Smart gas meter - registering use when no demand

mynameisboba

I downloaded the smart meter readings history from my current provider (Octopus) and noticed something odd.  From 15/11/2021 (when my previously dumb SMETS1 meter finally became smart again) it showed 0 m^3 of usage throughout the night when the heating was off (apart from particularly cold nights when the thermostat triggered the boiler).  However, after midnight on 20/01/2022, it started showing occasions through the night when a small but regular amount of gas use was recorded (0.01 m^3).  There doesn't seem to be a regular pattern of times or number of readings per night.  But every night since then, gas use has been recorded when there has been no demand (no heating, no hot taps used).

Before I start experimenting with my gas system, does anyone have ideas why this might be happening?

For technical context, I have a Worcester Greenstar i combi-boiler (electronic ignition - no pilot light), Hive Active Heating 2 wireless thermostat, Hive radiator valves.

pumas

How do you know a temperature drop hasn't fallen below the thermostat setting? Could you put the thermostat on 'holiday' for the period of hours previously recording use, so the boiler can't fire up?
(In the days of video cameras, I left it recording my freezer's noisy activities, don't suppose you could record the themostat screen or boiler noise?)

MWT

mynameisboba said:

However, after midnight on 20/01/2022, it started showing occasions through the night when a small but regular amount of gas use was recorded (0.01 m^3).  There doesn't seem to be a regular pattern of times or number of readings per night.  But every night since then, gas use has been recorded when there has been no demand (no heating, no hot taps used).

Before I start experimenting with my gas system, does anyone have ideas why this might be happening?

I would just go to a simple test, turn off the boiler over night and see what happens...

k_man

Does the Hive app show any boiler usage overnight in the heating history?

What is the thermostat set to overnight, and at what time does it switch to day temperatures?

mynameisboba

pumas said:

How do you know a temperature drop hasn't fallen below the thermostat setting? Could you put the thermostat on 'holiday' for the period of hours previously recording use, so the boiler can't fire up?
(In the days of video cameras, I left it recording my freezer's noisy activities, don't suppose you could record the themostat screen or boiler noise?)

The night time temp. settings on all thermostats is 7 °C and the Hive app allows you to track temperature variation.  The graphs show a continuous and steady fall of temperature throughout the night - at no time is there an uptick where it appears the heating has come on (see image).

I’ve got lots of ideas of how to experiment with the system to support a range of hypotheses, but was just wondering if anyone had experienced similar or could suggest likely reasons before I start.

mynameisboba

k_man said:

Does the Hive app show any boiler usage overnight in the heating history?

What is the thermostat set to overnight, and at what time does it switch to day temperatures?

The night time temp. settings on all thermostats is 7 °C and the Hive app allows you to track temperature variation.  The graphs show a continuous and steady fall of temperature throughout the night - at no time is there an uptick where it appears the heating has come on (see image 1).

I’ve also checked the boiler graphs - zero use is indicated (see image 2).

MWT

mynameisboba said:

I’ve got lots of ideas of how to experiment with the system to support a range of hypotheses, but was just wondering if anyone had experienced similar or could suggest likely reasons before I start.

I wouldn't get too creative, just a simple leak-check for safety to begin with.

Just turn off the boiler (assuming no other equipment using gas?)and go read the gas meter, leave it over night, read meter again.

Do read the actual meter not the IHD as the IHD is only updated every 30 mins so.