A dumb question on conventional heating

[joulevaillant]

Hi, I have a conventional heating system consisting of Vaillant ECOfit (vented) and a Joule Cyclone air indirect (unvented) boilers. I had observed last winter that the Vaillant boiler was just used to heat tap water (though it has controls to set temperature for radiators as well) and Joule for central heating. But after the engineer's visit in September, I see that the Vaillant boiler is getting used for central heating. I am not sure if the Joule boiler is being used at all now. Both used gas for heating.
Question:
1. As it was not the case last year, should I be concerned?
3. Using just the Vaillant boiler increases my gas bill (I feel it does)?
2. What should I do to switch the central heating from vaillant to Joule boiler?

PS: The gas engineer (and the company) who attended are unresponsive.
Greatly appreciate any help on this.

 

[EvilDrPorkChop]

The Vaillant boiler (The energy source) heats the water in the radiators, and heats up the Hot Water in the Joule Cylinder.

The Joule Cylinder stores the Hot Water (That comes out your taps).

Hope that's a simple enough explanation.

 

[joulevaillant]

The Vaillant boiler (The energy source) heats the water in the radiators, and heats up the Hot Water in the Joule Cylinder.

The Joule Cylinder stores the Hot Water (That comes out your taps).

Hope that's a simple enough explanation.

Thanks for the response.
You mean Joule just stores the hotwater coming from Vaillant and has no active heating function? Because I remember that the Vaillant boiler was not even switching ON when I used to switched OFF tap water heating. So, I thought there is some mechanism in the system to ensure that Vaillant just heats tap and leave it to Joule for the central heating to ensure efficiency.

 

[EvilDrPorkChop]

Yep. The Joule stores Hot Water that comes out of your Hot water taps. The Vaillant heats that tank for your Hot water. The Vaillant will also heat the radiators too.

Depending on your time controls, the 'Tap' function on the Vaillant won't do anything. The radiator setting sets the temperature of the water coming out the boiler.

You will also have a back up immersion heater powered by electric on the Joule. Should your Vaillant fail then you can use the Electric Immersion to heat your hot water up (This is only your hot water not the radiators)

The Joule tank has nothing to do with your radiators.

 

[joulevaillant]

Yep. The Joule stores Hot Water that comes out of your Hot water taps. The Vaillant heats that tank for your Hot water. The Vaillant will also heat the radiators too.

Depending on your time controls, the 'Tap' function on the Vaillant won't do anything. The radiator setting sets the temperature of the water coming out the boiler.

You will also have a back up immersion heater powered by electric on the Joule. Should your Vaillant fail then you can use the Electric Immersion to heat your hot water up (This is only your hot water not the radiators)

The Joule tank has nothing to do with your radiators.

Thanks so much. It's clear now.
Looking at my energy meter (~£13-£15 per day with continuous heating use), I was hoping there is a better and efficient way of heating. But looks like this cost is the norm and I just need to pay up.

 

[Gasmk1]

What controls do you use you could get the weather compensation fitted this would be more economical

 

[EvilDrPorkChop]

What controls do you use you could get the weather compensation fitted this would be more economical

Don't think you want to complicate things any more than they already are