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Siemens Building Technologies Electronic Air / Fuel Ratio Control System CC1P7873.1en
HVAC Products 18 Notes on the commissioning of a burner 15.10.2002
18 Notes on the commissioning of a
burner
· Check the actuators and adjust the end switches
Make certain the correct potentiometer is used (1000 W / 90° or 1000 W / 135°, de-
pending on the required mechanical angular rotation).
Check (rigid) connection between regulating unit and actuator.
Adjust the end switches and potentiometers:
Adjust the end switches «Fully closed» and «Fully open» such that the actuating
devices will be able to travel at least over the required mechanical angular rotation.
Adjust potentiometers and end switches so that there is a voltage of < 0.4 V in the
«Fully closed» position and a voltage of < 9.6 V in the «Fully open» position.
The voltage can also be measured directly with the AZW20.20.
If the end switch measurement is selected on programming level 2, the display will
show the current voltage.
100 %
78731e02/0601
A
U10 M
Y3
B1
Y4
Z
P
M
0 %
Fig. 28 Actuator with feedback potentiometer
Careful and correct adjustment of the end switches and potentiometers is
extremely important.
The steps indicated below are useless if this work has not been carried out
correctly.
· Connect the handheld unit AZW20.20 and switch the RVW26... to programming
mode
· Plants with O
2 trim control (or with application of a correcting variable at «X2»). For
the moment, switch the correcting variable off (that is, set «Disturb» on program-
ming level 4 to «0»)
· Select the required type of fuel (terminals «F1 / F2»)
· Make the settings on programming levels 1...6 according to the specific plant re-
quirements. For the moment, select 5 curvepoints (programming level 4, «SetPts =
5»)
· Measure the end switches. On programming level 2, trigger automatic measurement
of the end switches. Check if the measured values lie in the range of 0.4...9.6 V.
When using 2 types of fuel, the last 4 steps must be made for both types of fuel
· On programming level 5, set the 5 curvepoints for all actuators. This is the ba-
sic setting used to enable burner startup. The fine-tuning will be made later when
the burner is running, including measurement of the emissions
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