Wöhler measuring instruments for heating, ventilation, gas and refrigeration
Wöhler measuring instruments are German-made handheld analysers, testers and meters used by heating, gas, ventilation and refrigeration technicians to check that appliances burn cleanly, pipework and flues are tight, buildings are properly ventilated and refrigeration circuits are correctly charged.
This page covers 40 instruments across seven application areas, from the A 550 flue gas analyser to the RL 300 refrigerant leak detector. Each description explains what the instrument measures, where it is used and how to choose between similar models. All are supplied across South Africa and to neighbouring countries from our Cape Town base.
Manufacturer: Wöhler Technik GmbH, a family-owned company founded in 1932 in Bad Wünnenberg, Germany, that develops and produces measuring, inspection and cleaning equipment for building services.
Also written as: Woehler and Wohler. The model names are identical under every spelling.
Standards referenced in this range: EN 50379 (flue gas analysers), EN 12599 (ventilation handover), DIN EN 14624:2020 (refrigerant leak detectors), EN 806 and EN 1610 (water and waste water pipes), VDI 4206 (solid fuel moisture).
Questions? Call +27 21 911 5835 or email sales@ecotao.co.za
How to choose the right Wöhler instrument
Start from the job you need to do. The table matches common heating, gas, ventilation and refrigeration tasks to the Wöhler instrument designed for it.
← Scroll to see full table →
| Task | Recommended instrument | Why |
|---|---|---|
| Tune a gas, oil or wood-fired boiler or heater | A 450 or A 550 | A 550 adds the 4 Pa test and wood moisture |
| Measure emissions on an industrial boiler or CHP engine | A 550 Industrial | SO₂, NOx and NDIR CO₂ sensors; flow measurement |
| Check an open-flued appliance for flue gas spillage | TI 410 | Three independent spillage indicators |
| Find a gas leak on LPG or natural gas pipework | GS 220, then GS 300 | Detect first, then pinpoint |
| Pressure-test gas, drinking water or sewer pipes | M 603 (with SC 660 for high pressure) | Automatic test sequences |
| Prove a chimney or flue system is tight | DP 600 | Leakage rates up to 200 m³/h |
| Measure ductwork leakage | DP 700 | Ventilation systems and components |
| Test building airtightness | BC 600 | Automatic blower door measurement |
| Balance a ventilation system or check vent airflow | DC 410 FLOW, FA 410 or FA 430 | DC 410 FLOW for ducts; FA 410/FA 430 at the grille |
| Monitor CO₂ in a classroom or office | CDL 210 or IQ 300 | CDL 210 logs data over time |
| Report on full indoor air quality, including CO | KM 410 | Six IAQ values, logging and printed reports |
| Investigate damp and mould risk | IR Hygrotemp 24 and HBF 420 | Dew point plus material moisture |
| Measure gas or burner pressure | DM 602 | Dedicated manometer, mbar or Pa version |
| Measure low air velocity in a duct | TA 200 | Hot wire sensor reads slow-moving air |
| Decide whether ductwork needs cleaning | DTEST | Measured dust surface density |
| Check heat pump or fan noise | SP 22 | Sound pressure level on site |
| Check heating system water quality | WA 335 | Prevents scale and corrosion damage |
| Check firewood or wood chips before burning | HF 300 or HF 550 | HF 550 covers bulk fuels to VDI 4206 |
| Find a refrigerant leak | RL 300 or RL 200 | RL 300 meets DIN EN 14624:2020 |
| Service or commission a heat pump or AC unit | SC 660 with MR 660, VP 400 and RS 400 | Modular Smart Connect system |
4 instruments
Wöhler flue gas analysers
A flue gas analyser draws a sample from the flue of a boiler, burner or stove and measures oxygen (O₂) and carbon monoxide (CO) with electrochemical sensors, then calculates CO₂, excess air and combustion efficiency. Technicians use the readings to tune the air-fuel ratio: too little air produces CO and soot, too much air sends heat up the chimney. Wöhler analysers also carry out draught, differential pressure and ambient CO checks from the same handset.
Flue gas analyser
Wöhler A 550 Flue Gas Analyser
The A 550 is Wöhler's service analyser for residential and commercial boilers, gas heaters and solid-fuel appliances. Analyses, inspections and burner settings are driven from a smartphone-style touchscreen, so a full combustion test, draught reading and report can be completed without paging through menus. Coded connections for the 4 Pa test let one instrument confirm that a room-air-dependent appliance is getting enough combustion air, and a wood moisture function to VDI Guideline 4206 checks firewood before a stove emission test.
