17kw boru chieftain - poor heat

19driver83

I installed a 17kW chieftain boru stove and the heat is very poor. Any tips?

The stove is in a 12ft x 12ft room heating 2x double rads, 4 singles and 2 smaller bathroom rads.

Getting reasonable hot water, rads get luke warm for short periods and the room is cold...barely know there was a stove in room.

Froststop

19driver83 wrote: »

I installed a 17kW chieftain boru stove and the heat is very poor. Any tips?

That stove is 15KW to the boiler and only 2KW to the room.

19driver83 wrote: »

The stove is in a 12ft x 12ft room heating 2x double rads, 4 singles and 2 smaller bathroom rads.

Just a rough calculation: 8 (rads) x 1.47KW = 11KW + 2.35KW (hw cylinder) = 13.93KW (14KW) Your nearly at the limit of the stove.

19driver83 wrote: »

Getting reasonable hot water, rads get luke warm for short periods and the room is cold...barely know there was a stove in room.

I think it's under pressure to keep up with the heating demand. The calculation about is only a guide, it dose not allow for KW's needed for pipe work etc, is there another boiler on the system? Is the stove heating that boiler also?

What is happening is when the temp rises the pipe stat is to the set point, it switches in the pump and moves all the hot water out of the boiler into the rads, this is replaced with cold water from the system. By time the boiler heats up again the water previously pumped out is after cooling.
What temp is the pipe stat set at?

19driver83

Correct the stove is 17kW (15 to water & 2 to room), although when I checked the nameplate attached it says 15kW rating.

What your saying makes sense and I think your right. Is it possible that the heat is also being pulled up the chimney? Even if u sat next to the stove with the door open the heat is poor.

The stat is set at 35.

The system is plumbed into the existing oil heating system.

I have sense turned off 1 of the single rads and the 2 double rads have stats on them which I turned down to 1. Marginal difference.

cranefly

I think the stat is too low at 35, that would mean the pump is on nearly all the time, water is constantly moving through your pipes at too low a temp, never getting a chance to really heat those rads or the room, try putting the stat at 55, this should give the water a good chance of staying hot until it gets to the rads, a 17kw stove should be able to heat all your rads to a decent temp, with only 2kw to room it is a bit low, but then the room is not really that big, we have the esse 350gs rated as a 14.7 kw stove 11 to the water and 3.7kw to the room, we have 13 rads working off it and it really does keep them hot, plenty of good smokeless coal keeps it going, its not one of those that keep going all night with a firelighter and one shovel of coal, you have to have a good fire down to keep all the rads hot.

Froststop

19driver83 wrote: »

Correct the stove is 17kW (15 to water & 2 to room), although when I checked the nameplate attached it says 15kW rating.

What your saying makes sense and I think your right. Is it possible that the heat is also being pulled up the chimney? Even if u sat next to the stove with the door open the heat is poor.

The stat is set at 35.

The system is plumbed into the existing oil heating system.

I have sense turned off 1 of the single rads and the 2 double rads have stats on them which I turned down to 1. Marginal difference.

Try turning down the pipe stat to 25, then 20. it will take longer to heat but may provide better results at the rads over time. You will need to figure out how to get it up to temp asap by driving the fire. If this provides a worse result then try turning the pipe stat up to 40 and see what happens. don't go over 65 as pipe stats are not that accurate. The last stove I fitted we had to set the pipe stat at 20 as it was out by 38 degrees. I fitted a buffer tank as the run from stove to rads and cylinder was approx 18 mtrs. The buffer tank was heated on gravity with the pipe stat fitted on the flow to the system and pump on the return from the system. This provided a mixing effect, giving the stove a chance to heat up to temp also. It resulted in a 16KW stove heating 750 ltr hot water and approx 11 rads to about 45 degrees. As the stove was running for long periods during the day it was sufficient to heat the hot water and rads. It all depends on the system. We found turning down the stat worked better.

cranefly

Surely if any pipe stat is out by 38 degrees the only logical thing to do is change the pipe stat, turning a stat down will not give better heat to the rads, at least i dont think it will, i will stand corrected if i am wrong.

If the nameplate attached to the stove says 15kw. then i cant see how boru can advertise this stove as 17kw it is misleading.

Froststop

cranefly wrote: »

Surely if any pipe stat is out by 38 degrees the only logical thing to do is change the pipe stat, turning a stat down will not give better heat to the rads, at least i dont think it will, i will stand corrected if i am wrong.

No pipe stat is accurate and all will be out by some few degrees. I usually check the temp of the pipe at the stat to make sure. Most are out by 10-20 degrees.
The OP states that he is getting reasonable hot water, he may also need to balance the cylinder coil if there is a balancing valve fitted, as this could be adding to the problem.
Regarding the stat temp, in his situation the rads are cooling faster than the stove can heat. If the stat is turned down the pump runs more often, it's a matter of finding the correct temp to get the heated water to return to the stove asap. If the pump runs constantly it may even provide a better result. The heated water has less chance cooling as its moving constantly, thus returning to the stove at a higher temp & gives the stove a better chance of heating. However the OP may need a buffer tank fitted.

cranefly wrote: »

If the nameplate attached to the stove says 15kw. then i cant see how boru can advertise this stove as 17kw it is misleading.

The nameplate is probably referring to the water boiler only.