Please help! Santon Premier Plus unvented boiler 210l

SamSiSox

I think I will probably sound stupid but I cannot work out our boiler system. 

We have a gas boiler central heating. We then have a Santon Premier Plus unvented tank on the 2nd floor. Next to it is the timer setting for hot water as well as heating. We have 3 showers. 2 on the 2nd floor and 1 on the top. 

Between April and Oct the heating goes off completely but I always kept the hot water coming on in the mornings. I have always assumed this was also heated via gas. 

Last year I turned off the hot water timer when we went on holiday at Easter, and I forgot to turn it back on. I didn’t realise it was off until October when I went to turn the heating on for winter because we were still getting hot water. We still run out of hot water in the same way when we all have showers - in the same way when I had the hot water on a timer coming on I. The morning.

I tested it yesterday - the gas boiler was not fired up when I turned the hot water on. So now that makes me think it is electric but I was convinced the gas boiler came on previously. Now I’m not sure. I thought my gas bill is a lot smaller in summer now because it’s only on for the cooker so I don’t understand what is happening. 

So how are we still getting hot water on demand, but it still ‘runs out’ if the hot water tank is not being heated regularly? Or how is it being heated? I just want to be most efficient with energy. 

I’ve read these boilers have an electric back up if the gas is not working but how is it heating the water/when. Because if the water is heated on demand, surely it wouldn’t run out? 

As I said I know this might sound ridiculous but if anyone could help I would appreciate it. 

TadleyBaggie

Sounds like you have the hot water tank's immersion heater on 24/7. Even with it on all the time, it's not hard to drain it of hot water which then takes a hour or so to reheat.

SamSiSox

Thank you for responding. Oh I see. So if I set the timer will the 24/7 aspect be overridden?

TadleyBaggie

Immersion heaters, in my experience, don't have timers (although they could). They are usually on or off. In my house mine is never switched on, as I allow the central heating boiler to to heat the water.

The immersion heater should have a thermostat, so if the gas boiler is keeping the water hot the immersion heater shouldn't be doing much.

macman

SamSiSox said:

Thank you for responding. Oh I see. So if I set the timer will the 24/7 aspect be overridden?

Just switch it off at the isolator. The only time you should ever need to use it is an an emergency backup if your boiler is out of service.
It's costing you 350% more to power your DHW with electricity than gas.

Rodders53

There will be an immersion heater underneath a (plastic) cover near the bottom of that HW cylinder. The thermostat adjuster(s) for immersion and gas heating will likely be under there too.

A fairly fat heat-resistant rubber cable (usually white) will run from there to a mains switch nearby - may have a 13A fuse in the switchplate (or, ideally not). It may have a red neon 'ON' indicator lamp. Turn that off and label it 'Immersion heater' emergency use only!!  In the main consumer unit there will likely be a 16A circuit breaker labelled water heater.  Switch off there as well to ensure no-one accidentally turns it back on.

There may be another similar switch that turns off the gas boiler/heating controls in that area (likely close to the controller you mention).

The immersion needs turning off completely otherwise it will 'assist' the gas boiler to heat the water every time water needs reheating (and it may even have a different, higher, temperature setting than for the gas boiler).

If in doubt take a few photos of the airing cupboard and controls / mains switches you can find and someone will be able to identify the right ones.

SamSiSox

Thank you! So done that. Any idea then how I get my boiler to turn on when I want my the water heating as there is no response when I select the hot water button to boost or constant? The boiler does come on when selecting the heating button to boost or constant. 

SamSiSox

Rodders53 said:

There will be an immersion heater underneath a (plastic) cover near the bottom of that HW cylinder. The thermostat adjuster(s) for immersion and gas heating will likely be under there too.

A fairly fat heat-resistant rubber cable (usually white) will run from there to a mains switch nearby - may have a 13A fuse in the switchplate (or, ideally not). It may have a red neon 'ON' indicator lamp. Turn that off and label it 'Immersion heater' emergency use only!!  In the main consumer unit there will likely be a 16A circuit breaker labelled water heater.  Switch off there as well to ensure no-one accidentally turns it back on.

There may be another similar switch that turns off the gas boiler/heating controls in that area (likely close to the controller you mention).

The immersion needs turning off completely otherwise it will 'assist' the gas boiler to heat the water every time water needs reheating (and it may even have a different, higher, temperature setting than for the gas boiler).

If in doubt take a few photos of the airing cupboard and controls / mains switches you can find and someone will be able to identify the right ones.

Ah ok, thank you. Turned off the switch in the cupboard. and the circuit breaker. It made a funny swish noise in the water storage area. 

I selected the button on the hot water to boost. Still no response from the boiler? 

SamSiSox

This is the switch I have now turned off. The controls are above which I have turn on. 

And turned the circuit breaker off. I cannot find any more relevant switches and the boiler is not coming on?

macman

The boiler would only fire up if the hot water in the tank was already below the temp set on the tank 'stat.
Post a pic of the boiler or programmer controls.
Are you sure you didn't turn off the boiler power at the CU as well? Is the immersion on a dedicated circuit? You don't need to turn the immersion off at the CU, just at the isolator.

SamSiSox

No activty at the boiler.