The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
27. For the same reasons (the Vaisvânara) cannot be the divinity (of fire), or the element (of fire).
The averment that the fanciful attribution of members contained in the passage 'His head is Sutegas,' &c. may apply to the elemental fire also which from the mantras is seen to be connected with the heavenly world, &c., or else to the divinity whose body is fire, on account of its power, is refuted by the following remark: For the reasons
already stated Vaisvânara is neither the divinity nor the element. For to the elemental fire which is mere heat and light the heavenly world and so on cannot properly be ascribed as head and so on, because an effect cannot be the Self of another effect.--Again, the heavenly world cannot be ascribed as head, &c. to the divinity of fire, in spite of the power of the latter; for, on the one hand, it is not a cause (but a mere effect), and on the other hand its power depends on the highest Lord. Against all these interpretations there lies moreover the objection founded on the inapplicability of the term 'Self.'