Boilermate III behaviour & energy usage

I recently moved into a new place and have had some massive electricity bills.

The house seems to use about 9kw of electricity a day when we are not even there
which seems insane.

There are two boilers:
- ideal Logic
- Gledhill Boilermate 3

The Boilermate has a honeywell timer to control heating on/off but there seems to be no means to control hot water which is always available.


I recently got an energy monitor to try figure out the problem. This is what I found...

When switched off on the honeywell control the Boilermate still operates for 3-4 minutes between 1 and 3 times an hour. I know it’s the boiler as I can hear it rumble when the energy monitor has high readings.

According to the monitor it’s using 3kw during these times(I presume keeping hot water available).
That’s about what it reads when I boil the kettle.
It also runs at that kw rate for prolonged periods whenever hot water is used.


The base reading from the energy monitor reads anywhere between 125 and 175w. That’s with everything switched off except fridge, cooker, boilers (set to off), alarm and smoke detectors . About 80w of this is the fridge and 5w for the cooker. (I haven’t switched of the fuse for the house alarm or the smoke detectors as I’m paranoid of triggering them!).


So I think the boilermate is the culprit but it would be great to get some advice on:
- whether the boiler energy use seems excessively high and is the likely culprit
- whether this is normal behaviour for a boilermate or sounds faulty
- any tips on resolving

Any advice really appreciated.

Thanks!

Status update :

I discovered the immersion heater had been switched on all the time so I'm monitoring the running and energy consumption since turning it off.

I turned on the central heating via honeywell and the logic boiler fired up (burner indicator on) and the heating appears to be working ok.

The energy monitor has not spiked in the past few hours since switching off the immersion heater.


Not that I noticed it myself until attempting to troubleshoot our massive bills and getting some helpful direction here but it seems really odd that the previous tenants would have left the immersion heater set on by default.

Immersion heater is only for emergency use in the case that the gas boiler has failed - it will heat the store so that you get hot water and heating while the gas boiler is being repaired.  The immersion should normally be OFF.  My neighbour had hers on for years until I pointed out that she was wasting money.

By the way, the BoilerMate III is not a boiler, it's a thermal store.