- Large 7-inch touchscreen display
- 4,000 ppm CO sensor as standard
- Coded connections for the 4 Pa combustion air test
- Wood moisture measurement to VDI 4206
- Field-replaceable sensors, including optional NO and NO₂
Best for: Heating contractors servicing gas, oil and wood-fired appliances
Emission analyser
Wöhler A 550 Industrial Flue Gas Analyser
The A 550 Industrial extends the A 550 platform for emission measurement on larger plant. It measures to EN 50379 and adds sensor options for SO₂, NO, NO₂ and high-range CO, with an NDIR sensor for CO₂ from 0 to 40 vol%. A dual-port digital pressure sensor works with S-tubes and Prandtl probes to measure flue gas velocity and volume flow, and a CHP filter allows CO measurement on combustion engines. Sample probes are available in several lengths for hard-to-reach stacks.
- Optional sensors: SO₂ 5,000 ppm, NO 3,000 ppm, NO₂ 1,000 ppm, CO 100,000 ppm
- NDIR CO₂ sensor, 0–40 vol%
- Flue gas velocity and flow via dual-port pressure sensor
- PC software with export to Excel, plus mobile app
Best for: Industrial boilers, process burners, CHP engines and emission audits
Compact flue gas analyser
Wöhler A 450 Flue Gas Analyser
The A 450 is Wöhler's compact analyser: small, light and housed in a robust casing, yet it offers the full set of combustion measurement and tuning functions. All measured and calculated values are shown together on a 5-inch colour touchscreen, and the flue gas analysis app mirrors the readings to a phone or tablet, which is useful when adjusting a large burner away from the handset. The sensors sit behind multiple filters, and the condensate trap pulls out for a quick filter change on site.
- 5-inch colour touchscreen
- CO sensor options: 5,000, 10,000 or 100,000 ppm
- Optional 3,000 ppm NO sensor (A 450 NO versions)
- Wi-Fi, USB and IR interfaces (A 450 L)
Best for: Service technicians who want a full-function analyser at a lower cost
Flue gas spillage indicator
Wöhler TI 410 Dew Point Indication
The TI 410 checks for flue gas spillage during flue path inspections. Water vapour escaping from a flue condenses on the cool sensor, and the instrument flags this three ways: a visual signal, an audible signal and the temperature rise at the sensor. Using three independent indicators gives a reliable result even in noisy or poorly lit plant rooms. A small sensor plate reaches draught diverters and other tight locations.
- Visual, audible and temperature-rise indication
- Small sensor plate for inaccessible spots
- Dedicated to flue gas spillage checks
Best for: Flue path inspections on open-flued gas appliances
Wöhler flue gas analysers compared
← Scroll to see full table →
| A 450 | A 550 | A 550 Industrial | |
|---|---|---|---|
| Intended use | Residential and commercial servicing | Residential and commercial servicing and inspections | Emission measurement on larger plant and engines |
| Display | 5-inch colour touchscreen | 7-inch touchscreen | Touchscreen, A 550 platform |
| 4 Pa combustion air test | Not a listed feature | Yes, coded connections | Dual-port pressure sensor for flue gas velocity and flow |
| Wood moisture (VDI 4206) | Not a listed feature | Yes | Yes |
| CO sensor | 5,000, 10,000 or 100,000 ppm | 4,000 ppm | 100,000 ppm (COHigh) |
| Other gas sensors | Optional 3,000 ppm NO | NO, NO₂ | SO₂, NO, NO₂, NDIR CO₂ |
| Measurement standard | See data sheet | EN 50379 | EN 50379 |
1 instrument
Wöhler soot and particulates
Soot testing shows how completely an oil burner or solid-fuel appliance is burning. A manual pump draws a fixed volume of flue gas through filter paper, and the darkness of the spot is compared against a reference scale. A high soot number indicates poor atomisation, low combustion air or a fouled heat exchanger.
Manual soot pump
Wöhler RP 72 Soot Test Pump
The RP 72 is a rugged manual soot tester for oil burners and solid-fuel appliances. Ten pump strokes pull a set sample volume through the filter paper, so results are comparable from one test to the next. The long hose reaches awkward measurement openings. The soot spot is placed off-centre on the filter, which leaves room for several tests on one paper and makes side-by-side comparison easy.
- 10-stroke sampling
- Long hose for hard-to-reach test points
- Off-centre spot allows several tests per filter
Best for: Oil burner servicing and combustion checks on solid-fuel appliances
8 instruments
Wöhler pressure and leakage testers
Pressure and leakage testers prove that a system holds gas, water or air. Gas pipework is pressurised and monitored for pressure drop. Flue systems and ductwork are tested by measuring the airflow needed to hold a set test pressure, which gives the leakage rate. Gas sniffers then pinpoint where a leak is.
Flue and chimney tightness tester
Wöhler DP 600 Leakage Tester
The DP 600 tests the tightness of chimneys and flue gas systems. Select the installation type in the menu and the instrument automatically sets the required test pressure for P1, H1, N1 and N2 flue classes, then calculates the leakage rate. A variable mode lets you set your own test pressure and limit, covering P2 and H2 systems and ventilation ductwork. It also performs the 4 Pa test to confirm combustion air supply and checks the tightness of room-sealed stoves.
