Operating Modes; Low-Fire Operation - Siemens RWF50.3 User Manual

Thermostat function
Heating controller
Cooling controller
Building Technologies Division
Infrastructure & Cities Sector
5

Operating modes

5.1 Low-fire operation

Low-fire operation means that only small amounts of heat are drawn from the boiler.
Using relay K1 Burner release, the 2-position controller ensures control to the setpoint
by switching the burner on and off like a thermostat.
This mode of control is known as the thermostat function. An adjustable switching
differential ensures that the burner's switching frequency can be selected, aimed at
reducing wear.
ON
OFF
Figure 6: Control sequence of heating controller
If the controller is set to cooling mode, temperature limits HYS4 and HYS6 apply. In that
case, relay K1 Burner release is used for controlling the cooling equipment.
ON
OFF
Figure 7: Control sequence of cooling controller
User Manual RWF50...
5 Operating modes
Modulating and 2-stage operation:
Actual value lies between switch-on
threshold HYS1 and switch-off threshold
HYS3.
7866d03e/1011
Modulating and 2-stage operation:
Actual value lies between switch-on
threshold HYS4 and switch-off threshold
HYS6.
7866d04e/1011
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CC1U7866en
25.07.2014