andrews R18 Series, Technical Documentation Manual

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18IP22B
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2.3 Principle of regulation The flow temperature can be adjusted continously as a function
2.3.1 EM Control option Electronic Modulating version
of hot water demand and water hardness (see table 2 and 3).
Several boilers can be connected by using cascade switching.
With the EM or EW Control option you can reduce electricity
consumption, both boiler and boiler primary pump can be
switched off by the cascade control box.
This type of boiler control regulation (indicated by the EM
control option) uses a built-in PID regulator to maintain a con-
stant flow temperature to within a minimum temperature devia-
tion of +1 to -1 K. This system allows the user to fine-tune the
reaction of the boiler to the heating system or application pro-
cess. An added bonus with this “EM” control system is that it
allows a Building Management system to influence the flow
temperature using a 0 - 10 VDC control signal.
Boiler temperature controller RWF40
A Process value (actual temperature)
B Set point (temperature)
C Burner enable (not applicable)
D Mod. indicator (decrease fire rate)
E Mod. indicator (increase fire rate)
F Two-stage firing (not applicable)
G Limit comparator
H Manual operation
The keys K-L-M-N are used for displaying
values and changing parameters in the
temperature controllers configuration.
K Down key (reduce value)
L Up key (increase value)
M Programme key
N Exit key
Assignment of levels
All levels can be accessed from the basic
display via the
button, as shown in PGM
the diagram. The upper actual value dis-
play (red) indicates the actual value and
the parameter values for the various levels.
The setpoint and the parameters are
indicated in the lower setpoint display
(green).
1. After using
*
PGM
+
to step through all
the parameters of a level, an automatic
return occurs after the last parameter has
been confirmed.