timer? T1 out of the circuit. \$\endgroup\$ – StainlessSteelRat Apr 28 at 21:28
  • \$\begingroup\$ note that PR1 contacts connect to the body of T1 not to the supply lines of T1 \$\endgroup\$ – Jasen Apr 28 at 23:53
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The PR1 contact should not truly be connected in parallel with the T1 coil:

If it were, energizing coil PR1 (e.g. by pressing the "FIRE" button) would short Line and Neutral and blow the fuse.

Most likely device TR is not a typical relay (or even a typical timer relay). It's always connected to L and N, so always energized.

Most likely the two extra terminals on TR control it's behavior. Maybe it is a reset or start input to initiate a timer interval?

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  • Pressing FIRE energises relay PR1.
  • T1 (Timer 1) is always powered. A contact of PR1 starts the timing function. Note that the contract wires do not connect with the L1 and N wires so it's not in parallel with the timer"coil".
  • When the preset time has expired T1's contact closes and turns on TRC1, etc.
  • Releasing the FIRE button releases PR1, resetting the timer and opening contact T1.
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