- Leakage rates up to 200 m³/h
- Automatic test pressure for flue classes P1, H1, N1, N2
- Positive and negative pressure testing
- 4 Pa combustion air test; results printed on a thermal printer
Best for: Chimney sweeps, flue installers and CHP exhaust systems
Ductwork leakage tester
Wöhler DP 700 Leakage Tester
The DP 700 measures air leakage in ventilation and air-conditioning ductwork and components. Leaky ductwork forces fans to move more air than the building needs, which wastes energy and unbalances airflow to rooms. Quantifying the leakage rate lets contractors verify new installations at handover and find where existing systems are losing air.
- Leakage testing of ventilation systems and components
- Supports duct airtightness verification at handover
- Identifies energy losses in HVAC distribution
Best for: HVAC contractors commissioning or auditing duct systems
Blower door system
Wöhler BC 600 Blower Check
The BC 600 measures the airtightness of a building envelope or a single room. A fan mounted in a door or window pressurises and depressurises the space while the instrument logs the airflow needed to hold each pressure step. Measurement is fully automatic, and the device does not need to be turned around to switch between positive and negative pressure. Its wide airflow range covers small apartments through to larger rooms, with evaluation and documentation completed on site.
- Fully automatic blower door measurement
- Positive and negative pressure without turning the fan
- Single-mode and multi-mode versions available
- On-site evaluation and documentation
Best for: Energy auditors, green building assessments and leak tracing
Pipework pressure tester
Wöhler M 603 Leakage Tester
The M 603 pressure-tests gas lines, drinking water pipes and waste water pipes from one instrument. It is DVGW-certified and TÜV-tested, and runs automatic test sequences to the German gas guideline TRGI 2018, EN 806 for drinking water and EN 1610 for sewers. The automatic sequence steps the user through each test and records the result, which reduces operator error. With an additional locator, the M 603 also traces metallic pipes.
- Tests gas, drinking water and waste water pipework
- Automatic test sequences to TRGI 2018, EN 806 and EN 1610
- DVGW-certified and TÜV-tested
- Pairs with the SC 660 via Bluetooth for high-pressure water tests
Best for: Plumbers and gas installers who need one tester for every pipe type
Pressure and temperature module
Wöhler SC 660 Smart Connect
The SC 660 is a compact pressure and temperature sensor rated to 60 bar, which makes water pressure tests with water straightforward. It has its own display for stand-alone use and can connect to the M 603 via Bluetooth. On refrigeration systems and heat pumps it attaches directly to the service port, so operating pressure, superheat and subcooling can be checked without hoses and without losing refrigerant. The free Smart Connect app controls measurements and saves the results as a PDF report.
- Pressure measurement up to 60 bar
- Own display, or Bluetooth link to M 603 and app
- Hose-free refrigerant pressure checks at the service port
- PDF reports from the Smart Connect app
Best for: Water pipe pressure tests and quick refrigeration system checks
Digital manometerNew model
Wöhler DM 602 Digital Manometer
The DM 602 is a digital manometer for differential pressure work: gas supply pressure, burner nozzle pressure, draught and duct pressure. It shows pressure and temperature together, and Wöhler sells it in two display versions, one reading in millibar and one in pascal, so you can match it to the units your trade works in.
- Differential pressure with temperature display
- mbar version and Pa version available
- For gas pressure, burner settings and draught checks
Best for: Gas installers and heating technicians needing a dedicated manometer
Combustible gas detector
Wöhler GS 220 Gas Sniffer
The GS 220 finds leaks on pipework carrying combustible gas. It is calibrated for methane (natural gas) and LPG, responds quickly and is highly sensitive. A staged LED bar and an audible signal rise as gas concentration increases, guiding you towards the leak. The 440 mm gooseneck bends into meter boxes, behind appliances and along ceiling runs.
- Calibrated for methane (CH₄) and LPG
- Staged LED and acoustic signal
- 440 mm flexible gooseneck
- Fast response time
Best for: LPG and natural gas installations, including SA LPG conversions
Gas leak locator
Wöhler GS 300 Gas Leak Detector
Wöhler lists this model as both the GS 300 Gas Leak Detector and the GS 300 Gas Sniffer; they are the same instrument. Small leaks on natural gas lines, such as hairline pipe cracks or aged seals, often occur at joints and appliance connections. Once a pressure test or detector has shown that a leak exists, the GS 300 locates it precisely. It also supports serviceability tests on gas lines and a quick, reliable inspection of the visible parts of a gas installation.
