Using fuel in oil fuelled boiler - which setting uses less?

mwddrwg

Hi all,

We have an oil-fuelled boiler which powers our heating system and hot water.

I'v got a question about how the boiler heats the water and which is the most efficent way to use it. We used to have it coming on for around 30 minutes, twice a day, but the water was never hot enough. So now I've been advised to keep the boiler on so that it comes on just when the temparature goes below a certain level and then switches itself off.

Is this good advice or does this use more oil in the long run?

Any advice appreciated.

Thanks

HappyMJ

It'll use more oil in the long run but you will always have hot water. It's a trade off...spend more and know you always have hot water or save money and have only so much hot water.

You could set it for longer than 30 minutes to start with. Try 2 hours twice a day instead. That should give the boiler plenty of time to reheat a cylinder from cold. If you sill run out of hot water then set it to run 24 hours a day. It'll turn itself off once the cylinder reaches temperature.

Cardew

Provided you have a modern well insulated hot water tank(usually with a foam jacket) the losses from the tank are small.

IMO it is pointless having a CH system and then not have enough hot water for your needs.

alleycat`

Gas, not oil, but we have it set to come on twice a day for 40 minutes.
tank is set at 60C+.
The boiler is never on for that full length of time and we have enough water for a couple of baths (should we wish).

Seems odd the boiler can't get the tank up to temperature in that sort of time frame?

As Cardew has said the heat loss should be negligible from the tank assuming it is fairly modern / insulated.

mwddrwg

alleycat` wrote: »

Gas, not oil, but we have it set to come on twice a day for 40 minutes.
tank is set at 60C+.
The boiler is never on for that full length of time and we have enough water for a couple of baths (should we wish).

Seems odd the boiler can't get the tank up to temperature in that sort of time frame?

As Cardew has said the heat loss should be negligible from the tank assuming it is fairly modern / insulated.

Thanks for all your replies. The boiler was set for 30 minutes each time but not sure if it actually takes that long to get it up to temperature. Probably not, thinking about it. I think I'll monitor how often it comes on and for how long from now on and compare times.

mark-w20

Is hot water on a pumped or gravity circuit from the boiler, as that will be a major factor in any advice and also speed of hot water production. It will also have an effect on economy of the different methods you are suggesting running the boiler.

ash28

mwddrwg wrote: »

Hi all,

We have an oil-fuelled boiler which powers our heating system and hot water.

I'v got a question about how the boiler heats the water and which is the most efficent way to use it. We used to have it coming on for around 30 minutes, twice a day, but the water was never hot enough. So now I've been advised to keep the boiler on so that it comes on just when the temparature goes below a certain level and then switches itself off.

Is this good advice or does this use more oil in the long run?

Any advice appreciated.

Thanks

We have an oil fuelled boiler for heating and hot water....we have 3 bathrooms and 2 of them have showers that use water from the tank. The tank is massive (if you've been to the US and stayed in a villa think that sized tank).....we have the water on twice a day, once for an hour (morning) and once for 30 mins (evening). We don't have a header tank in the loft so the tank is fed direct from the mains supply.

We very rarely run out of hot water....it's usually hot and plenty of it. The only time we have had an issue was when we had visitors and there 5 showers in the morning....it emptied the tank of hot water.

But ordinarily we don't run out - there are 3 of us showering daily and the showers are powerful. The water isn't pumped.

I don't know leaving if the boiler on constantly will work out to be more expensive.....we actually do leave our boiler on constant in the winter through the day and evening (off over night) but only for the heating not the water.

ash28

alleycat` wrote: »

Gas, not oil, but we have it set to come on twice a day for 40 minutes.
tank is set at 60C+.
The boiler is never on for that full length of time and we have enough water for a couple of baths (should we wish).

Seems odd the boiler can't get the tank up to temperature in that sort of time frame?

As Cardew has said the heat loss should be negligible from the tank assuming it is fairly modern / insulated.

Our tank is huge, probably twice the size of normal water tank in an airing cupboard....it would take a while to heat it from cold. o Actually just had a look it and to reheat it takes 40 mins according to the manufacturer.

mwddrwg

mark-w20 wrote: »

Is hot water on a pumped or gravity circuit from the boiler, as that will be a major factor in any advice and also speed of hot water production. It will also have an effect on economy of the different methods you are suggesting running the boiler.

Our tank is in the airing cupboard on the first floor, boiler in the kitchen in the ground floor. When you open the hot water tap downstairs it takes around 30 seconds for the water to come up to full temperature (if the boiler has been on long enough to heat it ti the max) but comes through in less time in the bathroom upstairs. Probably a gravity circuit then?

alleycat`

It'll most likely be one of these:-

http://www.home-heating-systems-and-solutions.com/central-heating-design.html

I'd be surprised if the hot water is purely gravity but it isn't out of the question.

My hot water behaves how you describe but it isn't a gravity system.

It's actually a Y plan.

Look for the motorised valve(s) and you'll have the answer.

mark-w20

mwddrwg wrote: »

Our tank is in the airing cupboard on the first floor, boiler in the kitchen in the ground floor. When you open the hot water tap downstairs it takes around 30 seconds for the water to come up to full temperature (if the boiler has been on long enough to heat it ti the max) but comes through in less time in the bathroom upstairs. Probably a gravity circuit then?

Do not mean the hot water circuit as in the pipes to the taps, by gravity or pumped I mean the circuit from the boiler to the coil within the cylinder, a good start would be if you have 2 pipes at the boiler or 4, that keeps it simple, after that your looking for zone valves to confirm a pumped circuit.