Maintenance Considerations For Air Bath And Airless Ovens - Siemens Maxum II Manual

3.5

Maintenance Considerations for Air Bath and Airless Ovens

The following practices must be observed in order to operate, maintain and prevent
compromise of the airbath oven (including programmed temperature oven) and airless ovens
of Maxum II. Modular ovens are described in the next section.
● It must be ensured that the analyzer T-rating is suitable for the area in which the analyzer
is to be installed. If a particular application requires oven temperatures that are very hot, it
may be necessary to locate the analyzer in a different area of the plant that has a better T-
rating. It is the responsibility of the user to ensure that the actual, final analyzer T-rating is
suitable for the area of installation. Please refer to the table at the beginning of this
document.
● Instrument air supplied to the air bath oven of the analyzer must be clean and dry as
described above. Unsuitable air may cause smoke or other damage to the analyzer and
can result in a hazardous condition.
● The set point resistors used to control the T-rating must have the correct value for the
desired T-rating. These resistors are installed at the factory and should be changed only
by properly trained service personnel. If these resistors are the wrong value, it could be
possible for temperatures within the oven to become too hot for the stated T-rating of the
analyzer.
● For the air bath oven, the heater apparatus should be inspected for physical damage. If
there are any cracks, bends or other damage, the assembly must be switched off
immediately and replaced. All fittings and conduit attachments must be tight and installed
according to local codes.
● It is possible for heater elements to burn out. The expected life of the heater element is
generally 2 years or more for isothermal applications; however, it may be shorter in
programmed temperature applications. For the air bath oven, if the heater is to be replaced,
the factory spare part is a complete sealed system. For the airless oven, it is possible to
replace only the heating element. In either case the new heater must be installed using
proper techniques as required locally to ensure that conduit fittings are tightened correctly,
that all wiring is reinstalled correctly, and that all pneumatic fittings are attached correctly.
This process should be supervised by persons knowledgeable about local electrical and
fire safety practices.
● The oven heater used within the air bath oven is a sealed and closed assembly. It cannot
be disassembled for repair in the field. If the heater element or any attached components
fail, the entire heater assembly must be replaced with a new replacement part from the
factory.
Explosion Protection Safety Standards
Manual, August 2017, A5E02220442001 Rev 8
3.5 Maintenance Considerations for Air Bath and Airless Ovens
Safety Systems - Oven
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