Wood pellet boiler performance

Energysaver

What sort of consumption are people getting from wood pellet boilers?
I have a 200m2 det. house with underfloor heating throughout and solar panels. Boiler also provides hot water for showers. The house is new and is well insulated.

I had a 3 tonne fill in July and I reckon I've used 2.5 tonnes since then. On that basis I will probably use over 5 tonnes of pellets in a year (which is higher than I expected). How does that compare to other peoples experiences?

MicktheMan

Energysaver wrote: »

What sort of consumption are people getting from wood pellet boilers?
I have a 200m2 det. house with underfloor heating throughout and solar panels. Boiler also provides hot water for showers. The house is new and is well insulated.

I had a 3 tonne fill in July and I reckon I've used 2.5 tonnes since then. On that basis I will probably use over 5 tonnes of pellets in a year (which is higher than I expected). How does that compare to other peoples experiences?

Energysaver, your house is new and so is still drying out. This results in higher energy use in year one. This may explain the higher than expected use of pellets.
Also what does "well insulated" mean? IMO a lot of houses are well insulated on paper but are badly insulated in reality due to shoddy workmanship.

Energysaver

MicktheMan wrote: »

Energysaver, your house is new and so is still drying out. This results in higher energy use in year one. This may explain the higher than expected use of pellets.
Also what does "well insulated" mean? IMO a lot of houses are well insulated on paper but are badly insulated in reality due to shoddy workmanship.

The heating has been on since about November of last year so I didn't take the consumption for the first 9 months into account for the drying out reason that you mention. It is a wood frame with 200mm of rockwool in the walls and 300mm in the attic. There is 200mm insulation in the floor. I kept a close watch when the insulation was installed so I think the workmanship was pretty good. I reckon the insulation is about up to the requirements of TGD Part L 2007 (in theory ).

No6

I have an old farmhouse which was refurbished in 2001/02 with some extensions and I used two loads last year. I've got standard Rads and no solar and the house is only about 150m² but it only costs 1200 a year to heat which is a lot better than I was doing with oil. I'm possibly not using the heating as much everyday mainly because my wife dosn't know how to make it work!!:D Unlike the oil which she had on for hours and hours every day!!:D

wazzoraybelle

Sorry off topic, but what price are woodpellets at the mo. Ta.

Energysaver

No6 wrote: »

I have an old farmhouse which was refurbished in 2001/02 with some extensions and I used two loads last year. I've got standard Rads and no solar and the house is only about 150m² but it only costs 1200 a year to heat which is a lot better than I was doing with oil. I'm possibly not using the heating as much everyday mainly because my wife dosn't know how to make it work!!:D Unlike the oil which she had on for hours and hours every day!!:D

I'll pretty much have used 2 loads in 12 months also but I've got solar and presumably your house isn't as well insulated so my system isn't looking very efficient.

Energysaver

wazzoraybelle wrote: »

Sorry off topic, but what price are woodpellets at the mo. Ta.

About €625 for 3 tonnes bulk delivery. I don't know if they charge more if you live further from the plant.

Energysaver

No6 wrote: »

I have an old farmhouse which was refurbished in 2001/02 with some extensions and I used two loads last year. I've got standard Rads and no solar and the house is only about 150m² but it only costs 1200 a year to heat which is a lot better than I was doing with oil. I'm possibly not using the heating as much everyday mainly because my wife dosn't know how to make it work!!:D Unlike the oil which she had on for hours and hours every day!!:D

No6, What make of boiler are you using?

No6

Gerkros woodpecker 30kw

richardn

I have an Opop Pellet Boiler.

2300 sq ft house timber frame

UFH downstairs, rads upstairs. Family of 5.

Last year I used 3.5-4 tonnes.

I have the UFH on generally October to March for about 4-6 hours a day from about 9am to 2pm

My plumber often asks if I have the UFH on all the time, which I reply no. He reckons I would save more pellets if I had it on 24/7 - what are people's thought's on this? There does not seem to be a definitive answer from anyone (having read the forums some do and some do like I do)

The UFH in my house runs at about 40 degrees in the 6 hour duration it's on but not every zone will reach that temperature unless I hit the boost panel for an extra hour or two (I only do this when house isn't warm enough) So I assume the whole of the slab is not heating up in that time period hence my question should I leave it on 24/7?

Chimpster

richardn wrote: »

I have an Opop Pellet Boiler.

2300 sq ft house timber frame

UFH downstairs, rads upstairs. Family of 5.

Last year I used 3.5-4 tonnes.

I have the UFH on generally October to March for about 4-6 hours a day from about 9am to 2pm

My plumber often asks if I have the UFH on all the time, which I reply no. He reckons I would save more pellets if I had it on 24/7 - what are people's thought's on this? There does not seem to be a definitive answer from anyone (having read the forums some do and some do like I do)

The UFH in my house runs at about 40 degrees in the 6 hour duration it's on but not every zone will reach that temperature unless I hit the boost panel for an extra hour or two (I only do this when house isn't warm enough) So I assume the whole of the slab is not heating up in that time period hence my question should I leave it on 24/7?

In reply to you I would say that I have a house of similar size,heated with UFH and an OPOP boiler. I leave it on all the time at approx 35 deg and my usage for last year would be just under 3 tonne. The circuit was completly off from May to Sept.

One thing, I have a 16Kw OPOP boiler but my boiler is currently running at 9kw, there is a facility in the chip to change it. When my boiler runs at 100% the flame is still remains quite small. So basically I have fine tuned it to the last.

