Help with my heating settings?

[Kotek Besar]

Hi folks. I'm new here! :hurray:

So I was just looking for someone in the know to quickly advise on something.

I have a system boiler (Ideal Logic Heat 15) which is about 2 years old. I have Hive Active Heating. Normally I set the hot water to heat for 30 minutes in the morning (so we can have our showers) and then for 30 minutes in the afternoon (so the children can have their baths after school). This generally gives us just enough hot water.

Sometimes around midday, however, I need to "boost" the hot water in Hive - basically this heats the water for an additional 30 minutes. That's ok, but here's my real question:

Just yesterday I turned up the dial on the boiler, and also on the hot water tank in the airing cupboard. This has made the hot water hotter. It meant that the 30 minutes hot water heating in the morning lasted not only for our showers but also throughout the day and I didn't need to "boost" for another 30 minutes. Obviously, this is because the temperature of the hot water coming out of the shower is higher and so we need less to mix it with the cold water in order to get the desired temperature. So, question is, is this the most cost saving or not?

Please see attached pics of my current settings. Note that I have the boiler turned up slightly more than the "eco" setting which, up until yesterday, is what it's been on for the past 2 years. Also, the hot water tank in the airing cupboard is now on about 74 degrees C, previously that was on about 65 degrees.

So, have I don't the right thing or should I brace myself for a huge gas bill?

 

[Riley]

You don't want the temperature of the hot water cylinder so hot as it will promote scale

 

[Kotek Besar]

You don't want the temperature of the hot water cylinder so hot as it will promote scale

Thank you. I will turn it down now. Back down to 65 degrees C, or what would you suggest?

 

[Riley]

I know others will probably say differently but I always say somewhere between 55 and 65 below 55 you run the risk of legionella

 

[Last Plumber]

I haven't seen your house/system/boilers or tanks. I'm presuming you have an unvented cylinder ?
I would set the cylinder to 60 deg C personally, ( cylinder stat )
The timing is your choice of course. Everyone sees it different. Some customers do what you do, I personally leave my own DHW on 24/7.

what have you got your system boiler set to ?
you say hot water is 74 degrees, so you must have boiler at max ?
If so, it won't be condensing once the return passes 53 degrees ( roughly, other factors involved ), after that temp the boiler efficiency drops off quite a lot.

You would be better getting a good, experienced heating engineer to call in the flesh.
Next time the boiler service is due, ask him or her to look it over and advise you on the best way of running it.

 

[Kotek Besar]

Thanks guys. I'll set the tank to 60 degrees C then.

Can I ask though, what does this actually do? I mean, what is it's function?

And, in relation to the boiler, she's currently on slightly hotter than "eco". So this obviously heats cold water and then sends hot water to the tank, ready for use, right? So if the boiler sends water that is hotter than 60 degrees, does the tank just hold the hot water and keeps it, heating it up again for it's not used and drop below 60 degrees? Conversely, if I were to set the boiler dial down to less than eco, for example, and the boiler then heats the water to, say, 50 degrees, then when the tank receives this will it heat it up to 60 degrees?

Sorry if all this seems silly to you guys - I've never really understood how the system works properly, and I'd like to. Pics now attached by the way.

 

[Last Plumber]

Simplest way of explaining it is :-
Cylinder is like giant kettle but instead of electric element it has a coil of tube.
The coil of tube is heated by water from boiler ( same as in rads) water goes through coil and back to boiler, round and round
Water Picks up heat from boiler, loses heat from coil.
Coil, like kettle element is submerged in different water ( that goes to taps).
Coil loses heat, tap water gains heat.
Your cylinder stat tells boiler, when enough is enough, boiler goes off.

I hope that was in no way patronising or too simplistic. I'm in a rush to get back to work but thought it might help you understand a bit more.

 

[Kotek Besar]

No that's brilliant, thank you very much for taking the time to explain all that to me, expecially when you're busy working. I really had no idea. :smart:

 

[Kotek Besar]

I see you're in Lancashire by the way. I'm in North Barnsley (nearly Wakefield). Too far for you for a service?

 

[Thedeester1]

I haven't seen your house/system/boilers or tanks. I'm presuming you have an unvented cylinder ?
I would set the cylinder to 60 deg C personally, ( cylinder stat )
The timing is your choice of course. Everyone sees it different. Some customers do what you do, I personally leave my own DHW on 24/7.

what have you got your system boiler set to ?
you say hot water is 74 degrees, so you must have boiler at max ?
If so, it won't be condensing once the return passes 53 degrees ( roughly, other factors involved ), after that temp the boiler efficiency drops off quite a lot.

You would be better getting a good, experienced heating engineer to call in the flesh.
Next time the boiler service is due, ask him or her to look it over and advise you on the best way of running it.

Isnt the right thing to do is set the boiler stat less than the tank stat? That way the tank stat will turn off the boiler but the pump will still circulate the heated water? If you then balance the radiators for a 12 degree loss across them you have the most efficient system?

 

[shyguy2005]

Boiler stat should always be higher than cylinder stat.

 

[Last Plumber]

Isnt the right thing to do is set the boiler stat less than the tank stat? That way the tank stat will turn off the boiler but the pump will still circulate the heated water? If you then balance the radiators for a 12 degree loss across them you have the most efficient system?

If the boiler stat is lower than the tank stat the tank will never reach the temp that the tank stat is set to. So the boiler will be on as long as the time clock says. So no, I wouldn't do that.

 

[Last Plumber]

I see you're in Lancashire by the way. I'm in North Barnsley (nearly Wakefield). Too far for you for a service?

It is really. Better to put post code in gas safe website to find someone nearer really.
Thanks for asking though

 

[joni os]

Boiler stat should always be higher than cylinder stat.

To heat water in DHW cylinder to a given temperature the water in the coil. ie water passing through boiler needs to be at higher temperature Water in cylinder stratifies, hot water rising, so with cylinder stat positioned in the lower third of cylinder a temp difference of 5 degrees C normally ensures good recycle times and hot water supply. Keeping boiler on eco setting and cylinder stat at 55 will satisfy most conditions. The amount of hot water produced relates directly to energy,Kw, used. but heat loss from stored water increases with temperature.

 

[Kotek Besar]

Okay thanks anyway. And thanks for all your advice and everybody else's advice this is a great website.