- Pinpoints leak position at joints and connections
- Supports serviceability testing of gas lines
- Quick visual installation inspections
Best for: Locating leaks after a failed tightness test
Wöhler leak and tightness testers compared
← Scroll to see full table →
| What it tests | How it tests | Typical user | |
|---|---|---|---|
| GS 220 | Combustible gas leaks (CH₄, LPG) | Gas sensor on 440 mm gooseneck | Gas installers |
| GS 300 | Exact leak position on gas lines | Locates a known leak | Gas installers |
| M 603 | Gas, drinking water and sewer pipework | Pressure drop, automatic sequences | Plumbers and gas fitters |
| DP 600 | Chimneys and flue gas systems | Airflow at set test pressure | Flue installers, sweeps |
| DP 700 | Ventilation ductwork | Air leakage rate | HVAC contractors |
| BC 600 | Building or room envelope | Blower door pressurisation | Energy auditors |
8 instruments
Wöhler ventilation and indoor air quality
Ventilation instruments confirm that a building moves the right amount of fresh air and that the air people breathe is safe. They measure differential pressure, airflow at grilles and ducts, temperature and humidity, and gases such as CO₂ and CO. CO₂ is the standard proxy for ventilation adequacy because people exhale it: a rising CO₂ reading means stale air is building up.
Pressure and flow meter
Wöhler DC 410 FLOW Differential Pressure and Flow Meter
The DC 410 FLOW combines differential pressure, air velocity and volume flow, temperature and relative humidity in one handheld instrument. It is designed for testing to EN 12599, the European standard for test procedures when handing over installed ventilation and air-conditioning systems. Its no-drift sensor technology holds accuracy during long balancing sessions, and a four-button keypad allows one-handed use on a ladder.
- Pressure, airflow, temperature and humidity in one unit
- Testing to EN 12599 for system handover
- No-drift pressure sensor technology
- One-handed operation with 4-button keypad
Best for: Commissioning and balancing ventilation and AC systems
Vane anemometers
Wöhler FA 410 and FA 430 Fan Anemometers
The FA 410 measures air speed, temperature and humidity at supply and extract vents. The FA 430 adds CO₂ measurement, so ventilation performance and air quality are read from one instrument. Both are sold on their own or as a set with a funnel, and with the measuring cone or funnel they give volume flow directly at air terminals, so room-by-room airflow can be checked against design values. They also help trace draughts and air leaks.
- FA 410: air speed, temperature and humidity
- FA 430: adds CO₂ measurement
- Available on their own or as a set with funnel
- Direct volume flow with cone or funnel
Best for: Checking residential and commercial vent airflow
Ambient CO meter
Wöhler CM 220 CO-Meter
The CM 220 measures carbon monoxide in ambient air and helps trace CO escaping from furnaces, water heaters and stoves. It compares readings against the maximum workplace concentration (MWC), so a technician immediately knows whether a space is safe to work in. A precise electrochemical sensor, visual and audible alarms, and single-button operation make it suitable as a personal safety check on every call-out.
- Electrochemical CO sensor
- Maximum workplace concentration (MWC) evaluation
- Visual and acoustic alarms
- One-button operation
Best for: CO safety checks around fuel-burning appliances
CO₂ monitor and logger
Wöhler CDL 210 CO₂ Data Logger
The CDL 210 is a CO₂ monitor, often called a CO₂ traffic light, for continuous indoor air quality monitoring. A true infrared (NDIR) sensor measures CO₂ up to 9,999 ppm, and the large display shows CO₂, temperature and humidity together. Visual and acoustic alerts trigger when a preset CO₂ limit is exceeded, prompting occupants to ventilate. Readings are logged at adjustable intervals and evaluated with Wöhler indoor climate software.
- NDIR CO₂ measurement to 9,999 ppm
- CO₂, temperature and humidity on one display
- Adjustable alarm threshold
- Data logging with indoor climate software
Best for: Offices, classrooms, clinics and meeting rooms
Hot wire anemometerNew model
Wöhler TA 200 Hot Wire Anemometer
A hot wire anemometer measures air velocity from the cooling effect of moving air on a heated sensor, which makes it far more sensitive at low speeds than a vane. The TA 200 therefore suits slow-moving air in large ducts, extract grilles and displacement ventilation, where a vane anemometer barely turns. Its slim probe fits through small test openings in ductwork.
- Accurate at low air velocities
- Slim probe for small duct test holes
- Complements vane anemometers for grille measurement
Best for: Duct traverses and low-velocity airflow checks
CO measuring deviceNew model
Wöhler KM 405 CO Measuring Device
The KM 405 measures carbon monoxide in the air around fuel-burning appliances, so technicians can check that CO is not escaping into the room during servicing or after a complaint. It sits alongside the CM 220 in the Wöhler range as a dedicated CO instrument.
