Product Overview

The Honeywell 2108D0258 Searchpoint Optima Plus Gassing Cover is a dedicated gas testing accessory for the Searchpoint Optima Plus infrared point gas detector. It provides a controlled way to introduce test gas to the detector during field functional checks, allowing maintenance personnel to verify that the detector responds to the target gas under actual installation conditions.

Unlike the Calibration Cap, which is intended for accurate detector calibration, the Gassing Cover is primarily used for routine functional testing. It fits over the detector’s standard weather protection and covers the gas inlet slots. Test gas is introduced through the injection tube on the cover, allowing it to reach the detector’s measurement chamber.

This arrangement is particularly useful in industrial facilities where fixed infrared gas detectors operate continuously and need periodic response verification. Examples include oil and gas processing plants, refineries, chemical production facilities, compressor stations, and offshore installations.

During a functional gas test, a technician installs the 2108D0258 over the detector’s existing weather protection and introduces an appropriate test gas through the injection connection. The gas passes through the weather protection and dust barrier before reaching the measurement chamber. The detector’s response can then be checked against the expected reading for the applied gas concentration.

The Gassing Cover is especially useful because it allows testing without removing the standard weather protection. This reduces the amount of disassembly required during routine maintenance and makes field testing more convenient for detectors installed in exposed or difficult-to-access locations.

An important distinction is that a functional response check does not automatically constitute an accurate calibration. The Searchpoint Optima Plus uses infrared absorption technology and has a dedicated calibration procedure. When accurate calibration is required, the 2108B0272 Calibration Cap should be used instead.

The 2108D0258 is a temporary maintenance accessory. It must be removed immediately after testing because leaving it fitted can prevent ambient gas from reaching the detector’s measurement chamber. Once the test is complete, the detector must be allowed to clear the introduced gas and return to its normal monitoring condition.

For maintenance teams working with Searchpoint Optima Plus installations, the 2108D0258 provides a practical solution for applying test gas and checking detector response without dismantling the standard weather protection assembly.

Technical Specifications

Product Features

• Dedicated Gas Testing Accessory: Developed for field testing of Searchpoint Optima Plus infrared gas detectors.
• Controlled Test Gas Introduction: Uses an injection tube to introduce test gas into the detector’s weather protection.
• Standard Weather Protection Compatibility: Fits over the existing weather protection without requiring its removal.
• Measurement Chamber Gas Access: Allows introduced gas to diffuse through the dust barrier into the detector’s measurement chamber.
• Functional Response Verification: Supports checks of the detector’s response to an appropriate known test gas concentration.
• Convenient Field Maintenance: Reduces the need to dismantle the detector’s standard protective accessories during routine testing.
• Temporary Installation: Designed to be removed after the gas testing procedure.
• Searchpoint Optima Plus Compatibility: Intended for the corresponding Honeywell infrared point gas detector.

Working Principle

The 2108D0258 works by directing test gas into the weather protection surrounding the Searchpoint Optima Plus detector. The gas then diffuses through the dust barrier and reaches the internal measurement chamber, where the infrared sensing system detects the target gas.

The basic testing arrangement follows this sequence:

Test Gas Supply → Injection Tube → 2108D0258 Gassing Cover → Standard Weather Protection → Dust Barrier → Measurement Chamber

Fitting the Gassing Cover

The technician first checks that the Searchpoint Optima Plus detector is in a suitable condition for functional testing.

The 2108D0258 is then fitted over the detector’s standard weather protection. Unlike the Calibration Cap, it does not require the standard weather protection to be removed.

The cover is positioned so that its injection tube can deliver test gas into the designated area surrounding the detector’s gas inlet slots.

Introducing Test Gas

An appropriate test gas is connected to the injection tube. According to the Searchpoint Optima Plus operating instructions, a typical functional response check uses a gas flow rate of approximately 1–1.5 litres per minute for around 30–60 seconds.

The introduced gas enters the weather protection and diffuses through the dust barrier into the measurement chamber.

This arrangement exposes the detector to the test gas while maintaining the normal protective components in position.

Infrared Gas Detection

The Searchpoint Optima Plus uses infrared absorption technology to detect combustible hydrocarbon gases.

When the test gas reaches the measurement chamber, it interacts with the detector’s infrared measurement system. The detector evaluates the resulting absorption characteristics and generates a corresponding gas concentration reading.

The technician compares the displayed or transmitted reading with the expected response for the selected test gas.

For the functional response check described in the operating instructions, the reading should generally be within ±20% of the target value. The actual assessment must also account for the test gas concentration, its tolerance, atmospheric pressure, ambient temperature, and wind conditions.

Verifying Detector Response

The Gassing Cover allows the technician to check whether the detector responds appropriately when exposed to the introduced gas.

If the response is outside the acceptable range, the technician should review the test gas concentration, gas delivery arrangement, and detector zero condition before deciding whether further adjustment is necessary.

The cover itself does not perform calibration or modify the detector’s internal measurement settings.

