Iii.a.9) Return Protection; Iii.a.10) Room Thermostat Reduction - Tech Controllers EL480zPID User Manual

User manual
The more points there are available for constructing the curve, the greater is its accuracy, which
allows you to determine its shape in a flexible way. In our case, four points seem to be a very
good compromise between accuracy and ease of setting its shape.
Where in our controller:
X = -20ºC,
A
X = -10ºC,
B
Y , Y , Y , Y – set-point valve temperatures for their corresponding outside temperatures: X
A B C D
X , X , X
B C D
After weather control is enabled the valve set-point parameter is calculated based on the
heating curve. By changing this parameter you can decrease or increase all the weather control
settings.

III.a.9) Return protection

This feature allows you to enable protection for the boiler from excessively cold water returning
from the main circuit, which could cause the boiler to suffer from low-temperature corrosion.
The return protection function works to ensure that when the temperature is too low the valve
will close partially until the short circuit of the boiler reaches the desired temperature. This
feature also protects the boiler from a dangerously high return temperature to prevent water
from boiling.
When this function is enabled you need to set the minimum and maximum return temperatures.

III.a.10) Room thermostat reduction

This function is active only when the unit is operated with a (standard or TECH) room
thermostat. When the room thermostat reaches the desired temperature in the house/flat
(reports heated up condition), the valve will close to such an extent so that the temperature
downstream of the valve drops by the <room thermostat reduction> temperature.
X = 0ºC,
C
X = 10ºC,
D
14
,
A