Rev. 8 reflects the following:
Changes to: Table D on page 9, Figs 11-12 on page 15, Table I and text changers on page 20, Fig. 18 on page 21, Fig. 21 on page 22, Figs. 22-28 on pages 25-30, Table N on page 28, Modes 1,4, 6 and 8 on pages 30-32, Heater Sequence of Operation section on page 36, UDB Diagnostic Board section on page 38, wiring diagrams on pages 39 and 40, UDB Fault History section on page 48.
Additions: Fig. 2 on page 6, Low-lead requirement on page 5, Fig. 8 on page 11, Caution on page 20, Fig. 22 on page 22, Fig. 35 on page 32, note on page 38, Filter Maintenance and Filter Replacement instructions (including Figs. 48 and 49) on page 50.