Removing the Gassing Cover

After testing, the gas supply is disconnected and the 2108D0258 is removed.

The technician should allow the introduced test gas to clear, typically around 30 seconds under the procedure described in the operating instructions, and confirm that the detector reading has returned to its normal baseline.

Removing the cover is essential because it restores unrestricted access to ambient gas for normal monitoring.

Functional Testing Versus Calibration

The 2108D0258 and 2108B0272 serve different maintenance purposes.

The Gassing Cover is used for field functional checks and fits over the standard weather protection. The Calibration Cap is used when accurate calibration is required and has a different installation arrangement.

Using the appropriate accessory prevents a routine gas response test from being mistaken for a calibration procedure.

Role in the Searchpoint Optima Plus Gas Detection System

The Honeywell 2108D0258 functions as a temporary testing accessory within the Searchpoint Optima Plus fixed gas detection arrangement. It provides the interface between the test gas supply and the detector’s existing protective assembly.

A typical field testing sequence follows this structure:

Searchpoint Optima Plus Detector → Standard Weather Protection → 2108D0258 Gassing Cover → Test Gas Supply → Detector Response Verification

In a typical refinery installation, Searchpoint Optima Plus detectors are positioned around pumps, compressors, pipework, and other locations where hydrocarbon leakage may occur.

During scheduled maintenance, technicians can use the 2108D0258 to introduce test gas directly to each detector. The resulting response is checked through the detector interface or connected monitoring system.

This allows the maintenance team to verify detector operation without removing the standard weather protection assembly.

After testing, the cover is removed and the detector returns to its normal gas monitoring arrangement.

Industrial Applications

Installation and Maintenance

1. Verify Accessory Compatibility: Confirm that Honeywell 2108D0258 is the correct Gassing Cover for the installed Searchpoint Optima Plus detector.
2. Review the Testing Procedure: Check the detector operating instructions and identify the appropriate test gas, target concentration, and required testing conditions.
3. Prepare the Work Area: Follow the facility’s permit-to-work and gas testing procedures. Account for potential alarm activation and ensure the appropriate control system arrangements are in place.
4. Inspect the Gassing Cover: Examine the housing, injection tube, gas connection, and contact surfaces for damage or contamination.
5. Check the Detector: Inspect the Searchpoint Optima Plus housing and standard weather protection before fitting the accessory.
6. Fit the Gassing Cover: Position the 2108D0258 over the standard weather protection, ensuring that it is correctly seated and that the injection tube is accessible.
7. Connect the Test Gas Supply: Connect the appropriate test gas cylinder and flow regulator to the injection tube using suitable tubing.
8. Set the Gas Flow Rate: Adjust the delivery rate according to the detector operating procedure. A typical functional response test uses approximately 1–1.5 litres per minute for 30–60 seconds.
9. Introduce the Test Gas: Apply the selected gas and allow it to diffuse through the weather protection and dust barrier into the measurement chamber.
10. Verify Detector Response: Check the detector reading against the expected target response. Investigate abnormal readings before returning the detector to normal service.
11. Remove the Gassing Cover: Disconnect the gas supply and remove the 2108D0258 after testing. Allow the test gas to clear and verify that the detector reading returns to its normal baseline.
12. Restore Normal Operation: Confirm that the detector is no longer in an inhibited or maintenance condition, restore any isolated alarm circuits, and document the test results.

Compatible System Components

Recommended Related Models

Key Advantages

• Provides a convenient method for introducing test gas during field functional checks.
• Fits over the detector’s standard weather protection.
• Allows test gas to diffuse through the dust barrier into the measurement chamber.
• Supports functional response verification without dismantling the protective assembly.
• Uses an injection tube for controlled test gas delivery.
• Supports routine maintenance of fixed infrared gas detection installations.
• Can be removed immediately after testing to restore normal detector operation.

Technical FAQs

What is the main purpose of the Honeywell 2108D0258?

The 2108D0258 is used to introduce test gas to Searchpoint Optima Plus detectors during field functional checks. It allows technicians to verify the detector’s response to an appropriate test gas without removing the standard weather protection.

Does the Gassing Cover need to replace the standard weather protection?

No. The 2108D0258 fits over the existing standard weather protection. Test gas enters through the injection tube and diffuses through the protective assembly into the detector’s measurement chamber.

What gas flow rate should be used during a functional response test?

The Searchpoint Optima Plus operating instructions describe a typical test using an appropriate gas flow rate of approximately 1–1.5 litres per minute for 30–60 seconds. The detector response should generally be within ±20% of the target reading, subject to the test gas and environmental conditions.

Can the 2108D0258 be used instead of the 2108B0272 Calibration Cap?

No. Although both accessories introduce gas to the detector, they have different purposes and installation arrangements. The 2108D0258 is intended for field functional checking and fits over standard weather protection. The 2108B0272 is the dedicated accessory for accurate calibration and requires removal of all weather protection except the dust barrier.