The 2026 (B.E. 2569) Flood at the Ban Plaeng Bridge, Pong Nam Ron, Chanthaburi

According to News1live, at about 18:00 on 24 September 2026 (B.E. 2569), the water level at the Ban Plaeng bridge in Pong Nam Ron, Chanthaburi rose so fast that it nearly reached the underside of the bridge. The Ban Plaeng route became impassable, the water kept rising, and people were warned to avoid the road.

Border areas like Pong Nam Ron are hilly, with fruit orchards and scattered communities. When water arrives fast it tends to bring mud, branches and debris. After it recedes, roads, homes, public buildings and farm sheds are coated with thick mud, conditions in which both people and equipment work much harder than usual.

Across the country, DDPM data as of 06:00 on 7 October 2026 (B.E. 2569) showed 27 provinces plus Bangkok affected, with 123 districts, 984 sub-districts, 1,154,875 households and more than 3.1 million people. Sprayers used during this period run hard for weeks on end, so correct care matters as much as choosing the right model.

Example Case: A Sprayer That Would Not Start on the Day It Was Needed Most

Note: this is a typical scenario built from situations we see often. It does not refer to any real organisation or person.

Ek leads the sanitation team of a local authority in an eastern border area. After the water receded, his team used a backpack mistblower to disinfect the village hall, the child development centre and the school for several days in a row. Every evening the team was exhausted, so the machine went into the back of the pickup with disinfectant still in the tank and mud caked on the body and the air intake screen.

On the fourth morning the engine was hard to start, the spray was uneven and less liquid came out than the setting called for. The team lost half the morning stripping and cleaning it while villagers waited for the childcare centre to be sprayed so it could reopen. Ek learned that no sprayer, however good, keeps performing if it is not cleaned and checked after every job, especially in the mud and humidity after a flood.

From then on his team followed a simple rule: "Spray, rinse right away, check before storing." That rule is the core of this article.

Why Post-Flood Spraying Is Especially Hard on a Sprayer

Disinfection after a flood differs from routine spraying in several ways that affect both people and machines.

• Mud dust and humidity. Dried mud turns into fine dust that can be drawn into the air intake and air filter, while high humidity puts metal parts at risk of rust.
• Days of continuous use. The machine runs all day, day after day, so parts wear faster if nobody checks them.
• Chemical left in the system. Disinfectant left overnight in the tank, lines and nozzle may form deposits or affect some components, depending on the product.
• Transport on damaged roads. The unit bounces around in a pickup on potholed roads, which can loosen screws and fittings.

The reason to disinfect after a flood is clear. Floodwater leaves many groups of microorganisms in homes and buildings: bacteria such as E. coli and Salmonella, plus the risk of Leptospira, the cause of leptospirosis; viruses such as norovirus and rotavirus, which cause diarrhoea; respiratory viruses such as influenza and RSV, which spread easily in shelters; and moulds on damp walls. A sprayer that is always ready is central to community recovery.

What Goes Wrong When a Sprayer Is Not Looked After

Not ready when needed. Floods often come in waves. If the unit fails after the first wave, the team works by hand in the next one.

Uneven spraying. A clogged nozzle or line reduces or destabilises the flow, so some surfaces receive too little disinfectant.

Repair costs and downtime. Major repairs caused by neglect cost budget and keep the machine out of service.

Risk to the operator. A leaking fitting can let chemical run down the operator's back, and a damaged harness can let the unit slip and cause injury.

Shorter working life. Equipment that should last for years may need replacing early.

Getting to Know the SOLO PORT 423 Before You Start

The SOLO PORT 423 is an engine-powered backpack mistblower made by SOLO Kleinmotoren GmbH in Germany. An engine drives a fan that creates a strong air stream, and liquid from the tank is fed into that stream, breaking into fine droplets that travel a long way. It is a mistblower, not a thermal fogger that uses heat.

Key specifications, according to manufacturer SOLO

• Single-cylinder 2-stroke engine, 72.3 cm³ displacement
• Power 3.0 kW (4.1 HP)
• Spray liquid tank 12 litres
• Maximum airflow 1,400 m³/h
• Horizontal reach about 12 metres
• Dry weight 11.0 kg
• Sound pressure at the operator 97 dB(A)

According to WHD's product information, the unit can deliver ULV-type output with droplets below 30 microns, saving chemical, although real droplet size depends on the nozzle and settings. WHD lists the parts operators should know: a Nikasil-coated cylinder, a BING float carburettor, electronic ignition, a rotatable spray tube, a long nozzle and wide-angle diffuser, a UV-resistant translucent tank with a wide filler opening, a one-hand control lever for throttle, dosing and stop, a padded harness and four-point anti-vibration mounts.

One important rule: for any figure not given in this article, such as the fuel mix ratio, follow only the manufacturer's manual supplied with the machine, and ask the dealer if you are unsure.

