A.O. Smith 120 through 250 Series - Manual (Page 53)

Instruction manual BFC 53
gis
8.4 Service condition
The figure shows the message
SERVICE REQUIRED .Should this message appear,
then the appliance is in need of a service and
maintenance inspection. In that case, contact your
service and maintenance engineer.
Note
The message SERVICE REQUIREDis based on
the number of expired burning hours and the preset
service interval. Should the service interval have been
incorrectly selected, contact the service and
maintenance engineer for instructions on how to
adjust this. Information on the maintenance frequency
is provided elsewhere in the
manual
(14 "Maintenance frequency") .
!!! WARNING !!!
MAX. BURNING HOURS:
SERVICE REQUIRED