- Ambient carbon monoxide measurement
- For appliance servicing and CO complaints
- Portable handheld instrument
Best for: CO safety checks in plant rooms and dwellings
Indoor air quality meterNew model
Wöhler KM 410 Indoor Air Quality Meter
The KM 410 gives the full indoor climate picture from one handheld instrument: CO₂, air temperature, humidity, CO, dew point and wet bulb temperature. CO₂ is measured by NDIR, the infrared method that holds its accuracy far better over time than cheaper sensors, and the added CO sensor matters where fuel-burning appliances share the space, since exhaust gas backflow can push CO into a room. A data logger records readings over time, and min/max, hold, alarms and a blue backlit display make it workable in plant rooms and dark corners. Results go to a PC over mini USB for analysis, or print on site through the Wöhler TD 100 thermal printer. Wöhler also sells it as the KM 410 IAQ Instrument with a calibration kit.
- CO₂, temperature, humidity, CO, dew point and wet bulb in one meter
- NDIR carbon dioxide measurement
- Data logger with min/max, hold and audible and visual alarms
- USB to PC software, or printed reports via the TD 100 printer
Best for: Consultants and facilities teams verifying HVAC performance and reporting on indoor air quality
CO₂ meter
Wöhler IQ 300 CO₂ Meter
The IQ 300 evaluates indoor air quality from measured CO₂. People exhale moisture, CO₂ and, when ill, viruses, so a high CO₂ level signals that a room urgently needs fresh air and that other pollutants are likely accumulating too. The IQ 300 suits classrooms, waiting rooms and seminar rooms where occupancy changes through the day.
- CO₂-based air quality evaluation
- Designed for shared rooms
- Clear ventilation prompts
Best for: Schools, waiting areas and training venues
9 instruments
Wöhler temperature and humidity
Temperature and moisture instruments diagnose heating performance, building damp and fuel quality. Differential thermometers check flow and return temperatures on heating circuits, hygrometers calculate dew point to assess mould risk, and moisture meters measure water content in timber, building materials and firewood.
Differential thermometer
Wöhler DT 310 Differential Temperature Meter
The DT 310 measures two temperatures at once and shows the difference between them, which is the quickest way to judge heat transfer across a boiler, radiator or heat exchanger. Clamp or surface probes on flow and return pipes give an immediate delta-T reading. It also measures surface temperatures on flue lines. MIN and MAX values are stored with date and time stamps.
- Simultaneous display of both readings and the difference
- Accepts type K, J and T thermocouple probes
- MIN/MAX memory with date and time stamp
- Two probes required for differential readings
Best for: Hydronic heating balancing and heat pump performance checks
Hygrometer with IR sensor
Wöhler IR Hygrotemp 24
The IR Hygrotemp 24 measures air temperature and relative humidity and calculates the dew point. An additional infrared sensor reads wall and window surface temperatures without contact. If a surface is at or near the dew point, condensation and mould are likely, so this one instrument can flag mould-risk areas during a home inspection.
- Air temperature, relative humidity and dew point
- Infrared surface temperature sensor
- Mould-risk assessment on surfaces
- Indoor comfort analysis
Best for: Damp and mould investigations and home inspections
Thermo-hygrometer
Wöhler RF 220 Hygrotemp
The RF 220 measures relative humidity and air temperature and calculates both dew point and wet-bulb temperature. It gives a quick humidity check in offices and buildings, verifies air-conditioning output, and supports building inspections for mould and other humidity-related problems.
- Relative humidity and air temperature
- Calculated dew point and wet-bulb temperature
- Quick spot checks in buildings
Best for: AC performance checks and humidity surveys
Wood and building materials moisture meter
Wöhler HBF 420 Moisture Meter
The HBF 420 combines two measuring methods in one instrument. Electrical resistance measurement with pins gives an accurate reading in timber, while dielectric (capacitive) measurement scans walls and screeds without damaging the surface. It is used for building diagnostics such as damage analysis and leak detection, for checking substrates before painting or laying floor coverings, and for assessing wood fuel.
- Resistance and dielectric measurement in one unit
- Wood and building material settings
- Non-destructive scanning of walls and floors
Best for: Leak detection, flooring preparation and damp surveys
Wood moisture meter
Wöhler HF 300 Wood Moisture Meter
The HF 300 is a small, straightforward wood moisture meter. Its needles push up to 5 mm into a log, and the large display shows the reading immediately with no setup. It is ideal for checking that firewood is dry enough to burn cleanly.
- Needle electrodes penetrate up to 5 mm
- Large, easy-to-read display
- Compact and ready to use immediately
Best for: Quick firewood checks by sweeps, stove installers and suppliers
Solid fuel moisture meter
Wöhler HF 550 Wood Moisture Meter
Wet fuel is a common cause of high emissions from fireplaces and stoves. The HF 550 measures the moisture of firewood logs and of bulk materials such as wood chips. It automatically recognises which probe is connected, switches to the matching menu and guides the user through the procedure, so measurements conform to VDI 4206 Part 4 with little effort.
