Reading other forums like digital spy, it seems gas meters are never mains powered and instead have long life batteries. The gas meter is connected to a mains powered  hub by Zigbee radio which has a very low power consumption. The hub then handles comms to the IHD, the smart electric meter and the energy provider. Some users are reporting battery failures and sadly this turns off the gas and needs an engineer to install a new battery. The gas meters also have buttons which can be used by consumers to show readings. Usually the screen is blank and has to be woken up by pressing a button. Different meters have different button layouts. The consumer only has to use these if the IHD has failed or the meter is in ‘dumb’ mode. 

So, living with a smart gas meter is a bit different to a smart electric meter, this explains why so many IHD users say their gas readings are not up to date, because to conserve power the gas meter only talks to the hub at certain intervals, and is not in real time contact. 

The 10 second timeout I referred to in my previous answer relates only to the display and backlight.

The meter itself wakes up (without the display coming on) every 30 minutes and transmits the current reading to the electricity meter.  As you say, the electricity meter then handles the communication to the IHD and the upstream energy provider.

It does say in the insstructions left by Scottish Power that the gas meter reading on the IHD only updates every 30 minutes, unlike the electric usage which refreshes every 10 seconds.

The instructions for the IHD can be found here.  Note specifically the panel titled "View energy use across a time frame" where it says:

"Please note, your gas meter updates the In-Home display every half an hour, whereas the electricity is updated every 10 seconds."

To answer the second part of the OPs question regarding the IHD not showing any readings, if that is the case then it's likely that the gas meter hasn't been paired correctly and this will need an installer visit to correct.  It's disappointing to hear you've only just turned on the display having had the meters fitted "recently".  If the installer had done their job properly then the IHD should have been turned on, setup, and demonstrated during the installation at which point it would have been obvious the gas meter wasn't updating.

Have had smart meters installed since last September.  IHD has never worked properly except for a day after it was installed.  To date same situation persists and in addition, whereas I was able to see meter readings on my phone app till a couple of weeks ago, this function now is blank, I have spoken to many people at SP and am told various answers.  The latest was that they were aware of no meter readings appearing on app and this would be rectified in a couple of months.  They said they were able to receive my gas and electric meter readings but if I want to check myself, have to read meters manually and being a bit elderly this exercise was to be taken over by the Smart Meters.  I was told last year that my meters would be replaced early this year as the meters I have are the first version and SP know they dont work effeciently.  Needless to say I am still waiting.

My smart meter has not worked from day 1.   How about a replacement.

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