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DIRK053
Rank 1
Nov 21, 2024 2:48 PM UTC
Solved

Why does my boiler use energy overnight?

Afternoon all

 

We have just moved into a new house with a Combi boiler, previously house had a standard boiler & storage tank.

Have noticed over the last week or so that the boiler ticks in a lot even when it is off

(not manually activated, no timer and the thermostat is set lower than the ccurrent room temp)

Having looked at some of the overnight events. I see we are using between 3.5/4kw per hour.

does this seem normal?

 

BPLightlog
BPLightlogBest Answer
Super User
Nov 22, 2024 8:24 AM UTC

Just a quick thought ​@DIRK053 as I saw something similar to your overnight usage recently with a combi set with weather compensation. 

Overnight, the heating was set at 15 deg and although the internal temperature was higher, the calculations in the boiler determined that there was a need to maintain some heat even though the thermostat wasn’t calling for it. You can see the estimated kWh effect in the graph which continued until the main heating programme kicked back in just before 6am. 
I don’t like weather compensation personally as it does things like this which can be difficult to understand. 

Bring me Sunshine ~ E&E {Solar PV, Battery Storage, EV, ASHP and Home Assistant automation}
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7 replies

BPLightlog
Super User
BPLightlogSuper User
Super User
Nov 21, 2024 3:06 PM UTC

It will depend on the set up ​@DIRK053 

Some have various sensors for outside temperature, weather compensation and a winter mode setting so you really need to try to check what is set currently. 
If you don’t have a manual, there are several available if you know the exact make and model.

It could even be something on the hot water if it is set to pre heat to reduce time to get hot water at the tap

Bring me Sunshine ~ E&E {Solar PV, Battery Storage, EV, ASHP and Home Assistant automation}
Rank 1
DIRK053Author
Rank 1
Nov 21, 2024 3:13 PM UTC

Thanks for the reply

Nukecad
Super User
NukecadSuper User
Super User
Nov 21, 2024 3:27 PM UTC

My Vailant combi boiler runs a ‘tickover’ and self-test at about 02:00 each night.

It only lasts a minute or so, fires the burner and runs the CH pump.

That makes sure that if the heating has been turned off (eg. for summer) then the parts are given a turnover/workout at least once a day so that they don't seize up from being idle for an extended time.

Out of beer error >>>> Recovering memory.
    Chris_OVO
    Community Manager
    Chris_OVO
    Community Manager
    Nov 21, 2024 4:30 PM UTC

    Hey ​@DIRK053,

    Welcome to the community! 

     

    I see a couple of our wonderful members have already stopped by with some advice. I’ll add some of my own 😄

    My boiler has frost protection and as it’s currently below freezing in Scotland I can hear it circulating the system overnight to prevent the system from freezing and causing damage. It would be worth looking for a manual either in person or online so you can check your settings as ​@BPLightlog suggested. 

     

    Hopefully this helps! 

    Renewable energy jokes never get old.
      Newcomer
      krazy391
      Newcomer
      Nov 21, 2024 8:56 PM UTC

      Make sure your boiler isn’t set to comfort mode (or equivalent) so it’s not keeping a small tank of hot water inside all day and night

        BPLightlog
        Super User
        BPLightlogSuper UserBest Answer
        Super User
        Nov 22, 2024 8:24 AM UTC

        Just a quick thought ​@DIRK053 as I saw something similar to your overnight usage recently with a combi set with weather compensation. 

        Overnight, the heating was set at 15 deg and although the internal temperature was higher, the calculations in the boiler determined that there was a need to maintain some heat even though the thermostat wasn’t calling for it. You can see the estimated kWh effect in the graph which continued until the main heating programme kicked back in just before 6am. 
        I don’t like weather compensation personally as it does things like this which can be difficult to understand. 

        Bring me Sunshine ~ E&E {Solar PV, Battery Storage, EV, ASHP and Home Assistant automation}
          Rank 1
          DIRK053Author
          Rank 1
          Dec 3, 2024 11:31 AM UTC

          Thanks for the replies, will have a look at this looking at my smart metere usage, I worked out my extra usage overnight and when we were out was  almost 35% in Nov.

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