- Measures logs and bulk materials such as wood chips
- Automatic probe recognition
- Guided measurement to VDI 4206 Part 4
- Professional Set and matching FW 550 wood moisture scale available
Best for: Biomass fuel quality control and stove emission testing
Infrared thermometer
Wöhler IR Temp 310 Infrared Thermometer
The IR Temp 310 measures surface temperature without contact, including in places you cannot reach. It detects thermal bridges and other temperature differences in real time at both short and long distances. Set the emissivity for the surface, aim with the laser spot, and read and store the temperature on the colour display.
- Non-contact surface temperature
- Adjustable emissivity
- Laser spot targeting
- Colour display with value storage
Best for: Thermal bridge detection and heating system diagnostics
Infrared thermometerNew model
Wöhler IR Temp 210 Infrared Thermometer
The IR Temp 210 is the simpler of Wöhler's two infrared thermometers. It reads surface temperature without contact for everyday checks such as flow and return pipes, radiators, flue surfaces and cold spots on walls. Choose it when you want a quick non-contact reading and do not need the adjustable emissivity and storage of the IR Temp 310.
- Non-contact surface temperature
- Simpler alternative to the IR Temp 310
- Pocket-sized for everyday service work
Best for: Quick temperature spot checks on site
Globe thermometerNew model
Wöhler GT 300 Globe Thermometer
A globe thermometer measures radiant heat. A temperature sensor sits inside a matt black globe that absorbs heat radiated from surrounding surfaces, sun-heated roofs and hot equipment, so the reading reflects what a person actually feels rather than air temperature alone. The GT 300 extends the Wöhler temperature range to thermal comfort and heat-stress assessment in workplaces and buildings.
- Measures radiant temperature via a black globe
- Assesses thermal comfort beyond air temperature
- Relevant to workplace heat-stress checks
Best for: Thermal comfort surveys in factories, warehouses and offices
7 instruments
Wöhler refrigeration and heat pump tools
Refrigeration tools cover the whole service cycle on air-conditioning units, cold rooms and heat pumps: finding refrigerant leaks, reading system pressures and temperatures, evacuating the circuit, recovering refrigerant and weighing the charge back in. Wöhler builds these as a modular system around the SC 660 Smart Connect and the free Smart Connect app.
Refrigerant leak detector
Wöhler RL 300 Refrigerant Leak Detector
The RL 300 meets DIN EN 14624:2020, a demanding test standard for refrigerant leak detectors that relatively few devices achieve. Its high sensitivity reliably finds the smallest leaks, and refrigerant concentration is shown on an 11-level digital bar graph. Visual, acoustic and vibration alarms can each be switched off, so the detector can be used silently or felt in a noisy plant room. Automatic zeroing removes background readings.
- Fulfils DIN EN 14624:2020 and the F-Gas Regulation
- 11-level digital bar graph
- Visual, acoustic and vibration alarms
- Automatic zero setting
Best for: Contractors who need standard-compliant leak checks
Refrigerant leak detector
Wöhler RL 200 Refrigerant Leak Detector
The RL 200 detects refrigerant leaks down to a sensitivity of 3 g/a. It was developed to the requirements of the F-Gas Regulation, and its digital display keeps measured values clear while you work around joints and valves. Automatic zero setting simplifies handling so the focus stays on finding the leak.
- Sensitivity 3 g/a
- Developed to F-Gas Regulation requirements
- Digital display
- Automatic zero setting
Best for: Routine leak checks during maintenance visits
Digital manifold
Wöhler MR 400 Refrigerant Manifold
The MR 400 is a digital manifold for all common refrigerants. It shows high and low pressure, calculates superheat and subcooling, determines refrigerant operating states and measures vacuum, all on one digital display. Lockable connection hoses with ball valves keep refrigerant loss to a minimum when connecting and disconnecting.
- High and low side pressure display
- Superheat and subcooling calculation
- Vacuum measurement
- Lockable hoses with ball valves
Best for: Refrigeration and heat pump maintenance
Refrigerant scale
Wöhler RS 400 Refrigerant Scale
The RS 400 weighs refrigerant pressure cylinders so you know exactly how much refrigerant goes into or comes out of a system. Accurate weighing is essential for charging a circuit to the manufacturer's specification. It works with all common refrigerants, has a digital display and packs into a carrying bag.
- Precise weighing of refrigerant cylinders
- Suitable for all common refrigerants
- Digital display
- Supplied with carrying bag
Best for: Charging and recovering refrigerant
Refrigeration valve blockNew model
Wöhler MR 660 Refrigeration Valve Block
The MR 660 adds the ability to intervene in the refrigeration circuit to the SC 660 Smart Connect, for commissioning, maintenance and decommissioning. It has four connections: refrigerant cylinder or recovery machine, the refrigeration circuit, the SC 660, and a vacuum pump. Three separately controllable valves keep the flow path clear and safe, and a potential equalisation connection adds safety. With the precautions in its manual, it is compatible with flammable A2, A2L and A3 refrigerants.
