Sound Advice On Energy Saving

There are hundreds of clamp meters and multimeters to choose from if you’re in the market for a new instrument, though thankfully the choice can easily be narrowed to a handful of products if you know what features you need.

Recently you might have noticed certain products being referred to as ‘HVACr' suitable in your search. If you’re like me, you’ll have delved into specifications and features to identify why these products are isolated from the myriad of other digital multimeters and clamp meters available.

Well, let’s take a look at why!

Firstly, if you’re collared by the ‘HVACr’ tag on a clamp/multimeter, chances are you’re in one of the following trades: heating, ventilation, air conditioning or refrigeration. That’s what HVACr is the abbreviation of, right?

That much is obvious, but what application in this industry sector requires a specific HVACr instrument?

You’ll be familiar with flame supervision devices (FSDs) / flame failure devices (FFDs). If not, these devices (found inside gas appliances) are designed to stop flammable gases from entering the combustion chamber/burner of the appliance in the event of a flame failure.

One common type of FSD is an electrode probe that detects if a flame is present through the wizardry of flame rectification.

We’ll use a gas boiler as an example:

  • The PCB inside the boiler sends AC voltage (typically around 100V) to the flame rectification probe
  • When lit, the flame engulfs the rectification probe
  • The flame then acts as a conductor, changing the AC current to DC current in a process called rectification
  • The DC current then flows back through the earth/ground wire that is connected between the burner and the PCB
  • The PCB detects the DC current and stops sending AC voltage to the spark generator
  • If the PCB stops detecting DC current, it will stop delivering power to the gas valve, isolating gas from reaching the burner

If the PCB stops detecting DC current, it will stop delivering power to the gas valve, isolating gas from reaching the burner. Due to the very small amounts of DC current flowing from the burner to the PCB through the earth/ground wire, it is necessary to have an instrument that is capable of measuring very small amounts of DC current, with a high resolution (typically 0.1 microamps).

Therefore, instruments tagged ‘HVACr’ in their description will offer you the correct test range and resolution for the above.

The following instruments are listed on our website and are capable of the above:

Clamp Meters:
TPI 270 and TPI 275  HVACr Clamp Meter
Fluke 902FC HVACr Clamp Meter
Testo 770-2 and Testo 770-3 HVACr Clamp Meter
Amprobe ACD-14 Plus HVACr Clamp Meter

Fluke 116 True RMS Digital Multimeter

HVACr Clamp Meters

HVACr Digital Multimeters

For any further information about HVACr test and measurement equipment or calibration/servicing enquiries, we welcome your call on 0113 248 99 66 or enquiry through our online form.