testo 300

Built for a Day of Service Calls

The testo 300 is designed for technicians doing heating system work several times a day. Everything about it is aimed at getting through jobs faster, from the moment it comes out of the case to the moment the report is sent.

In standby mode, it’s ready to measure at the touch of a button, with no waiting before the first reading of the next job. The 5 inch HD touchscreen responds like a smartphone and shows all the system’s values straight away, and clearly structured menus for heating applications guide you through each job.

Zeroing Without Pulling the Probe

A flue gas analyser has to zero its sensors before it can measure. On most instruments, that means removing the probe from the flue, waiting for zeroing to finish, then putting it back. On a job with several measurements, it happens repeatedly.

The top testo 300 Longlife models, with 15,000 ppm and 30,000 ppm CO sensors, zero with the probe still in the flue gas. The probe stays where it is, and the measurement continues sooner. On a day with six or eight service calls, that adds up to real time.

The Models

The practical differences are the CO range, whether the sensors are Longlife, whether an NO sensor can be added for NOx measurement, and whether zeroing works with the probe in the flue.

Carbon Monoxide Range, and What Thirty Thousand Means

The CO sensor options run from 0 to 4,000 ppm, through 8,000 and 15,000, up to 0 to 30,000 ppm.

Hydrogen compensation is worth understanding. CO sensors respond to hydrogen as well as carbon monoxide, and incomplete combustion produces both. An uncompensated sensor reads high because it counts hydrogen as CO, which on a poorly burning appliance can be a significant error. A compensated sensor corrects for it.

The 15,000 and 30,000 ppm ranges use integrated fresh air dilution. That lets the instrument measure a high concentration without exposing the sensor to it, extending sensor life on appliances that run dirty. Automatic CO and NO sensor protection adds to that.

Six Year Sensors

Longlife sensors have a service life of up to six years, depending on the load, and are designed for intensive use several times a day. Testo says at least one sensor replacement is saved over a normal working life.

That’s a cost of ownership argument rather than a performance one, and for a contractor doing this work daily, it’s what justifies the Longlife models. Sensor warranties of 2 or 4 years are available, depending on the sensor chosen.

Documentation on Site

A heating service visit generates paperwork, and the traditional route is a reading written on a pad, typed up later and emailed the next day.

The testo 300 creates the documentation on site. Measurement reports include readings, customer and heating system details, comments, the customer’s signature and your company logo, and are emailed straight away over WiFi. All PDF reports are saved in the instrument too. A Bluetooth printer is available where a customer wants a printout, and testo EasyHeat software handles records on a PC.

The value isn’t just convenience. The number in the report is the number the instrument measured, without a copying step where errors creep in.

Probes

One multi function handle takes a range of probe shafts, connected through a universal plug. Probes from the testo 320, testo 330 and testo 330 LL can be used with the testo 300 as well, and new probes with USB-C connection are available for flow and return temperature and ambient CO measurement.

Where It Sits in the Range

The testo 310 II is the simpler instrument, with two sensors and a 7 line display rather than a touchscreen. For occasional boiler work, it’s enough, and it costs less.

The testo 300 is for technicians doing this work daily. The touchscreen, standby readiness, on site documentation and, on the Longlife models, the six year sensors and in flue zeroing are all aimed at getting more jobs done.

The testo 340 is the industrial instrument, adding nitrogen dioxide and sulphur dioxide, dilution of all sensors and mass emission calculation. If the work is engine tuning or emissions reporting rather than heating systems, that’s the tier.

Where It’s Used

Domestic and commercial boiler servicing. Heating system commissioning. Hot water plant. Apartment and residential building plant rooms. Hospitals, aged care and hotel heating plant. Schools and universities. Commercial kitchens and laundries. Swimming pool and leisure centre heating. Gas appliance servicing. Boiler room ambient CO checks.