The allowable range of the mounting posture is that the upper limit is 90° (conduit 
tube port becomes horizontal) and the lower limit is 45°.
Vertical 
plane
Upper limit 90°
Lower limit 45°
Horizontal 
plane
 Side
90°
45°
  Handling Precautions
 Mount this unit at an appropriate angle so that it monitors the burner • 
from the upper slanted position.  If this unit is mounted so that it moni-
tors the burner from the lower slanted position or horizontal position, 
dust or soot may accumulate on the monitoring window or in the moni-
toring pipe.  This may block the ultraviolet rays, causing the flame not to 
be detected.
Mounting of monitoring pipe n
Materials of monitoring pipe  ●
Use a monitoring pipe with a black inside wall.  If a pipe with the stainless steel or 
galvanized inside wall is used, diffused reflection of the ultraviolet rays occurs in-
side the pipe, causing a malfunction.
Size of monitoring pipe ●
To detect the ultraviolet rays radiation of the flame at its optimal level, it is neces-
sary to widen the light receiving area of this unit.  If a recommended flame voltage 
of 2.0 V or more cannot be kept, make the monitoring pipe thicker to receive a suf-
ficient amount of ultraviolet rays.
•   Use the monitoring pipe as thick as possible and connect the pipe to this unit 
with the reducing socket.
•   Make the length of the monitoring pipe as short as possible.  However, always 
keep the operating ambient temperature within 100 °C (up to 120 °C during 
flame detection).