Honeywell 2108N4000H Combustible Gas Detector

Honeywell Searchpoint Optima Plus (2108N4000H) Falta & Warning Troubleshooting Table

Reading methods: CERVO 475/375 Communicator, SHC1 Handheld Interrogator, EDD Device Description File; W=Warning, F=Fault. Under fault condition, output defaults to 0mA (this HART version can be set to 1mA). Some faults are latched and require manual clearing or power cycle reset.

Error Code	Status	English Name	Descrição da falha	On-site Troubleshooting Steps	Latched
0	C / F	Temperature Limit Exceeded	Operating temperature near or out of -40~+65℃ range	1. Measure ambient temperature of the detector	Não
				2. Check direct sunlight or overheating from heat tracing
				3. Melhorar a ventilação & shading; relocate if over-temperature
4	C / F	Bad 24V Supply	Supply voltage outside 18～32VDC operating range	1. Measure terminal voltage under load (not no-load power supply)	Não
				2. Verifique a queda de tensão do cabo, short circuit and wire gauge
				3. Verify power capacity and restart the loop
5	C / F	Bad 4-20mA Loop	Analogue output deviation >0.5mA, cannot output correct signal	1. Verifique a polaridade, shielding grounding and loop resistance	✅ Latched
				2. Avoid hot-plugging multimeter probes
				3. Ciclo de energia; if fault remains, output circuit is damaged
6	C / F	Negative Gas Reading	Negative zero drift of gas reading	1. Confirm clean atmosphere with no hydrocarbon gas	Não
				2. Remove dust filter and clean optical window
				3. Perform zero calibration; eliminate condensation and solvent interference
8	C / F	Obscured Optics (Optical Contamination)	Lente & gas chamber blocked by oil, dust or water vapour, optical path attenuation	1. Remove weather shield and dust barrier	Não (frequent warning)
				2. Wipe optical window with lens paper and anhydrous ethanol
				3. Dry and reset; check heating function if heavy condensation
11	C / F	Low Lamp Output	Infrared lamp power degraded, end-of-life aging	1. Clean optics first to rule out contamination	Não
				2. If alarm persists after reset: replace optical module due to lamp failure
13	F	Hardware Fault	Self-test failure of main board and drive circuit	1. Power off for 5 minutes then re-power	✅ Latched
				2. Estabilizar a fonte de alimentação
				3. Recurring fault: return for repair or replace transmitter
16	F	Poor Signal Quality	Noisy, unstable infrared signal with low SNR	1. Clean optical window and filter first	✅ Latched
				2. Check water ingress or frost inside gas chamber
				3. Replace optical assembly if lamp aging or optical offset occurs
22	C / F	Internal Firmware Failure	Firmware checksum error, memory exception	1. Full power cycle restart	✅ Latched
				2. Clear fault log via HART tool
				3. Persistent error: re-flash firmware or replace main board

📌 Common General Faults (No independent Error ID in HART)

HART Communication Failure

Verificar: 250Ω HART resistor must be installed on the loop; correct polarity; single-end shield grounding; no excessive non-HART devices on the bus; matching baud rate.

Slow reading drift with no error code

Verificar: overdue calibration; clogged dust filter; continuous low-level hydrocarbon interference; heavy oil adsorption inside gas cell.

No current output & no communication after power-on

Verificar: water ingress & terminal corrosion in M25 junction box; burnt circuit due to reverse polarity; fusível interno queimado.

🛠️ Operation Guidelines (for 2108N4000H)

Clear Latched Faults: HART menu →【Fault/Warning】→Clear; or power off ≥30 seconds then restart. Hardware faults will reoccur immediately after reset; do not mask them permanently.
Calibration Precondition: Clear all optical path & lamp warnings before zero/span calibration; calibration will drift severely with active optics contamination warning.
Spare Parts Division: Erro 8,11,16 = optical module (lamp + detector + lens); Error5,13,22 = main board failure. Board-level repair is not recommended; replace the whole transmitter directly.
SIL2 Reminder: F-class faults trigger SIL safety loop action. Do not run the detector with fault masked for long; rectify promptly.

