33
®
Installation of Oxygen Probe
Mounting the oxygen probe
The probe must be mounted in a manner which ensures that the flue gases pass into the gas tube at its
open end and out of the tube at the flange end. Furthermore, if possible, the flange should be vertical
with the gas tube angled downwards to ensure that particulates do not build up within the sample
tube. Probe mounting with the flange horizontal is acceptable. Inverted probe mounting is not
acceptable.
There are two types of flange available (see the drawing on next page). With either flange the verti-
cal centre line of the flange shown on the drawing should correspond to the gas flow direction.
6 stainless steel M6 x 20mm socket cap screws are provided for probe attachment.
The probe flange temperature must be maintained at the temperature of the flue wall by repacking or
adding lagging which may have been removed to mount the probe. Sulfate condensation will occur if
the flue wall of an oil fired boiler falls below approximately 130°C. The sulfate problem does not
occur in gas fired installations, but vapor may cause problems due to condensation if the temperature
of the flue gas falls below 100°C.
The maximum flue gas temperature is 540ºC.
FLUE
GAS
GAS
FLUE
FLUE
GAS
GAS
FLUE
GAS
FLUE
FLUE
GAS
GAS
FLUE
30
VERTICAL FLUE
PROBE MOUNTED ON SIDE
PREFERRED MOUNTING
1
PROBE MOUNT HOLES SHOWN
(SEE HG220371)
NOTE ORIENTATION RELATIVE
TO FLUE GAS FLOW.
C
C
SECTION ON C-C
D
D
SECTION
ON D-D.
SIDE VIEW
UNACCEPTABLE MOUNTING
HORIZONTAL FLUE
PROBE MOUNTED UNDERNEATH.
4
DO NOT FIT PROBE IN
THIS POSITION.
TOP VIEW
SECTION ON A-A.
B
B
A
A
3
PROBE MOUNTED ON TOP.
HORIZONTAL FLUE
NON-PREFERRED MOUNTING
SECTION ON B-B
SIDE VIEW.
2
ACCEPTABLE MOUNTING
HORIZONTAL FLUE
PROBE MOUNTED ON SIDE.
F
F
E
E
SIDE VIEW
SECTION ON F-F.
TOP VIEW
SECTION ON E-E.
PROBE MOUNT HOLES SHOWN
(SEE HG220371). HOLE ORIENTATION
RELATIVE TO FLUE GAS FLOW.
PROBE MOUNT HOLES(SEE HG220371)
NOTE ORIENTATION RELATIVE TO
FLUE GAS FLOW.
