Excessive LPG usage with Vaillant 828E

[newsliner]

I've had a Vaillant Ecomax 828E LPG combi boiler for just over a year now, in my 2 bedroom chalet bungalow. The house used to have oil-fired CH, but I changed it to LPG when the old boiler packed up.

On oil, it used to cost between 500 and 600 pounds a year to heat the house and the hot water. I was expecting LPG to be between 25 and 50% more expensive, but in the 2004 calendar year the LPG alone (without standing charges etc) cost nearly =A31300. I live on my own, and use barely any hot water, and only heat the house to 18 degrees (room thermostat) during the day and 16 degrees at night in the winter months (end of Oct - March) plus the odd blast if things get chilly.

Are there any obvious settings on the boiler I can check to make sure it's not just blasting gas out of the flue and warming the surrounding countryside? I don't think there are any leaks between the tank and the boiler.

Oh, and the house has been cavity insulated since it was on oil too.

John

[usenet]

I think that's probably just an indication of how much more expensive LPG is than oil for heating.

Next new boiler we get is going to be an oil one to replace an LPG one for just the above reason.

[Christian McArdle]

Even that is horrendous. Do you leave the windows open or something? If not, you've got a really serious lack of insulation problem here. Heating to only

18C and using little hot water, your bills should have been half that, or less. Get your insulation checked ASAP. Ensure your hot water cylinder has a thermostat that actually cuts the gas.

Christian.

[Pete C]

Is there much loft insulation, esp as you have a bungalow. Also is it a condensing combi?

cheers, Pete.

[newsliner]

It's not a condensing combi, and I don't have a hot water tank. I've had cavity wall insulation installed last summer, and had my loft insulation upgraded last winter when the new boiler was installed. It's not double glazed, but saying that, it wasn't double glazed when it was heated with oil either...

I'm a bit lost as to where to look next! Oil boilers???

[Pete C]

That might be jumping from the frying pan into the fire! Oil has gone up a lot over the last two years...

Worth checking that the loft insulation is at least a foot (IIRC the minimum for new builds) and all external doors and windows are properly draught proofed.

Also secondary double glazing (eg magnetic snap on glazing) would help if the windows are particularly large.

With the above it should also be possible to switch the heating off overnight without it getting too cold.

cheers, Pete.

[Ed Sirett]

I have no idea of the true relative cost of LPG against oil.

1) Check that the boiler is not running when it ought not to be. 2) if the green light is on all the while... ... Turn the HW control fully to 0 (there's a slight detent 0 and max) then up to the required setting this will extinguish the 'warm start' facility and the green light should go out. This will stop the boiler firing 30 seconds every 30 minutes. It's not a lot a but it will add up. It will take about 30s longer to draw hot hot water but if you do so infrequently the saving should be worth it. 3) A 28kW boiler must be so over rated for the a 2 bed bungalow. It might be worth turning down the max CH rate however some of the same can be achieved by turning down the CH temperature. The max CH rate is set up in software accessed through the front panel buttons - the instructions are in the book. but if you are not up to speed on 'programming' this type of gadget then leave it well alone as a lot of damage may be done by making the 'parameters' random. 4) Insulate and draught proof (but not so much you get condensation).

HTH

[Dave Liquorice]

Whilst this is true, it's now about 6p more per litre than it was. Oil is still roughly 10p/l cheaper than LPG and you get roughly the same amount of energy from a litre of oil as you do from a litre of LPG.

See a couple of recent threads in here.

[newsliner]

While I appreciate the significance of insulation etc, the point is that the house is the same as it was when it was on oil. If anything, it is now significantly better insulated, with the upgraded loft insulation and cavity wall. So to (at least) double the cost of the heating fuel seemed ridiculous. Unless there is something wrong with my boiler I'm going to convert back to oil - Calor are due to ring me...

Thanks for all the help and advice so far though - it's all appreciated.

[Dave Liquorice]

Seems wise, though the boiler itself might be fine, the control system might be not quite in as much control as it was though. That "warm start" feature mentioned earlier seems like a good way to waste fuel as well. 30s every hour doesn't sound much but that's 12mins/day or

18hrs/qtr...

[Martyn Pollard]

The 828E is a condensing combi according to the spec. Its sedbuk A, but seems it doesn't modulate down below 13.4kw for central heating. Ideally you should be aiming for 3 or 4 kw range otherwise. Also, weather compensation has to be a must for a LPG system. I would also move away from a combi when it comes to LPG, but other opinions may differ.

You could always sell it on ebay and install something like an ATAG or Viessmann boiler with the weather comp options. I doubt you'll get much change out of =A33k(installed) and it sounds like you're leaning towards oil anyway?

[Ed Sirett]

The OP did not specify whether it was a V. Ecomax 828E or a V. Turbomax+

828E the latter being a non-condensing model.

[Pete C]

Something else to consider is that oil has ~30% more energy per litre than LPG.

I don't know the current prices for oil and LPG but if LPG is 30% more expensive per litre, then it would cost 70% more per kWh overall.

cheers, Pete.