Fire elemental power can be seen in different ways, which include and exclude various runes depending upon the way it is perceived. In some of the earlier works about runes, the following runes were given the qualities of fire:
Feoh (primal fire), thurisaz (destructive fire), kenaz (helpful and illuminating fire), nauthiz (needfire), sowelo (sun), dagaz(daylight)
Another method of looking for the qualities of fire is by referencing the various rune poems, for example, in the Anglo-Saxon rune poems the following runes mention fire or flame or flame producing items
Kenaz, (the torch) Eihwaz (a guardian of flame) and qweorth (the fire twirl)
These two are the most common methods by most people of connecting with fire through the runes. After spending some time in contemplationg on this, I came to a third conclusion. The runes of fire by quality. In this case, it has to do with the qualities of fire. Things like radiance, heat, light, will, passion, destruction, are all qualities of fire, qualities which are also reflected in a multitude of runes. Some of these qualities might be more relevant to specific acts of magic, seeking the illuminating quality of fire instead the heating expression might be more useful in a spell to reveal things.
Kenaz – the fire of illumination, passion, inspiration, knowledge
Hagalaz – destructive fire
Sowelo – Fire of radiance, light, warmth, success, victory
Eihwaz – protective fire
Ehwaz – speed, action, impulse
Dagaz – renewing transforming fire
Tiewaz – starlight, heavenly fire, guiding light
Qweorth – sacred fire, holy fire, essential fire
You could also create a bindrune that combines these elements into one sigil of elemental fire that could serve as a key and gateway to connect with the power of fire through the runes, and maybe also be the sigil that is an elemental fire ally that could help you to channel, connect and work with the power of fire.