- Four connections for cylinder, circuit, SC 660 and vacuum pump
- Three separately controllable valves
- Potential equalisation connection
- A2, A2L and A3 refrigerant compatible
Best for: Heat pump and AC commissioning with the SC 660
Two-stage vacuum pumpNew model
Wöhler VP 400 Vacuum Pump
Evacuation removes air and moisture from a refrigeration circuit before charging, preventing acid formation and poor performance. The VP 400 is a two-stage vacuum pump for all common refrigeration systems and heat pumps. An analogue vacuum gauge shows evacuation progress, an oil level indicator makes servicing easy, and a gas ballast valve reduces condensate drawn into the pump.
- Two-stage design
- Analogue vacuum gauge
- Oil level indicator
- Gas ballast valve
Best for: Evacuating AC and heat pump circuits before charging
Refrigerant recovery machineNew model
Wöhler REC 400 Recovery Machine
The REC 400 extracts refrigerant from a system so it can be repaired or decommissioned without venting to atmosphere. Guided operation with intelligent warnings, an illuminated display and an integrated pressure sensor with overpressure protection above 38.5 bar support safe use. Self PURGE mode prevents different refrigerants from mixing, and a push-pull method empties large systems quickly.
- Recovers A1, A2 and A2L refrigerants
- Overpressure protection above 38.5 bar
- Self PURGE mode prevents refrigerant mixing
- Push-pull method for large systems
Best for: Decommissioning and major repairs on refrigeration systems
Wöhler refrigerant leak detectors compared
← Scroll to see full table →
| RL 200 | RL 300 | |
|---|---|---|
| Standard | Developed to F-Gas Regulation | Fulfils DIN EN 14624:2020 and F-Gas Regulation |
| Sensitivity | 3 g/a | High sensitivity for smallest leaks |
| Display | Digital display | 11-level digital bar graph |
| Alarms | Not specified | Visual, acoustic and vibration, each switchable |
| Zeroing | Automatic | Automatic |
3 instruments
Wöhler water, dust and sound
Not every building services check is about gas or air temperature. Heating system water quality decides how quickly boilers and heat exchangers corrode or scale up, duct cleanliness decides whether a ventilation system needs cleaning, and noise decides whether a heat pump or fan installation is acceptable to neighbours. Wöhler makes a dedicated instrument for each.
Water analyserNew model
Wöhler WA 335 Water Analyser
Heating system water that is too hard or too conductive causes scale and corrosion, which shortens the life of boilers, heat pumps and heat exchangers. The WA 335 analyses the fill and system water so it can be treated correctly before it damages the plant, and gives the installer a recorded result to hand over with the system.
- Analyses heating system and fill water
- Supports correct water treatment
- Documents water quality at handover
Best for: Boiler and heat pump commissioning and servicing
Duct cleanliness testerNew model
Wöhler DTEST
The DTEST measures dust surface density inside ventilation ductwork, which is the objective way to decide whether a duct actually needs cleaning and to prove the result afterwards. Instead of arguing from a photograph, the contractor can show a cleanliness level before and after the work.
- Measures dust surface density in ducts
- Gives a measured cleanliness level
- Documents duct cleaning results
Best for: Ventilation hygiene inspections and cleaning contracts
Sound level meterNew model
Wöhler SP 22 Sound Level Meter
Heat pumps, extract fans and air-conditioning condensers all generate noise, and complaints about it are common where units sit close to a boundary or a bedroom window. The SP 22 measures sound pressure level so an installer can check a unit in place, compare positions and keep a record of what was measured.
- Sound pressure level measurement
- For heat pumps, fans and condensers
- Handheld and portable
Best for: Noise checks on outdoor units and plant
Using Wöhler instruments in South Africa
Wöhler designs its instruments to European standards. Most of them apply directly to South African work, but local conditions change how some tests are interpreted.
Altitude and combustion on the Highveld
Gauteng sits roughly 1,500 to 1,750 m above sea level, where air holds noticeably less oxygen per cubic metre than at the coast. Gas appliances set up at sea level can run fuel-rich inland, raising CO. An A 450 or A 550 reading of actual O₂ and CO in the flue is the reliable way to retune for local conditions.
LPG installations
LPG is widely used for cooking, water heating and space heating in South Africa, and installations fall under SANS 10087. The GS 220 is calibrated for LPG as well as methane, and the M 603 pressure-tests gas pipework, supporting leak checks by SAQCC Gas-registered practitioners before a certificate of conformity is issued.
Ventilation and indoor air quality
SANS 10400-O sets ventilation requirements for buildings. The DC 410 FLOW and FA 430 verify that installed systems deliver design airflow, while CO₂ monitors such as the CDL 210 show whether classrooms, offices and clinics are ventilated enough in practice.
Heat pumps and refrigerants
Heat pump water heaters and inverter AC units are now common, and many newer units often use flammable A2L or A3 refrigerants. The MR 660 is compatible with A2, A2L and A3 refrigerants, and the RL 300 meets DIN EN 14624:2020, helping refrigeration technicians work safely with these gases.