(Searchpoint Optima Plus)

Product Position: Point-type NDIR hydrocarbon combustible gas detector, HART protocol version

Manufactured by Honeywell Analytics UK. NDIR infrared principle, immune to catalytic bead poisoning. Ideal for offshore platforms, refineries, LNG and other harsh environments; Nível de integridade de segurança SIL2.

✅ Model Coding Definition

2108: Searchpoint Optima Plus series

N: Hydrocarbon HC version (metano, propane, gasoline etc., seu modelo)

4: Standard diffusion type with weather shield

000: Without remote gas cell & sampling path

H: CERVO 7 protocol superimposed on 4-20mA signal (suffix N = pure 4-20mA without HART, por exemplo. 2108N4100N)

Fio: M25 (distinguished from 41xx series with 3/4″Rosca NPT)

Configuração padrão: 316L electropolished stainless steel housing, dust filter, nylon weatherproof cover, sunshade against rain splash.

📌 Key Technical Specifications

Item	Parâmetro
Princípio de detecção	Non-Dispersive Infrared (NDIR)
Faixa de medição	0～100%LEL; configurable for hundreds of hydrocarbons & solvents (metano, propane, ethylene, gasoline, aromatics)
Fonte de energia	DC18～32V, nominal 24VDC; max power consumption ＜4.5W
Saída de sinal	4-20mA + HART7; Modbus RS485 multi-drop bus available with optional DX100(M) módulo
Current Levels (Fault/Inhibit/Alarm)	Falta: 0mA (HART version configurable to 1mA); Inhibit: default 2mA; Aviso: default 3mA; Over-range: 20~21.5mA (default 21mA)
Tempo de resposta (Methane)	T50＜3s, T90＜4s
Temperatura operacional	-40℃ ~ +65 ℃
Proteção de entrada	IP66 / IP67
Material da Habitação	316 Aço inoxidável (CF8M); peso total aprox.. 1.6kg
Certificações de segurança	ATEX, IECEx, FM, CSA; SIL2 (CEI61508)
Precisão	Baseline drift ＜±1%FSD (HC); ＜±2%FSD (ethylene)
Pressure Effect	0.1% reading per mbar

✨ Infrared vs Catalytic Bead Advantages

Resistant to catalytic poisons (silicone, lead, H₂S), longer service life and extended maintenance interval
Fail-safe optical self-test; no silent failure risk
Works normally in inert atmosphere (catalytic sensors require oxygen)
Built-in temperature control heating; anti-condensation optical window; pre-warning for lens contamination
Onboard event log; support HART communicator for commissioning, calibration and diagnostics

🧾 Typical Application Scenarios

Offshore oil & gas platforms, FPSO, oil tankers, refineries, LNG/LPG filling stations, gas regulator stations, gas turbine power plants, solvent coating & printing workshops, tank farms.

📎 Cross-model Reference (for replacement & seleção)

2108N4000H: M25 thread, CERVO, diffusion type with weather shield (your unit)

2108N4100N: 3/4″TNP, pure 4-20mA, no HART

2108N4100H: 3/4″TNP, Versão HART

2108N5100H: Flow-through sampling type with HART, for pipeline sampling systems

⚠️ Notas importantes

Infrared detector only responds to hydrocarbons; cannot detect non-hydrocarbon flammable gases such as H₂, CO, NH₃.
Calibration gas must match target gas; response factor varies for different hydrocarbons.
Cannot directly replace catalytic bead sensors without rechecking host logic and alarm thresholds.
Consumable spare parts: optical module, dust filter and weather shield are regular wear items.

Honeywell Searchpoint Optima Plus (2108 Série) Lista completa de modelos

Regras de codificação de modelo

2108N: Standard Hydrocarbon (HC) versão (metano, propane, gasoline etc.)

