IES-VE User Forum

Hi,

Can any advise me if an apache profile can be create that when the room temperature is reached then the heating goes off, but comes on if the temperature drop externally to a frost set point. i.e. weekends.

Mark

I think you are describing a standard setback style profile (setpoint during the day, 12C at night and weekends?).

If so you want to be using an absolute profile and apply it to the simulation heating setpoint rather than the heating profile. Create an absolute weekly profile which maps the varying temperatures you want at different times and then change the "constant" bit to "timed" and apply the profile in the box that comes up. Leave the heating profile as "on continuously".

for out of working hours would this formula work for two stage frost control if(to,to<5,0.5) | if(ta,ta<10,0.5), 0.5 representing 1/2 the temperature normally required and the same being applied for weekends

Modulating profile controls can only work in an on/off style for the temperature setpoints and so 0.5 multipliers will not work. Also, the first and second arguments of the functions appeaer the wrong way round.

As I said, you need to use the "absolute" profile control method or set up mic heating gains within the space and apply the modulating formula to those.

Ive tried the absolute method the only reason I'm trying the above is that i want the heating to come on either a) when the temperature in the building is below 10degc or b) externally below 5deg c. using the absolute method means that the temperature would always be on set back no matter what the external conditions are.

Ok, I think I understand.

You could use the absolute method but make the set back -50C which would mean it would never come on.

I think the absolute formulae would be (if your room setpoint is 20C):

if(ta<10,20,-50)|if(to<5,20,-50)

If that doesn't work it might be

if((ta<10|to<5),20,-50)