Periodic Valve Opening during Limitation Control

When the valve is closed during primary return temperature or primary supply temperature limitation control and the valve position VLV-01 = 0, it may happen that the standing water will remain at a high secondary supply temperature for a very long time and that the secondary consumers will not get their required heat.

To avoid this situation, this macro provides an option to open the valve periodically for the time VLV-04 in a fixed time interval of 10 minutes.

This function will be activated only if the valve is closed for the two limitation control functions:

The valve position during this time will be set to the position VLV-02. To disable this function set the parameter VLV-04 = 0.

Table 7.   Parameter List

Description

Value Range

Default Value

Unit

VLV-01: valve position limit

0...100

100

%

VLV-02: minimum valve position

0...100

40

%

VLV-04: valve open time at closed valve during limitation control

0...600

180

sec