Potterton Eurocondense Plus Installation Manual page 44

CONTROL STRATEGIES
Hot-water control
Automatic day heat limit
Rapid heatup
Rapid reduction (with room sensor)
Boiler frost protection
System frost protection
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The hot-water requirement has priority over heat requirement.
The automatic day heat limit is effective only when the outdoor temperature
sensor is connected.
This is a rapid-acting economy function, which switches off the boiler when
the mixed outdoor temperature is higher than the room temperature setting
(standard or reduced).
The boiler switches back on when the mixed outdoor temperature is 2 K
below the room temperature setting.
For outdoor temperature control with room influence, the actual room
temperature is taken into consideration.
The automatic day heating limit does not have a direct effect in "continuous
operation".
When the automatic day heating limit is active, "ECO" appears on the display
of the room control module RRG.
Only possible when room control module RRG is connected and room sensor
active. Quick heatup/quick reduction is effective only when the heating circuit
is switched over from frost protection or reduced mode to standard operation
and the room temperature is simultaneously more than 1.5 °C below the room
temperature setting (even when room temperature setting is increased on room
control module).
Quick heat up is terminated when the room temperature is less than 0.25 °C
below the room temperature setting.
When the heating circuit is switched over from Standard mode to Reduced
mode or Frost protection mode, the rapid reduction feature is active (heating
circuit pump is switched off).
If the boiler temperature drops below the temperature set for boiler frost
protection, the burner and heating circuit pump are started up. When the boiler
temperature increases to above the switch-off limit, the burner is switched off,
the heating circuit pump continues to run for the pump overrun delay time.
On systems with outdoor temperature sensor, the system frost protection
feature is switched on and off by the outdoor temperature. In this case, the
heating circuit pump is switched as follows:
Outdoor temperature Pumps
< 4 °C Continuous operation pumps ON
- 5 °C bis 1,5 °C Pumps on for 10 min. every 6 hours
> 1,5 °C Pumps OFF