Is It O.K. To Leave Hot Water on 24/7 With a Combi?

[boozercruiser]

Hello. Some of you may be aware that we have recently had a brand new Worcester Greenstar Heatslave 18/25kW Oil Condensing Combi Boiler installed.

My Wife and I use Hot Water mainly in the morning to have a Shower, do the Dishes, Wash Hands and then in the evening for about the same reasons.

We tend to leave the Boiler setting on the lowest setting of 1 which gives a temperature of around 47 which serves most of our purposes.

Would there be an awful lot of extra Oil used if the Boiler where just left on, or is it best for the timer be set to come on just before the periods of likely use?

We haven't needed to use the Heating at all yet.

Thank you for any advice and input.

 

[Deleted member 105431]

with a combi the boiler is only running and burning fuel when a hot tap is running or the heating is on. (exception being a preheat/warmstart function) the rest of the time it is dormant and not using any fuel at all (except very small amout of electricity).

 

[simond]

The Oil heatslave has a substantial internal HW cylinder buffer store and the OP is questioning whether it is prudent to time this.

The answer is, assuming you have the optional two channel Drayton sourced facia timer, yes. If there are significantly long periods of nil demand then programme it off for those times, and you will save some energy.

In contrast, a conventional GAS combi usually has a preheat capacity of less than 2 litres and therefore heatlosses are less significant, some manufacturers (eg; Vaillant) offer ways of timing this (via VRT360, or VRC 430 controllers).

 

[boozercruiser]

"The Oil heatslave has a substantial internal HW cylinder buffer store and the OP is questioning whether it is prudent to time this".

Yes, according to the Manual the HW cylinderbuffer store (obviously very well insulated) actually holds 69 Litres of Water. I am thinking that perhaps the Boiler is coming on occasionally to keep the Water at the Lowest setting of 47 Degrees, which is still quite hot.

I realize of course that say the Boiler is set to 'Off' for the Water for say 7 hours then the water will have cooled somewhat and then will have to use more Oil to bring it back to temperature.

With the high cost of oil right now (We recently spent £955 for 1500 Litres) then we would like to get it right.

Though it does seem a bit like 'Swings and Roundabouts' to me

Thank you for any advice given.

 

[rssteve]

it will always cost more to keep it up to temperature than to let it cool and then reheat several hours later.