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Technical Bulletin 112

Developed with industry

Obtaining meter index readings for gas rating on electronic and smart gas meters  
Date issued: 7 December 2017

This Technical Bulletin has been developed to assist Gas Safe registered businesses/ engineers undertaking gas rate checks on all currently known electronic gas meters (including ‘SMART’ meters).

Note: This version of Technical Bulletin (TB) 112 replaces the version originally published on 26 August 2016, which is now withdrawn. This version has been amended to revise the procedure for gas rating using the Itron RF1 Sv ZB meter (Appendix 5) and, where appropriate, revised to ensure that it remains both current and relevant.

The complexities of the current range of electronic gas meters have proven problematic when attempting to gas rate an appliance because the gas meter displays do not immediately show the volume of gas passed by the meter. Each meter manufacturer has developed its own procedure to enable the gas rate process to be undertaken.

There a number of different manufacturers of electronic gas meters (including smart meters) now supplying gas meters to UK gas suppliers. In this Bulletin, each manufacturer’s information is contained within individual appendices.

The electronic meters covered by this Bulletin are:

  • Landis+Gyr – see Appendix 1
  • Secure Meters (UK) formerly PRI – see Appendix 2
  • Elster – see Appendix 3
  • Flonidan – see Appendix 4
  • Itron RF1 Sv ZB – see Appendix 5.

These will be added to over time, as more information becomes available.

Appendix 5: Itron RF1 Sv ZB
This appendix details a procedure, confirmed by Itron, that will need to be followed in order to carry out successful gas rating of appliances with this type of gas meter.


Gas rating an appliance

1. When gas rating an appliance, the appliance should be running as per the manufacturer’s instructions.

2. Press any of the two buttons on the front of the meter (orange or blue). The meter will wake up and start to show the incrementing gas flow on screen “A0”.

Note 1: If screen “A0” is not displaying this can be scrolled to by short-pressing the orange button.

3. Within 30 seconds of waking the meter and at the next increment of the index while gas is flowing, start the two-minute test and note the meter reading index at the start of the test.

4. After 30 seconds the index will go blank but the meter is still measuring the flow taken during the test.

5. Within 30 seconds of the end of the two-minute (120 seconds) test period, press any of the two buttons (orange or blue) to re-awaken the display. This will show the updated meter index. When two minutes are complete, make a note of the final meter index reading.

Note 2: If screen “A0” is not displaying, this can be scrolled to by short-pressing the orange button.

6. Calculate the gas rate over the two-minute period by subtracting the initial reading from the final reading. Then calculate the hourly gas rate of the appliance using the normal method.

Prepayment mode
In prepayment mode, press any of the two buttons (orange or blue) to wake the display.

The display sequence will start with “J0”. Press the blue button twice to navigate to “J2”, which is the Gas Volume Index. Make sure that there is at least two minutes’ worth of emergency credit available on the meter or the gas rate test cannot be completed.

Part of the valve opening cycle includes a leakage test, so wait for this internal test to complete before any appliance is turned on. Failure to do this will result in the immediate closure of the internal valve.

Once the credit is available, the valve is open and the internal leakage test has been accomplished, the same procedure as the credit mode can be applied.

Note 1: For details of current gas safety legislation, building legislation and industry standards for the geographical areas covered by Gas Safe Register, see the Legislative, Normative and Informative Documents List by logging into your online account at

Note 2: For general information about the process behind the development of Gas Safe Register Technical Bulletins and the expectations for all stakeholders, see Technical Bulletin 1000 by logging into your online account at

Download Technical Bulletin 112 here

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