Weather compensation wtf?

[waxingsatirical]

Please tell me I am wrong with my understanding of weather compensation.

 

A compensation curve is setup which relates the outside temperature to the target flow temperature. Cold outside, high flow temp. Warm outside, low flow temp. 

 

So the internal temperature is not taken into account? If so, what happens when I light my 4kW wood burner? Does the heating system just merrily keep inputting as much heat as it assumes the house needs?

[SteamyTea]

2 minutes ago, waxingsatirical said:

Cold outside, high flow temp. Warm outside, low flow temp

I think it also takes the ΔT between the flow and return into account.

So it is really measuring two temperatures, and adjusting the flow rates/output temperatures to govern the power.

I may be wrong on that though.

[Dan F]

1 hour ago, waxingsatirical said:

Please tell me I am wrong with my understanding of weather compensation.

 

A compensation curve is setup which relates the outside temperature to the target flow temperature. Cold outside, high flow temp. Warm outside, low flow temp. 

 

So the internal temperature is not taken into account? If so, what happens when I light my 4kW wood burner? Does the heating system just merrily keep inputting as much heat as it assumes the house needs?

 

This the the case with basic weather compensation.  Most manufacturers have some kind of "room temperature modulation" option which wil adjust the curve based actual room temperature.  This approach helps adjust for solar gain and high wind as well.

Edited 9 hours ago by Dan F

[JohnMo]

Radiators or UFH?

 

UFH as it's close to room temperature, will stop outputting heat, so self compensates to a decent amount. Radiators maybe less so, or not at all. If you had a trv on the radiators in or close to the stove, they would modulate flow down in response to room temperature increase.

[Beau]

3 hours ago, SteamyTea said:

I think it also takes the ΔT between the flow and return into account.

So it is really measuring two temperatures, and adjusting the flow rates/output temperatures to govern the power.

I may be wrong on that though.

Thats how our old GSHP works

[G and J]

3 hours ago, SteamyTea said:

I think it also takes the ΔT between the flow and return into account.

So it is really measuring two temperatures, and adjusting the flow rates/output temperatures to govern the power.

I may be wrong on that though.

So if the woodburner or solar gain is heating the room the return temp will be high enough to stop the ASHP pumping?  
 

If so will the return from overheated rooms effectively redistribute heat a little to colder rooms?

 

[Dan F]

5 minutes ago, G and J said:

So if the woodburner or solar gain is heating the room the return temp will be high enough to stop the ASHP pumping?  
 

If so will the return from overheated rooms effectively redistribute heat a little to colder rooms?

 

Ours modifies flow temp based on room temp, not return temp!

[G and J]

1 minute ago, Dan F said:

Ours modifies flow temp based on room temp, not return temp!

Return temp is effectively, I presume, a weighted average of all rooms served by the UFH.  So if you have a fire in one room do the others then suffer a temperature drop?