Salus actuators

[dave1967]

Can these self balancing. salus actuators be adjusted so as to increase the flow/return difference to help combi efficiency.

[JohnMo]

No not really.  They are set for 4 degs delta T below 30 deg and 7 above.

[dave1967]

1 minute ago, JohnMo said:

No not really.  They are set for 4 degs delta T below 30 deg and 7 above.

Pity. Theyvwould be more efficient if they could be set for 15 deg

[JohnMo]

Can I ask why you are trying to set the delta at 15?

[dave1967]

1 hour ago, JohnMo said:

Can I ask why you are trying to set the delta at 15?

I'm not. Just reading up on codensing boilers and they work more efficiently with a great margin.

[dave1967]

Also do these not conflict with a stat if room temp overshoots 

[JohnMo]

6 minutes ago, dave1967 said:

I'm not. Just reading up on codensing boilers and they work more efficiently with a great margin.

That's not entirely true.  They condense once the return is at or below 54deg.  It is nothing to do with margin between supply and return.

 

The further the return temp is below 54 the more condensing that occurs, which increases efficiency.

 

Also on the UFH heating the output from the floor is based on the mean temperature (mid point temp between flow and return).  So a big difference between flow and return (assuming the same flow temperature) the lower the floor output.

 

[Fly100]

I built one of these, ( disregard the number on the top unit I only powered it to take a pic briefly) . So the Elliwell unit controls the boiler and I run it until the flow reaches 60c where it the cuts out. I can then set a differential figure which I set to 14c in the autumn and spring and 12 or 10c in the winter depending on the weather, at 46c it restarts the boiler for another heat cycle, reaching 60c it shuts down again. My oil boiler runs both under flow and rads and these figures are the sweet spot for both. The under floor flow is set to 40c and again I increase it slightly if the weather is very cold. These figures give me a return flow of around 42c ish. The unit below the Elliwell is a Flow and Return lcd read out and the unit below is an hour meter that clicks on when the boiler is running. Boiler runs for 500 hours per heating season, we have a large PV set up the provides DHW from March until about early October.

[dave1967]

10 hours ago, Fly100 said:

I built one of these, ( disregard the number on the top unit I only powered it to take a pic briefly) . So the Elliwell unit controls the boiler and I run it until the flow reaches 60c where it the cuts out. I can then set a differential figure which I set to 14c in the autumn and spring and 12 or 10c in the winter depending on the weather, at 46c it restarts the boiler for another heat cycle, reaching 60c it shuts down again. My oil boiler runs both under flow and rads and these figures are the sweet spot for both. The under floor flow is set to 40c and again I increase it slightly if the weather is very cold. These figures give me a return flow of around 42c ish. The unit below the Elliwell is a Flow and Return lcd read out and the unit below is an hour meter that clicks on when the boiler is running. Boiler runs for 500 hours per heating season, we have a large PV set up the provides DHW from March until about early October.

Thanks for the info flu.