6.—(1) An oil heater shall be of good construction, sound materials and adequate strength.
(2) No part of an oil heater in which a crack or distortion might affect its proper working shall be made of drawn brass unless any stress caused by the process of drawing and capable of causing such a crack or distortion is eliminated.
(3) If it is necessary for its safe operation that it should be levelled, an oil heater shall include a device for levelling it.