Oil burn efficiency

thebagman

Hey all,

I have a two storey house, new build, hence first winter in it. Oil fired ch.

I have ufh downstairs and rads upstairs both are seperate zones on timer controls. Its is a 35kw riello burner with Heatmiser control unit for ufh.

I would like some advice on boiler efficiency in the following situations if possible...

1. Does the boiler burn more kerosene if both zones are on together or does it burn at the same rate as if only one zone is on?

At the moment theboiler is operating a 90 seconds on/off cycle with only ufh on

2. Would it burn for a longer cycle if both zones are on?

3. Is it more effecient to keep a mean ufh temp of 21 or 18 deg, Will a floor cool quicker if colder hence causing a longer re-heat time?

All replies much appreciated...

Bagman

dpofloinn

1 it burns more because the load is larger
2 yes because the load is larger
3 i would aim for 21 deg personally

Will a floor cool quicker if colder hence causing a longer re-heat time?
That depends on the materials used to create the floors,the number of external walls,windows,doors,the size of the area being heated

TPM

thebagman wrote: »

Hey all,

I have a two storey house, new build, hence first winter in it. Oil fired ch.

I have ufh downstairs and rads upstairs both are seperate zones on timer controls. Its is a 35kw riello burner with Heatmiser control unit for ufh.

I would like some advice on boiler efficiency in the following situations if possible...

1. Does the boiler burn more kerosene if both zones are on together or does it burn at the same rate as if only one zone is on?

At the moment theboiler is operating a 90 seconds on/off cycle with only ufh on

2. Would it burn for a longer cycle if both zones are on?

3. Is it more effecient to keep a mean ufh temp of 21 or 18 deg, Will a floor cool quicker if colder hence causing a longer re-heat time?

All replies much appreciated...

Bagman

what sort of controls are on the underfloor heating? individual room control, single stat, time clock etc.
One option with underfloor heating and oil boilers is to run the heating with all loops/zones for a few periods throughout the day to build up and maintain the desired temperature in the rooms. this method concentrates the heating demand to these periods instead of heating individual rooms at different times, it should help reduce the short cycling

35kw boiler is going to be a problem with underfloor heating without a buffer tank.
The boiler is going to be running around 60c the underfloor should be running much lower than this, combined with flow rates, return temperatures the boiler will short cycle(cut in and only run for short periods) when only the underfloor heating is on, as you are experiencing. this is both bat for the boiler and the oil consumption.

What size is your house? it may be possible to jet down the boiler to a lower heat output which would also be an advantage

sullzz

Would your car use more fuel pulling a trailer loaded with weight , of course it would , same goes for your boiler , if it has more work to do its going to burn more fuel .