The house is well insulated and has an air tightness of under 5m3/hr/m2 so heat loss from it minimal. I also have alot of solar gain from big windows on the south and west so these zones would rarely call for heat during sunny days.

richardn

Hi Chimpster, a quick question for you.

My boiler cuts out after 2 hours if the temp is not reached on the boiler.

Now I have my boiler set at 70 degrees for the rads and hot water but the UFH is set on a separate control to 40 degrees, however, 'cos the boiler doesn't ever reach 70 when the UFH is on the boiler cuts out with "L0" error so at the moment I have it set to come on for 1 hour and 50 minute periods.

Do you know if I can set the boiler to ignore the 2 hour "L0" situation?

Chimpster

richardn wrote: »

Hi Chimpster, a quick question for you.

My boiler cuts out after 2 hours if the temp is not reached on the boiler.

Now I have my boiler set at 70 degrees for the rads and hot water but the UFH is set on a separate control to 40 degrees, however, 'cos the boiler doesn't ever reach 70 when the UFH is on the boiler cuts out with "L0" error so at the moment I have it set to come on for 1 hour and 50 minute periods.

Do you know if I can set the boiler to ignore the 2 hour "L0" situation?

You appear to be using a slightly different control panel than the one I have. I am using a bio comfort panel, you may have a scotty?

Anyway, based on the issue you have presented it looks as though your boiler is struggling to make the 70 degrees. There could be a few reasons for this.

1. The boiler is undersized.
2 You are not feeding it enough pellets
3. the pump is not driving the water around the circuit quick enough.
4. The stat is not reading the temp of the flow pipe correctly.

70 degrees is quite high, your analoge temp guage at the front of boiler will give the temp usually a bit higher. So I would suggest that you could reduce the temp on the control panel down to 65. Make sure that your stat from your panel to your boiler is firmly connected to the flow pipe from the back of the boiler. Cover it up with a small length of armaflex insulation.

See how this goes.

richardn

Thanks Chimpster.

I am using a Scotte control panel.

I did wonder about the pump, I'm sure we set it to the minimum on installation so I'll turn that up.

The boiler does reach the 70 on the rads and the hot water with no problem but it will never reach 70 on the ufh as I have a 3 way valve in which restricts it to 45 (max 65) hence the boiler cuts out after 2 hours. There is a way of setting it which the installer is coming back to me on.

Thanks for your advice.

Chimpster

richardn wrote: »

Thanks Chimpster.

I am using a Scotte control panel.

I did wonder about the pump, I'm sure we set it to the minimum on installation so I'll turn that up.

The boiler does reach the 70 on the rads and the hot water with no problem but it will never reach 70 on the ufh as I have a 3 way valve in which restricts it to 45 (max 65) hence the boiler cuts out after 2 hours. There is a way of setting it which the installer is coming back to me on.

Thanks for your advice.

Yeah Unfortunatly you have the ineffecient situation of heating water to 70 degrees and then having to cool it to 45 degrees for UFH. To be honest UFH should work ok at 35 degrees so this could be reduced further. Your UFH should also be controled by a room stat which should override the pump/motorized valve for the UFH zone. Once the room hits 21 degrees then the UFH zone should switch off.

richardn

Pump is set to max Chimpster.

To be honest we had a bollox of a plumber who we parted company with some time ago!

If I set the boiler to 40 and left it on 24/7 for water and ufh I wouldn't get the cut off problem, I could then set my emersion to boost the water up to 70 on a timer, that gets round the water situation but still leaves rads working at only 40 degrees. If the UFH is on 24/7 I wonder will the house be warm enough to have the rads working so low?

I did have the room stats but in our plumbers infinite wisdom he decided against fitting them as he reckoned the boiler would be forever turning on and off which was BS as only the individual zones turn off (as you correctly state) and the boiler remains on.

If I knew what I know now the room stats would have gone in! They still can go in but it just means additional work and paying out yet again. I doubt this would fix the hot water and rad situation though?

Any suggestions?

Would a different control panel solve the problem?

corkonian0110

Useful thread folks, glad I found it.
Moved into a 2700sqft house in August, timber frame, well insulated and Kedco X (which is an opop ) 30kw. We have underfloor up and downstairs. Was also wondering about leaving the boiler on full time as once it hits 60degrees it modulates down from 100% to tip away at 20% or so. But for the moment i have it coming on in the morning at 5.30 off at 8.00, back on at 4.30 till 8. I have been playing around with the times as it doesnt even achieve full temp in the early morning run. gone through about 1.5tonne, the solar contribution is negligible at present for the hot water.

richardn

Well I managed to set the Scotte control panel to do as I wish, for anyone with same it is on the secret menu, hold set down for 6 seconds and L1 flashes up, use the arrow keys to move to b1 and set to 245.

Chimpster is correct though, what is now happening boiler races up to 70 or whatever setting you have, 60 seems standard but my Wife likes really hot water! The ufh only requires 40 or 45 degrees so the valve stops anything over 45 coming in but the boiler remains at 70. Inefficient? Possibly, although watching what the boiler does it doesn't throw in many pellets as it's such a small amount of water it's keeping at 70.

One other thing I can do now is have the rads and hot water and ufh on at the same time, I could never do that prior to setting it the way I have now.

I'll know in about 6 months how many pellets I have used but I think if I put the rads and hot water on at same time as ufh that should make use of the boiler keeping itself to 70.

Mothman

Also bear in mind the cold of this Autumn and Winter compared to recent years. I'd imagine that space heating requirements could be as much as double.

Coolest Autumn for 8 to 15 years and coolest first half of Dec since about 1995.