How to Use the SOLO PORT 423 for Disinfection in Flooded Areas

1. Check the machine before every use

Check the harness, buckles and back pad for tears. Check the tank and lid for cracks, and the lines and fittings for leaks. Make sure the air filter is not clogged with mud dust, that all fixing screws are tight, and that the control lever moves freely and really stops the engine.

2. Wash mud out of the area before spraying

The sprayer only delivers the liquid. How well it disinfects depends on the chemical, and the chemical works best on clean surfaces, so always remove rubbish and wash out mud first.

3. Mix the disinfectant by the label

Use a registered disinfectant such as Chemgene HLD4H at the dilution the label specifies. Mix in a separate container and strain it before pouring it into the 12-litre tank. Never combine different chemicals yourself, and use clean water, never floodwater or cloudy water, because sediment will block the nozzle.

4. Refuel safely

Refuel with the engine off and cool, outdoors and away from flames. Use fuel mixed to the ratio in the manufacturer's manual, wipe up spills before starting, and start the engine a sensible distance from where you refuelled.

5. Wear full protective equipment

Ear muffs or plugs, chemical-resistant gloves, goggles or a face shield, a respirator suited to the chemical, long sleeves or coveralls and boots, following the label and safety data sheet (SDS).

6. Start the engine and lift the unit correctly

Set the unit on level ground and start it following the manual. Let it idle briefly, then lift it onto your back with bent knees and a straight back, or ask a teammate to help. Tighten the harness, because a full tank brings the weight to about 23 kg or more.

7. Spray with a steady rhythm

Open the throttle to the airflow you need, then open the liquid flow. Walk at a constant pace and sweep the tube slowly across walls, floors and corners. Start at the far end and back out. Outdoors, spray with the wind, never into it, and never toward people, pets, drinking water or food containers.

8. Shut off the liquid before lowering the throttle

At the end of each pass, close the liquid flow first, then reduce the throttle, so chemical does not dribble out without air behind it. Stop the engine with the control lever and set the unit down on level ground.

9. Cordon off and wait

Close off the sprayed area, leave the disinfectant on surfaces for the contact time on the label, ventilate, and let people back in only after the stated re-entry time.

How to Clean and Care for the SOLO PORT 423 After Every Job

1. Deal with leftover mix

Try to mix only what the job needs. Dispose of any leftover as the label directs, never into streams, canals or public drains.

2. Flush the tank and liquid system with clean water

Pour a little clean water into the tank, swirl it, then run the engine and spray the clean water through the system in a safe spot to push out chemical left in the lines and nozzle. Repeat until the water runs clear, then empty the tank.

3. Remove and wash the strainer and nozzle

Take out the filler strainer and any nozzle parts the manual says are removable. Wash them in clean water with a soft brush. Never poke the nozzle holes with wire or anything hard, as it deforms the opening and spoils the spray.

4. Clean the body and air intake

Wipe mud and chemical residue off the body, fuel tank and harness with a damp cloth. Clear mud and leaves from the fan's intake screen. Never aim a pressure washer directly at the engine.

5. Check the air filter

In muddy post-flood work the air filter clogs faster than usual. Remove it, inspect it and clean it as the manual describes, and replace it if damaged. A dirty filter makes starting hard and reduces power.

6. Check the spark plug and ignition on schedule

Inspect the spark plug at the intervals the manual recommends. Hard starting or rough running can be a sign to check the plug or air filter. If in doubt, have the dealer inspect it.

7. Check the harness and anti-vibration mounts

Make sure the harness, back pad and all four anti-vibration mounts are intact and secure, since they reduce the vibration reaching the operator.

8. Clean your PPE and yourself

Rinse gloves, goggles and boots before taking them off, store the respirator as its maker recommends, shower and change, and wash work clothes separately from family laundry.

9. Keep a usage log

Record running hours, areas sprayed, chemicals used and anything unusual about the machine. The log helps plan maintenance and documents the organisation's work.

Storage Between Flood Seasons

• Store the unit somewhere dry, shaded and ventilated, above any previous flood level and away from heat and flames.
• Clean and dry the tank before storage. Never store the machine with chemical in the tank.
• For storage of several weeks or more, handle the fuel in the tank and carburettor as the manufacturer's manual describes.
• Keep disinfectant separate from fuel, in its original labelled container, out of children's reach.
• Before the next rainy season, start the engine and spray clean water to confirm it is ready for real work.
• Check consumables such as the air filter and spark plug, and order spares in advance through the dealer.