2108B: Ethylene & solvent dedicated version (ethylene, aromatics, esters)

4o dígito: 4 = Diffusion type; 5 = Flow-through sampling type (with gas cell)

Thread code: 0 = M25; 1 = 3/4″TNP

Sufixo: N = 4-20mA only; H = 4-20mA + HART7 protocol

Sufixo 10 = with Remote Gas Cell (RGC); 00 = without remote gas cell

2108N Hydrocarbon Standard Models (Série Principal, including 2108N4000H)

2.1 M25 thread (0) | Diffusion (4) | No RGC (00)

2108N4000N: 4-20mA, M25, diffusion, weather shield
2108N4000H: 4-20mA+HART, M25, diffusion (seu modelo)
2108N4001N: Ethylene calibrated, M25, diffusion, 4-20mA
2108N4001H: Ethylene calibrated, M25, diffusion, CERVO
2108N4010N: HC + RGC remote test cell, M25, diffusion
2108N4010H: HC + RGC, M25, diffusion, CERVO

2.2 3/4″Rosca NPT (1) | Diffusion (4) | No RGC (00)

2108N4100N: 4-20mA, TNP, diffusion
2108N4100H: 4-20mA+HART, TNP, diffusion
2108N4110N: With RGC, TNP, diffusion
2108N4110H: With RGC, TNP, diffusion + CERVO

2.3 Flow-through sampling type (5) for sampling pipeline & pre-treatment systems

M25 thread (0)

2108N5000N: Flow gas cell, M25, 4-20mA
2108N5000H: Flow gas cell, M25, CERVO
2108N5010N: Flow type + RGC, M25
2108N5010H: Flow type + RGC, M25 + CERVO

3/4″Rosca NPT (1)

2108N5100N: Flow gas cell, TNP, 4-20mA
2108N5100H: Flow gas cell, TNP, CERVO
2108N5110N: Flow type + RGC, TNP, high concentration range (0~100%vol CH₄)
2108N5110H: Flow type + RGC, TNP + CERVO

2.4 Special XTC Marine & Multi-certified Models (44/46/48 série)

2108N4400N / H: Diffusion, marine certification, M25
2108N4600N / H: Diffusion, UL/FM certified, M25
2108N4601N / H: Ethylene calibrated, 46-type diffusion
2108N4800N / H: Optima Plus XTC version, M25 diffusion
2108N5400/5600/5800 N/H: Corresponding flow-through versions (44/46/48 sampling models)
2108B Ethylene & Solvent Dedicated Models (for Optima X/Z sampling systems)

Diffusion type (4)

2108B4001N / H: Ethylene calibrated, M25 diffusion
2108B4101N / H: Ethylene calibrated, NPT diffusion

Flow-through sampling type (5, only for sampling systems)

2108B5001N / H: Ethylene flow cell, M25
2108B5101N / H: Ethylene flow cell, TNP
2108B2001N / H: Optima X fast-response sampling model (special gas cell)
2108B2051N: DNV marine certified version
Full Series Spare Part Order Codes
Optical Module: 2108D3001 (Methane), 2108D3034 (Ethylene)
Remote Gas Cell (RGC): 2108B0240
Flow-through Gas Cell Assembly: 2108B0282
Dust Filter + Weather Shield: 2108B2337
terminal & Junction Box: 2108B2360
Tabela de seleção rápida (for replacement)

Tipo de montagem	Fio	Without RGC (Padrão)	With RGC (Remote Test)
Wall-mounted Diffusion	M25	2108N4000N / H	2108N4010N / H
Wall-mounted Diffusion	3/4″TNP	2108N4100N / H	2108N4110N / H
Pipeline Sampling	M25	2108N5000N / H	2108N5010N / H
Pipeline Sampling	3/4″TNP	2108N5100N / H	2108N5110N / H

Observações Suplementares
N = 4-20mA analogue only; H = HART enabled. Do not mix loop types; 250Ω resistor is mandatory for HART loops.
2108N only detects hydrocarbons; 2108B is dedicated for ethylene, esters and alcohols. Neither can detect H₂, CO or NH₃.
All models meet SIL2, ATEX/IECEx/FM certification; Proteção de entrada IP67.