Honeywell 69-1490 Owner's Manual page 5

Em Ht and Aux Ht Indications
Emergency Heat (Em Ht) and Auxiliary Heat (Aux Ht)
indications are not available on all models. The
points to either Em Ht or Aux Ht when these modes are
active.
Em Ht: The
SYSTEM switch is set at Em Ht.
Aux Ht: The
living space needs auxiliary backup heat to help
handle the heating load.
indicator points to Em Ht when the
indicator points to Aux Ht when the
INDICATOR
Em Ht
Room
Set
M18425
5
indicator
69-1490