gas reading anomaly

Did the heating kick in overnight?

I noticed mine do that one day a month or so ago. When I checked the boiler I found that the mechanical timer had broken (sometime over the summer) and had stopped during an ‘On’ period.

That meant it was stuck at “On’ for 24 hours a day, and so when the temperature dropped at night the boiler fired up.
(I got a new timer).

Another possibility is if you have had a power cut, or the power has been off for some other reason*, and the timer was stopped so now shows the wrong time, so could come on during the night.

*I recently also had EICR testing done which means turning the power on and off several times, so had to reset my new timer after that.

Check your boiler timer to make sure it is working and is set correctly.

My gas boiler for heating is, in reality, on every day from 6.30 am to 11pm. In addition to the timer, we have the system thermostat and the individual room thermostatic radiator valves that control when the heating actually does fire up. It has, in the last week come on three times at 6.30 am, for a short period. 

Thank you all for replying.  Just had a new boiler installed.  Have not had heating on yet and won’t be putting it on a timer, only as and when I want it on.  The heating temp is below what room temp is so won’t come on.   Have only been using a boost for hot water during the morning which is registering on my usage that is when I notice that 1.5 hours of gas had shown up at 5am.  This is the first time this has happened as I check the usage daily.

Could you tell us what make/model your new boiler is?

You say you used a heating boost, which says that it isn't a combi boiler but that you have a hot water tank.

If we know just what it is then we could look up the manual to see the controls and how it works. Which should avoid asking lots of questions.

It's not clear just what you mean by:

“ The heating temp is below what room temp is so won’t come on. “

Which “heating temp” ? The thermostat setting? or the radiator flow setting?

TBH we often get questions about strange usage over night (both electricity and gas) and it almost always turns out to be a setting error, a forgotten setting, or a forgotten heater that is on a thermostatic control. (Like an oil filled electric patio heater).

If  it was simply a cold night where you are, and the room temp dropped overnight, then from what you have described the heating could have come on.

Another alternative as you appear to have a water tank would be if the tank cooled down overnight and the tank thermostat signalled the boiler to heat it up again.

Most modern boilers (such as Worcester Bosch, Vaillant, and Ideal) have an internal sensor that fires up the burner at roughly 5°C (and runs the pump around 8°C) to stop internal components from freezing. Mine (a Vaillant) has been coming on as it is in an unheated garage. I noticed that it fired up around 11.15pm for a few minutes yesterday evening.

Hey ​@Unknownuser2 

I’m glad to see a few of our community members have already stopped by with some helpful advice here. 

It might be worth checking if that feature Bendog mentioned is something your boiler is doing to keep it up to a certain temperature even when it’s not in use to prevent freezing or faults to occur as a result of things like freezing.

Hey ​@Unknownuser2,

I wanted to share something about my Hive thermostat. It has a handy frost protection mode that kicks in the heating on those extra chilly days, helping to keep the pipes from freezing. If you have a similar setup, like a Nest or Tado, you might want to check if they have something like this too!

I’ve attached an article I found that gives a little more insight into this feature. Hope it helps!

https://support.hivehome.com/portal/app/portlets/results/viewsolution.jsp?solutionid=240315185739873

Your Ideal Logic+ Heat boiler does have a frost protection feature - so it may well be that which fired up and used the gas overnight.

From page 4 of the boiler’s User Manual

BOILER FROST PROTECTION

The boiler is fitted with frost protection that operates in all
modes, provided the power supply to the boiler is always
turned on. If the water in the boiler falls below 5ºC, the frost
protection will activate and run the boiler to avoid freezing.
The process does not guarantee that all other parts of the
system will be protected.

If a system frost thermostat has been installed, the boiler must
be set in winter mode, [ Ready or On ] for the frost protection to run.