Agilent Technologies 6890 Series, Service Manual, Page: 412 / 867

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Jun 2001
Mainframe
Agilent 6890 Gas Chromatograph Service Manual
420 Oven and Temperature Control
Heated zones
In addition to the oven, the 6890 GC has six small heated zones. To reduce
the chance of hazardous electrical shocks, all are powered with 40 volt full
wave rectified current instead of 120 volt AC. A total of 440 watts is available
for the zones. This accommodates six 70 watt heaters. It is also possible to
have up to two 150 watt heaters. Adding a 150 watt heater reduces the
maximum number of heaters by one.
These further wattage restrictions/rules apply:
• Six 70 watt heaters are allowed.
• Any combination of heaters < 225 watts per chromatographic channel
(i.e., Front Inj., Front Det., and Aux 1 OR Back Inj., Back Det., and Aux 2).
• Any single zone can be 150 watts or less.
The 6890 GC will not allow configurations over 440 watts to operate. The
detector zones can only be temperature programmed from a ChemStation.
There are two auxiliary zones (Aux 1 and 2) and each supports three
temperature ramps. There is no cooling provided for ramped zones except the
oven and cool on-column inlet.
Oven ramp rates
To use the fast oven ramp rates (a 240 V power option is required), your
electric service must be able to supply
≥
200V at
≥
15 Amp.
The highest rate that you can achieve depends on many factors, including the
room temperature, temperatures of the inlets and detectors, the amount of
material inside the oven (columns, valves, etc.), and whether or not this is
Heaters allowed
70 Watt 150 Watt
5–6 –
3–4 1
1–2 2