Wöhler inspection cameras available in our store
These Wöhler video endoscopes and inspection cameras are listed in the Ecotao online store. They are often used alongside measuring instruments to look inside flues, ducts, drains and cavities after a test points to a problem. See the full range on our Wöhler inspection systems page.
Frequently asked questions about Wöhler measuring instruments
Is it Woehler, Wöhler or Wohler?
All three refer to the same German manufacturer, Wöhler Technik GmbH of Bad Wünnenberg. The umlaut ö is written as oe in German when it cannot be typed, giving Woehler, while many English-language sites drop it and write Wohler. Product model names such as A 550 or RL 300 are the same under every spelling.
What does a flue gas analyser measure?
A flue gas analyser measures oxygen and carbon monoxide in the exhaust of a boiler, burner or stove, along with flue gas temperature and draught. From these it calculates carbon dioxide, excess air and combustion efficiency. The results show whether the appliance is burning safely and efficiently, and guide the adjustment of the air-fuel ratio.
Which Wöhler flue gas analyser should I choose: A 450, A 550 or A 550 Industrial?
Choose the A 450 for routine servicing where a compact, lower-cost analyser with full combustion functions is enough. Choose the A 550 if you also need the 4 Pa combustion air test and firewood moisture measurement from the same instrument. Choose the A 550 Industrial for emission measurement on larger plant, where you need sensors for SO₂, NO, NO₂ or NDIR CO₂ and flue gas velocity and flow measurement.
What is the 4 Pa test?
The 4 Pa test is a differential pressure test that confirms a room-air-dependent gas appliance is getting enough combustion air. It measures the pressure difference between the installation room and outdoors while extract fans and other air-consuming equipment are running. If the room is depressurised by more than 4 pascals, flue gases may spill back into the room. The Wöhler A 550 and DP 600 both perform this test.
What is the difference between the Wöhler GS 220 and GS 300?
The GS 220 is a gas sniffer calibrated for methane and LPG that detects the presence of combustible gas and guides you towards a leak with a staged LED bar and audible signal. The GS 300 is used once a leak is known to exist, to locate its exact position at joints, seals and appliance connections. Many technicians carry both.
Which Wöhler refrigerant leak detector meets DIN EN 14624?
The Wöhler RL 300 fulfils DIN EN 14624:2020, the European test standard for refrigerant leak detectors, and also meets F-Gas Regulation requirements. The RL 200 was developed to F-Gas Regulation requirements with a sensitivity of 3 g/a and suits routine maintenance checks.
How does altitude on the Highveld affect combustion testing?
Air is less dense at altitude, so at Johannesburg or Pretoria each cubic metre of air carries noticeably less oxygen than at the coast. A burner set up at sea level can run fuel-rich inland, producing more carbon monoxide and soot. A flue gas analyser reads the actual O₂ and CO in the exhaust, so the appliance can be retuned for local conditions rather than relying on factory settings.
What is the difference between the Wöhler FA 410 and FA 430?
Both are vane anemometers that measure air speed, temperature and humidity at supply and extract vents, and both come on their own or as a set with a funnel for volume flow at air terminals. The FA 430 adds CO₂ measurement, so one instrument covers both ventilation performance and indoor air quality. Choose the FA 410 for airflow work alone and the FA 430 where CO₂ matters too.
What CO₂ level means a room needs ventilating?
Germany's Federal Environment Agency classifies indoor CO₂ below 1,000 ppm as harmless, 1,000 to 2,000 ppm as elevated, and above 2,000 ppm as unacceptable. Wöhler CO₂ monitors such as the CDL 210 let you set an alarm threshold so occupants are prompted to open windows or increase ventilation before levels climb.
Can the Wöhler SC 660 be used on both water pipes and refrigeration systems?
Yes. The SC 660 measures pressure up to 60 bar and temperature, so it handles water pipe pressure tests with water, either alone or connected to the M 603 via Bluetooth. On refrigeration systems and heat pumps it connects directly to the service port to check operating pressure, superheat and subcooling without hoses. Combined with the MR 660 valve block, it also supports commissioning and decommissioning.
Do you supply Wöhler instruments outside South Africa?
Ecotao supplies test and measurement equipment across South Africa and to neighbouring countries including Namibia, Botswana, Zimbabwe, Mozambique, Lesotho and Eswatini. Contact the sales team with the model you need for availability and lead time to your location.
Need help choosing a Wöhler instrument?
Tell us what you need to test and we will recommend the right model and confirm availability and lead time. Wöhler instruments are supplied across South Africa and to Namibia, Botswana, Zimbabwe, Mozambique, Lesotho and Eswatini.
Head Office: +27 21 911 5835
Zak: 086 142 8716
Zaid: 082 390 3989
Email: sales@ecotao.co.za or aqua@ecotao.co.za