Distance from the sun for tidally locked world

[stevebowers]

If the system is stable, the red dwarf B must either be in a P-type orbit, where the planet orbits both stars (which are very close together) or an S-type orbit, (where the planet orbits one star, and the other is at least three times as far away). If you are describing an S-type system, the red dwarf will be at least 3 times as far away from the planet as the primary, so it will have only a minimal effect on the planet's weather (although it could make the nights appreciably warmer and brighter on occasion).
see
http://www.orionsarm.com/eg-article/460d90f53fb24