Orange arrow
points at the primary thermal sensor.
Blue arrow
points at the shaft spring. Note pin on far right of spring. It can be used to hold the spring
in place after disconnecting and sliding spring onto the shaft.
WARNING!
USE CAUTION!
SPRING IS UNDER HIGH TORSION AND MAY CAUSE SERIOUS INJURY!
WRONG
The original motor was a
Phillips P150. A Siebe
MA418 was used to replace
it. The shaft spring was not
disconnected. The MA418
failed due to high holding
torque load against its own
internal spring and the
external shaft spring.
Note on sensor wiring.
When a number of damper sections
are used and multiple motors drive the
sections, only one fire sensor is
allowed. All sections of the damper
assembly must close together. The
sensor above is the only one for
several sections.
The motor at the right does not have a
separate sensor. It is wired to the
single sensor shown in the top picture.
Ruskin Phillips P150 to Belimo FSNF or FSAF March 2018
7