10 Reasons the SOLO PORT 423 Pays Off When Cared For Properly

1. Covers large areas. Maximum airflow of 1,400 m³/h, according to SOLO.
2. About 12 metres of horizontal reach. The operator does not need to approach every surface, which lowers chemical exposure.
3. A translucent 12-litre tank. You can see the level, and the wide filler makes rinsing easy, according to WHD.
4. No mains power needed. It works in border areas or communities where power has not returned.
5. A durable engine. WHD lists a Nikasil cylinder and MAHLE and BING components.
6. One-hand control. Shut off the liquid and stop the engine instantly from the lever.
7. Less vibration. A padded harness and four-point anti-vibration mounts, according to WHD.
8. Saves chemical. According to WHD's product information, it can deliver ULV-type droplets below 30 microns.
9. Simple routine care. Rinse, check, store, by the manual. Your team can do it after every shift.
10. Years of service. Equipment that serves both post-flood recovery and year-round hygiene work. Ask for a quote on the SOLO PORT 423 product page.

Before and After a Good Care Routine

Safety When Using and Servicing the SOLO PORT 423

• Hearing protection. Sound pressure at the operator is 97 dB(A), according to SOLO. Wear ear muffs or plugs every time, including test runs after maintenance.
• Vibration and working time. Limit spraying time per session, rotate operators and take regular breaks.
• Chemical PPE. Follow the label and SDS, including while rinsing a machine that still holds chemical.
• Refuelling. Engine off and cool, away from flames.
• Weight. 11.0 kg dry and about 23 kg or more when full. Take care lifting on slippery mud.
• Keep people and pets out of the spray zone, and follow the re-entry time on the label.
• Service only with the engine stopped. Never remove parts or put hands near the fan while it is running.
• Training. Every operator should be trained in use and care from the manual and by the dealer.

Anyone who waded through floodwater and develops a fever, calf pain, diarrhoea or an infected wound should see a doctor and mention the flood exposure.

A Simple Daily Routine for Team Leaders

During a flood response, routines break down because everyone is tired. A short routine that the team leader checks every day keeps the SOLO PORT 423 working through weeks of recovery.

• Morning: walk-around check of the harness, tank, lines and air filter, then a short test run with clean water before loading the truck.
• Before each site: confirm the chemical, dilution and contact time from the label, and confirm that people and pets are out of the zone.
• During the day: rotate operators, enforce hearing protection and water breaks, and never refuel a hot engine.
• Evening: flush the system, wash the strainer and nozzle, wipe off mud, clean the intake screen and note any problem in the log.
• Weekly: a closer look at the air filter, spark plug, screws and anti-vibration mounts, with parts ordered through the dealer before they run out.

Assign one person to sign off on each step. Shared responsibility often means nobody does it.

No Machine Yet, or Need Urgent Help?

If your organisation does not yet have a unit, or needs a one-off urgent job, the WHD disinfection spraying service is a separate option. For other angles on this machine, read the Thai articles on fighting dengue for municipalities and SAOs and spraying against emerging disease for provincial public health offices.

Frequently Asked Questions (FAQ)

How do I use a SOLO PORT 423 for the first time?

Read the whole manufacturer's manual, get training from the dealer, check the unit, refuel as the manual says, mix chemical by the label, put on PPE, and test-spray clean water before real work.

What fuel mix ratio does the SOLO PORT 423 use?

Use only the ratio in the manufacturer's manual supplied with the unit. If unsure, ask WHD on 065-556-6294 or LINE @whd268.

How do I clean a backpack sprayer after use?

Dispose of leftover mix by the label, rinse the tank, spray clean water through the system, wash the strainer and nozzle, wipe the body and check the air filter.

Can I leave disinfectant in the tank overnight?

It is not recommended. Mix only what you need and rinse the tank after every shift to prevent deposits and wear on parts.

Why is my mistblower hard to start?

Common causes are a dirty air filter, a worn spark plug or old fuel left too long. Check them as the manual describes, and if the problem remains, have the dealer inspect the unit.

What should I do if the nozzle is blocked?

Stop the engine, remove the nozzle as the manual describes, wash it in clean water with a soft brush, never poke it with wire, and always mix chemical with clean water.

Is the SOLO PORT 423 a thermal fogger?

No. It is a mistblower that uses air, not heat.

What is the SOLO PORT 423 price, and where can I ask about spare parts?

Ask about price and parts on the product page, call 065-556-6294 or add LINE @whd268.

Want a SOLO PORT 423 for your organisation? Ask for a quote today

View SOLO PORT 423 and Request a Quote

For specifications, a demonstration or a quotation, call 065-556-6294 or add LINE @whd268. The World Health Disinfection team can also advise on choosing a registered disinfectant and on safe operation.

Related Reading and Sources

• SOLO Port 423 against dengue, for municipalities and SAOs (Thai)
• SOLO Port 423 for provincial public health and emerging disease (Thai)
• Chemgene HLD4H disinfectant
• WHD disinfection spraying service (an option if you prefer not to buy)
• News1live, 24 Sep 2026 (B.E. 2569): water nearly reaches the Ban Plaeng bridge, Pong Nam Ron, Chanthaburi (Thai)
• Government PR Department: flood summary, DDPM data as of 7 Oct 2026 (B.E. 2569)
• CDC: Floods and cleanup guidance
• Department of Disease Control, Thailand