(a) Ensure ventilation of the preheater when the induction air preheater is not being used during engine operation;
(b) Allow inspection of the exhaust manifold parts that it surrounds; and
(c) Allow inspection of critical parts of the preheater itself.
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23–43, 58 FR 18974, Apr. 9, 1993]