TOCA TS-303 Combustible Gas Alarm – Fixed Gas Detector (LEL=100) by Toka Seiki

Product Information

Manufacturer / Brand	TOCA – Toka Seiki Co., Ltd. (Japan) (also listed as Tohke Seiki / Q-con Corp.)
Model	TS-303
Product Type	Combustible Gas Alarm – single-point fixed gas detector / alarm unit
Measuring Range	0 – 100% LEL (meter marked LEL=100)
Front Indicators	POWER lamp, ALARM lamp, TROUBLE indication, analog LEL meter
Front Buttons	RESET (復帰) and DIMM. (減光 – dimmer)
Installed Locations (labels on supplied units)	Pump Room (Fixed Gas Detector), Air Condition Room, Engine Room No. 2, Port Passage, Cabin Passage
Serial Numbers (from calibration labels)	174030, 172541, 126275, 18609, 12854 (one digit on some labels is not fully clear)
Previous Calibration Labels	Umbrella Calibration Co. Ltd – Cal 18 Sep 25, Due 18 Sep 26 (recalibration status to be confirmed)
Power Rating	Not clearly visible in the supplied photograph
Country of Manufacture	Not clearly visible in the supplied photograph (manufacturer is Japanese)
Condition	Refurbished (subject to confirmation)
Supplier	SM MARINE SERVICE™, Chattogram, Bangladesh

Product Introduction

The TOCA TS-303 is a Japanese combustible gas alarm made by Toka Seiki. It is a single-point fixed gas detector that continuously monitors flammable gas (such as LPG, propane, butane and methane) in 0–100% LEL and gives a local alarm. On ships it is installed in pump rooms, engine rooms, air-condition rooms and accommodation passages.

SM MARINE SERVICE™ (https://www.smmarineservice.com/) supplies TOCA TS-303 gas alarms, gas detector spare parts and marine safety equipment to ship owners and ship managers worldwide.

What Is This Equipment?

The TS-303 belongs to the Toka Seiki 303 series of one-point stationary gas alarms (the series also includes oxygen and toxic gas versions). It uses the catalytic combustion detection principle and shows the gas concentration on an analog meter scaled 0–100% LEL with green, yellow and red zones.

The front panel has a POWER lamp (green), ALARM lamp (red) and TROUBLE indication, with RESET and DIMM. (dimmer) buttons. Three cable glands on the bottom are used for power, detector head and alarm output cables. A detector head (diffusion or suction type) is connected to the unit.

The supplied set includes five TS-303 units with location labels: Pump Room, Air Condition Room, Engine Room No. 2, Port Passage and Cabin Passage. Two units have a coloured (yellow / orange) meter face.

Main Features

• Continuous combustible gas monitoring, 0–100% LEL
• Catalytic combustion type detection
• Analog LEL meter with coloured scale
• POWER, ALARM and TROUBLE indication
• RESET and DIMM. (dimmer) push buttons
• Adjustable alarm setpoint (1/10 of full scale or more)
• Volt-free 1c alarm contact output
• Resin, drip-proof enclosure with cable glands
• Can be combined for multi-point installations

TOCA TS-303 combustible gas alarm (Toka Seiki) – supplied by SM MARINE SERVICE™

Main Technical Specifications

Model	TS-303
Detection Principle	Catalytic combustion
Target Gases	LPG, butane, propane, methane and other combustible gases
Range	0 – 100% LEL
Indication Accuracy	Within ±5% of full scale
Response Time	Within 30 seconds (at 1.6 x alarm setting concentration)
Alarm Setting	1/10 of full scale or more, adjustable; alarm accuracy ±25% of setting
Alarm Contact	Volt-free 1c contact, AC125V 1A
Power Supply	AC100V 50/60Hz; DC12V and DC24V versions available
Operating Conditions	-10 to 50 °C, 95% RH or less
Detector Head	Diffusion type DZF(3) / suction type DZP (as listed by suppliers – Not verified)
Options	Recorder output, two-stage alarm, second contact output
Weight	Approx. 550 – 750 g (reported)

Inside the Unit: PCBs, Modules & Part Numbers

Toka Seiki does not publish PCB numbers for the TS-303, and no PCB labels are visible in the supplied photographs. The modules below are the functional blocks of the unit; board numbers are Not verified. Send us a photo of the PCB label for exact matching.

Main Control / Amplifier Board

Supplies the detector head bridge circuit, amplifies the sensor signal and drives the LEL meter and alarm comparator. PCB number: Not verified.

Power Supply Board

Converts the ship's supply (AC100V, DC12V or DC24V version) for the electronics and the detector head. PCB number: Not verified.

Alarm Relay & Indication Board

POWER / ALARM / TROUBLE lamps, RESET and DIMM. buttons and the 1c alarm relay output. PCB number: Not verified.

Analog LEL Indicator Meter

0–100% LEL panel meter with coloured scale. Part number: Not clearly visible in the supplied photograph.

