Boiler not efficient

C

carol11

Hi , existing boiler was a potterton RS60 new boiler is an ecotec 618, heating temperature dial is set to 75 which is fine & radiators heat the house as good as the last boiler, however, i've been told to turn cental heating control down to 60 degrees which will save on gas usage, problem being the thermostat in the hall (existing) keeps the boiler on and the house never gets as hot as before.

Will i need to get larger radiators put in or just turn the boiler thermostat up? how does this work when temperature to radiators are lower with the newer type boilers?

TIA. x
 
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What is your roomstat set at, How many rads do you have, and the sizes of the rads.
set at 75 boiler wont be condensing
 
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The boiler is will not be the problem.

Don't always assume the room thermostat is showing the correct temperature. It is dependent on a number of factors.

Is it in the right room and place and set at the correct height.
Is it effected by drafts or near a radiator.

Check the room temperature against the room stat with separate thermostat, or set the room stat at what temperature is right for you and don't be too concerned with what is shown on the dial.
 

DP

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A radiator is sized to output heat lost from the room it is fitted in when outside temperature is -1 degree C. Let the room temperature be 20 degrees C. When outside temperature is -1, you will be loosing 21 degrees of heat. You will note, on the inside of the boiler flap, it says let the control be set to 75. At that setting heat going to the radiator will allow it to radiate heat that will maintain designated temperature in the room on account of water circulating at a higher temperature.

Middle of summer, outside is say at 14 degrees C (being generous there). Your radiator only needs to output heat that takes care of 7 degrees of heat loss. This is done by setting the boiler control to summer setting as per the label, therefore the circulating water is not as hot but radiator will still maintain design temperature of 20 degrees.

Fit a good quality programmable room stat and your troubles will be over.
 
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Hi , existing boiler was a potterton RS60 new boiler is an ecotec 618, heating temperature dial is set to 75 which is fine & radiators heat the house as good as the last boiler, however, i've been told to turn cental heating control down to 60 degrees which will save on gas usage, problem being the thermostat in the hall (existing) keeps the boiler on and the house never gets as hot as before.

Will i need to get larger radiators put in or just turn the boiler thermostat up? how does this work when temperature to radiators are lower with the newer type boilers?

TIA. x


It's the old turn down your boiler thermostat and save money advice that the government regularly puts out.

However, the government are not heating engineers.

If you have a modern system with all the latest controls fitted and your home is heavily insulated then you need to run your boiler thermostat on max - this allows all the individual controls to do their job as quickly and efficiently as possible and save you ££££s ((which is their purpose after all).
 
G

gasafengineer

Original boiler @ system were designed for a flow temp of 82k , return temp of 71k with an outdoor temperature of -1k , the new boiler has a max flow temp of 75k (adjustable to 85k) with a likely return temp of 65k , with this is mind radiator output load has decreased 35% , so in effect if original radiator heat loss was calculated to be 45k BTUs (13kw) @ a mean radiator temp of 55k , actual radiator heat load with new boiler running @ 75k flow temp would calculate to a loss of 12k BTUs (3.5kw) , maybe not an issue in mild weather but come winter either raise boiler temp to 75/85k or stick on that knitted cardigan. :mrgreen:

You can turn that room stat as high as you like , come that cold winter it won't make a blind bit of difference. ;)
 
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Got that, Carol? :mrgreen:

Who let the inmates out tonight? Five completely different answers already and some of them clearly didn't even read the question. :rolleyes:

So, here's answer #6! Turn the boiler stat down. 60C is a good starting point. If your heating works OK then smile. Remember the radiators won't get as hot (although close to 60C will still feel pretty hot) and the rooms will take a little longer to warm up. You could even try turning it down to 55C or 50C, depending on what selections your boiler offers, but I suspect that just won't be effective.

If 60C just doesn't cut it then turn it up a bit. Come winter you'll almost certainly have to turn it up a little.

Don't panic if you have to run at 75C. You'll be losing a couple of percent in efficiency but not worth replacing all the radiators just for that. Think about up-sizing if you are replacing radiators for some other reason.
 
M

mysteryman

Have weather compensation fitted, and it will do all that completely automatically.
 
M

monoxide62

Remember the radiators won't get as hot (although close to 60C will still feel pretty hot) and the rooms will take a little longer to warm up. .

Inmate # 6. :mrgreen:

No matter how long the heating is on the rooms will not warm up to design temp in cold weather if boiler temp is lower than design temp , like many others who believe simply increasing the temp on room stat will make the room hotter , WC has no bearing regards the OPs problem.
 
M

mysteryman

Weather comp has every bearing on this issue. It would control the flow temperature to the correct level at all times automatically, giving the right heat output with the best possible fuel economy.
 

DP

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OP wants to know if she needs bigger radiators. Almost certain she does not as old windows ( that contributed to large chunk of heat loss) will now almost certainly be PVC double glazed ones.

Chances are there are other factors that need to be looked at to come to final conclusion.
 
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The roomstat should be in the lounge, not in the hall. Correct that, and see what happens.
 

DP

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The roomstat should be in the lounge, not in the hall

Not always Ben. I have a gas fire in the lounge. It would be madness to fit a roomstat in the lounge.

I also have a second roomstat in the bedroom, so two zones on a combi
 
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Original boiler @ system were designed for a flow temp of 82k , return temp of 71k with an outdoor temperature of -1k ,

82 k, wow that sounds cold! I expect the air would be liquified.

Surely you cannot go below 0 k outside? I doubt that anything would still be moving!
 

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