Effect of boost control cutout prior to +12 psi boost modifications

[41Sqn_Banks]

AP 1590B Merlin II and III Aero-Engines

In its unmodified condition, the boost control cut-out valve permitted the boost pressure to rise very considerably. Mod. Merlin 154, however, limits the pressure to +12 lb. per sq. in. for use under emergency condition (see para. 359A et seq.).