Detector Head

Catalytic combustion detector head – diffusion type DZF(3) or suction type DZP (as listed by suppliers; Not verified).

Main Components & Related Units

• TS-303 alarm unit – main indicator and alarm unit
• DZF(3) diffusion detector head – Not verified
• DZP suction detector head – Not verified
• Toka Seiki 303 series – oxygen and toxic gas versions of the same series
• Ship alarm / monitoring system – receives the TS-303 alarm contact

Marine & Industrial Applications

• Cargo pump rooms on tankers
• Engine rooms and air-condition rooms
• Accommodation passages and cabin passages
• Galley and LPG storage areas
• Gas production, filling and storage facilities on shore

Five TOCA TS-303 combustible gas alarm units from different ship locations

Common Problems & Troubleshooting

• No power lamp: check supply voltage, fuse and cable connections.
• TROUBLE indication: check detector head cable for open / short circuit and the detector head itself.
• Meter not at zero in clean air: zero adjustment needed; old detector head may be drifting.
• Low response to test gas: span calibration needed or detector head sensitivity reduced (sensor poisoning by silicone, sulphur or lead compounds).
• False alarms: check alarm setpoint, humidity, and cable condition.
• Alarm cannot be reset: gas is still present or alarm relay / button fault.

Safety notes: isolate power before opening the unit. Do not work on gas detection equipment in a hazardous area without a permit. Always confirm the area is gas-free with a portable detector during repair.

Maintenance Tips

• Calibrate with certified test gas at the interval required by class / flag (typically yearly).
• Check zero in clean air regularly.
• Replace the detector head when sensitivity drops.
• Keep cable glands tight and the enclosure clean and dry.
• Test the alarm lamp and external alarm contact during routine checks.

Spare Parts & Replacement Availability

SM MARINE SERVICE™ supplies TOCA TS-303 combustible gas alarm units and related spares. Condition, calibration status and availability are subject to confirmation. For a quick quotation, please send:

• Photo of the front panel and nameplate (model, voltage, serial number)
• Detector head type and photo, if a head is needed
• Vessel name and IMO number
• Required quantity and delivery port

We ship worldwide by courier and air freight.

Why This Equipment Is Still Used

The TS-303 is simple, robust and easy to read, and many ships still use it as part of their fixed gas detection arrangement. Replacing a failed unit with the same model keeps wiring, mounting and crew training unchanged.

FAQ

1. What is the TOCA TS-303?
A single-point combustible gas alarm (fixed gas detector) made by Toka Seiki, Japan.

2. Which gases does it detect?
Combustible gases such as LPG, propane, butane and methane.

3. What does LEL=100 mean?
The meter reads 0–100% of the Lower Explosive Limit of the gas.

4. What power supply does it use?
AC100V as standard; DC12V and DC24V versions exist. Check the nameplate.

5. Which detector head is used?
Suppliers list diffusion type DZF(3) and suction type DZP (Not verified).

6. Do you supply PCBs for the TS-303?
Yes, on request. Send a photo of the board label; PCB numbers are not publicly listed.

7. What do the RESET and DIMM. buttons do?
RESET clears the alarm after gas is gone; DIMM. dims the lamps.

8. Are the units calibrated?
The units carry previous calibration labels (Cal 18 Sep 25, Due 18 Sep 26). Calibration status is confirmed with each quotation.

9. Can I buy several units?
Yes, single units or sets can be quoted.

10. Do you ship worldwide?
Yes, SM MARINE SERVICE™ ships to ports worldwide.

Short Product Description

The TOCA TS-303 is a combustible gas alarm made by Toka Seiki of Japan. It is a single-point fixed gas detector for continuous monitoring of LPG, propane, butane, methane and other flammable gases in the 0–100% LEL range, using the catalytic combustion principle. The front panel has an analog LEL meter, POWER, ALARM and TROUBLE indication, and RESET and DIMM. buttons, with a volt-free alarm contact for the ship's alarm system. It is used in pump rooms, engine rooms, air-condition rooms and accommodation passages. SM MARINE SERVICE™ supplies refurbished TOCA TS-303 units worldwide.

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SM MARINE SERVICE™ – Marine Automation & Navigation Equipment Supplier

Available Equipment Conditions: New • Used • Refurbished • Reconditioned (Specific product condition and availability are subject to confirmation.)

Stock Locations: Bangladesh • China

Services: Worldwide Shipping • Technical Support • Spare Parts Supply • Marine Equipment Sourcing

Samir Market, DT Road, Pahartali, beside CDA Market, Chattogram, Bangladesh

Mobile / WhatsApp / Viber: +88 01818 929292

Email: info@smmarineservice.com

Website: https://www.smmarineservice.com/

Contact SM MARINE SERVICE™ today for a quotation on the TOCA TS-303 combustible gas alarm and gas detector spare parts.

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