Installation; Overview; Sensing Unit Requirements And Location - Honeywell 7866 Operation And Maintenance Manual

3.1

Overview

This section describes the installation requirements and procedures for the 7866 Triple Range Digital
Analyzer/Indicator.
3.2

Sensing Unit Requirements and Location

Location
Locate the sensing unit as close as possible to the sampling probe to minimize response lag. This should be
at a point in the gas stream which best represents the true gas composition. An ac power line is not
required. The sensing unit can be located in a protected outdoor area. The housing is watertight; but it
should not be exposed to direct rays from the sun. Ambient temperature must not go above 50 °C (122 °F)
or below –10°C (14 °F).
Connections
Provide a three-conductor copper-wire cable (four-conductor if a solenoid calibrate valve is used) to
provide the connections between the sensing unit and the 7866 Digital Controller. Connecting
cable/conductors must be rated at 90ºC. The required wire size for each conductor is listed in Section 3.7
according to cable length. An adapter is supplied to terminate 1/2 inch threaded conduit and connect to the
sensing unit's watertight housing. The explosion-proof housing is tapped for 1/2 NPT conduit.
Clearance
Provide at least 12 inches clearance above the top of the sensing unit to allow the internal assembly to be
removed for servicing. Allow appropriate space below the sensing unit for 1/4 inch or 6 mm inlet and
outlet tubing connections. Position the sensing unit on a vertical surface with the inlet and outlet fittings at
the bottom. Allow space at the right-hand opening for the solenoid calibrate valve, which, if supplied, is to
be mounted here.
Sampling System
Provide a sampling system to deliver a clean and relatively dry sample at a rate of 100 to 2000 cc per
minute. The sample should be free of dust.
Calibrating Gases
Provide a source of calibrating gases; e.g., cylinders of compressed zero gas and span gas with pressure
regulating valves on each. In general, a zero gas contains all gas components in the sample stream except
the measured gas. For suppressed-zero ranges, zero gas contains measured gas at or slightly above the low-
end value. Concentrations should be those normally present in the stream. A span gas contains all of the
gases in the sample stream at expected concentrations with measured gas concentration accurately
analyzed. Concentration of water (vapor) in the calibrating gas should be the same as that in the
background gas. Therefore, a gas saturator or dryer may be required.
9/06 7866 Triple Range Digital H

3. Installation

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Installation
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