Combi Boiler Stat Temperature

nuke1

Hi,

My home is about 6 months old, so everything is new, has a combi boiler and radiators with individual temp settings on them.

The main thermostat is in the lounge (set on timer to come on when im in), right next to my pc so I have to set it higher than usual due to the heat from the computer effecting the stat, but this isn't really an issue.

On the boiler it has 2 temperature settings, one for water and one for the heating, the water one I have set on max (65) which I won't lower since with it on max the shower isn't hot on max temp.

The temp stat goes up to 80 something, Would It be cheaper to set this to max or to set it to 65, same as the water? I have noticed at 65 the radiators are on constantly when I'm in right now since it is very cold outside, if set to max they are on less but still the majority of the time.

Either way the heating is comfortable, but I do have to set the room stat a few degrees higher if the boiler stat is on 65.

Trying to work out the cheapest way to run things, thanks!:)

DVardysShadow

It looks like your water temp is in deg Celsius whereas your room temp is in deg Fahrenheit. So the question of setting the same temps does not really arise.

nuke1

DVardysShadow wrote: »

It looks like your water temp is in deg Celsius whereas your room temp is in deg Fahrenheit. So the question of setting the same temps does not really arise.

I probably didn't explain myself too well, all temps are in celsius.

I have 2 on the boiler, 1 in the lounge.

The 2 on the boiler are one for water and one for the heating, both currently set to 65 but heating one can go up to 80something.

The one in the room is set to 25 right now

edited original post to fix my error

karl-123

any boiler is cheaper on full temperature,

motorway miles......... compared to city miles,

" boiler cycling " firing on, firing off, firing on, firing off,
wastes fuel,

as does wrong " siting of roomstats " there are rules on roomstats positions,
i have appeared in court many times for consumers taking " big "
companies to court,your post reminds me of one in particular,

it was a £ 3,500 back boiler change 20 years ago,the roomstat was above a radiator in the bedroom next to the cylinder cupboard,with live exposed wiring to it,and on hot water only, the upstairs radiators got hot, they did not before,the gravity/pumped common return to the back boiler was not installed .......corectly....restrictor tee/venturi tube ect,
after court the customer was fully refunded,he got a free back boiler,
1 person in a thousand complains .........se la vie .......:A

macman

I would suggest you try it on about two thirds of the maximum for the CH setting.
But why not either move your PC, or move the room 'stat? If it's a wireless one then the latter should be a 10 minute job for you.

nuke1

macman wrote: »

I would suggest you try it on about two thirds of the maximum for the CH setting.
But why not either move your PC, or move the room 'stat? If it's a wireless one then the latter should be a 10 minute job for you.

I don't honestly mind having it there, it just works out that i have to put the stat on 25 instead of 20, its not wireless sadly.

two thirds would be about 56 so i guess 65 is alright then?

macman

Turn the knob two thirds around. Use that as a basis to experiment.

iamcornholio

Condensing boilers work more efficiently when the return temperature (water in the CH circuit) is cool

You probably need to check the boiler manufacturers recommendations

For the water temperature, then that is really a summer/winter thing and you turn it up in winter when the incoming mains water is much colder

ziggyman99

Karl, as usual, is off on own tangent. Ignore him. He's talking about boilers from the last century, not modern technology. He talks nonsense most of the time and should be completely ignored.
Kar - How can the installer be responsible if the customer decides to place a computer below the stat? You'll be telling me next that the stat should be in the hallway.
Your boiler is a condensing boiler and as such should be run at a lower water temp in an attempt to keep if in condensing mode. Ideally 55C on the return. Unfortunately your system was probably sized for a delta T of 50C, i.e. a radiator temp of 70C(delta T= rad temp-room temp.) It happens. Installers use old Mears calculators to size the radiators. In addition, it seems that your radiators may have been undersized in the first place if they are running all the time even with the mild weather we are having, so running at a flow temp that would be ideal for condensing is unlikely. It may be that the heat loss wasn't even calculated properly but the radiators "sized" on what the builders had available! That happens aswell.....
As for the postion of your room stat.... it could be better sited. Can you move the computer? Is the stat a wireless version? If so, can it be moved?

nuke1

ziggyman99 wrote: »

Karl, as usual, is off on own tangent. Ignore him. He's talking about boilers from the last century, not modern technology. He talks nonsense most of the time and should be completely ignored.
Kar - How can the installer be responsible if the customer decides to place a computer below the stat? You'll be telling me next that the stat should be in the hallway.
Your boiler is a condensing boiler and as such should be run at a lower water temp in an attempt to keep if in condensing mode. Ideally 55C on the return. Unfortunately your system was probably sized for a delta T of 50C, i.e. a radiator temp of 70C(delta T= rad temp-room temp.) It happens. Installers use old Mears calculators to size the radiators. In addition, it seems that your radiators may have been undersized in the first place if they are running all the time even with the mild weather we are having, so running at a flow temp that would be ideal for condensing is unlikely. It may be that the heat loss wasn't even calculated properly but the radiators "sized" on what the builders had available! That happens aswell.....
As for the postion of your room stat.... it could be better sited. Can you move the computer? Is the stat a wireless version? If so, can it be moved?

stat isn't wireless so i am reluctant to move it, the computer I have connected to my TV which is in the only place to really put it otherwise I would move it.

There is one thing however, I have 3 radiators turned off.

1) in a bedroom which is never used (door always shut)
2) since my computer releases a lot of heat, I turned off one of the radiators in the lounge (the only one still running is a small one which cannot be shut off)
This is because before this room would be warm and the bedroom and bathroom would be cold as the 2 radiators + computer were heating up this room much faster than the others.
3) there is one by the front door which is next to some stairs that go straight into the lounge (no door between stairs and lounge) I turned that one off as its just heating up the entrance

Maybe turning the 2nd one on might be worth a try again?

ziggyman99

iamcornholio wrote: »

Condensing boilers work more efficiently when the return temperature (water in the CH circuit) is high - ie still hot.

You probably need to check the boiler manufacturers recommendations

For the water temperature, then that is really a summer/winter thing and you turn it up in winter when the incoming mains water is much colder

Wrong. Water doesn't CONDENSE if much above approx 55C. The cooler the return temp, the better. Condensing boilers work best with underfloor heating were the flow and return temps are lower.