Danfoss ECL Comfort 210 Installation Manual page 71

Installation Guide
Nz (neutral zone)
Circuit
1
Set the acceptable flow temperature deviation.
Set the neutral zone to a high value if you can accept a high
variation in flow temperature. When the actual flow temperature
is within the neutral zone, the controller does not activate the
motorized control valve.
If you want to tune the PI regulation precisely, you can use the following method:
• Set the 'Tn' (integration time constant) to its max. value (999 sec.).
• Decrease the value for the 'Xp' (proportional band) until the system starts hunting (i.e. gets unstable) with a constant amplitude (it
might be necessary to force the system by setting an extreme low value).
• Find the critical time period on the temperature recorder or use a stop watch.
This critical time period will be characteristic for the system, and you can evaluate the settings from this critical period.
'Tn' = 0.85 x critical time period
'Xp' = 2.2 x proportional band value in the critical time period
If the regulation seems to be too slow, you can decrease the proportional band value by 10%. Make sure there is a consumption
when you set the parameters.
Danfoss District Energy
ECL Comfort 210 / 310, application A231 / A331
11187
Setting range Factory setting
1 ... 9 K
Temp.
Critical time period
The neutral zone is symmetrical around the desired flow temperature
3 K
value, i.e. half the value is above and half the value is below this
temperature.
VI.LG.P1.02
Time
DEN-SMT/DK 71