Direct Unvented hot water Cylinder Question

16 Mar 2022
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United Kingdom
Hi There,

Wondered if anyone can help me work out how exactly my boiler works and how to use it efficiently to save money after some quite costly bills.

I have a Santon Premier Plus Unvented hot water system as well as a slimline Amptec Electroheat boiler (C400) alongside. I'm pretty sure the Santon heats the hot water for taps and showers etc, but not sure what exactly the Amptec is heating, perhaps the radiators?

Santon Premier
I believe this is an immersion heater with a top and bottom. The top being the booster, which should be off most of the time..? I have 2 immersion heater switches on the wall beside, with one connected to a mechanical boiler timer between it and the boiler (connecting into the lower part of the boiler). Should I being using that switch which is connected to the timer as my day to day?

Weirdly it looks like there's also an old digital timer close to the mechanical one which doesn't look like its cabled up. Maybe a older setup.

My meter has a day and night rate, so i'd be looking to have this running either all night or at certain periods, any recommendation on best times for that?

Amptec Electroheat
Does anyone have any clues as to what this would be used for? Heating only the towel rails and radiators? Does it heat water going into the Santon Premier? not sure.


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Anything specific? if i turn both boiler buttons off, the water gets colder over a period of a day or so. So im guessing the Amptec isnt feeding taps or showers directly.

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