Casella CEL Airborne particulate monitoring system - Manual (Page 7)

HB3256-03 Page 5
The frame footprint drawing indicates the approximate position of fixing holes. It is suggested
that as a more accurate method the actual frame base should be used as a template when drilling
the mounting holes in the site location.
Wall mounted systems.
For wall mounted applications which will be attached to the inside of a case or shed etc., please
refer to the wall mounted drawings.
It should be noted in particular when choosing a suitable enclosure for mounting of the APM950
that a sloping roof enclosure is not desirable as this will cause variations in the wind dependant
upon the slope of the roof and the direction of the wind.
The APM950 can be supplied with two cross arms for wall mounting the enclosure as shown in
the installation drawings section. These cross arms are attached to APM950 enclosure and then,
using either the pre-drilled holes or holes drilled to your own requirements, the APM950 can be
mounted to the wall of the outer enclosure.
Alternatively, if convenient, the enclosure can be mounted straight on to the wall by using the
mounting brackets of the case. The dimensions of which are shown within the installation
drawings section. It may be wise to use the actual case and brackets as a template to drill the
holes in the wall. Again consideration must be given to the wall material, thickness etc. when
attaching the system to a wall/shed etc.
If this option is undertaken then a hole will need to be placed in the roof of your enclosure for
fitting of the Anderson head. (see the installations drawing section).
Size Selective Head.
The system is supplied with the head separate. Before assembly check that O-ring 0/026/1 is in
place on the support tube and that the threads have a film of silicone grease. Failure to maintain
an adequate seal may result in air leakage and water ingress.
The assembly is attached simply by removing the transit cap from the support tube flange on the
enclosure and mounting the support tube assembly as shown in the installation drawings section.
The probe inlet collar is then tightened. The moisture jar is assembled to the Anderson head, and
the whole assembly placed onto the support tube as shown.
Roof Inlet.
It is important to maintain a reliable water tight seal between the sample inlet tube and the roof
structure. Failure to maintain a seal will result in water flowing down the inlet tube and into the
building.