40/69
Siemens Building Technologies
Electronic Air / Fuel Ratio Control System
CC1P7873.1en
HVAC Products
14 Error codes and rectification of faults
15.10.2002
Error code
displayed by
the unit
Text displayed
by the hand-
held terminal
Hints on the cause of the fault
Hints on troubleshooting
-14
disturb > 9.8
The signal at the correcting variable input
«X2» was > 9.8 V for more than 30 s.
The RVW26... interprets this as a fault and
the correcting variable is no longer consid-
ered for the fan speed (
®
excess air).
There will be no lockout.
Fault disappears as soon as «X2» reaches a
level of < 8 V.
Possible causes:
·
Air curve programmed with too much ex-
cess air
·
Setting of influencing factor «DISTURB»
(programming level 4) too low
·
O2 sensor or stack is leaking. Burner is
supplied with additional air (extraneous);
O2 trim control / RVW25… and RVW26…
do not sufficiently affect the O2 value.
-16
-17
stopswi aux1
stopswi aux2
The RVW26... measures and stores the po-
tentiometer position regarding the end switch
positions of the «AUX1 / AUX2» actuator.
The current value does not agree with the
stored values (deviation > 200 mV).
Check end switch positions.
Measure the end switches again (programming
level 2 of the RVW26...).
It must be observed that the end switch meas-
urement always refers to the selected type of
fuel.
Check whether the actuator can approach the
end switches with a reproducibility of <
±
200 mV
at the potentiometer.
Fault can also occur if the RZD20 has been re-
placed.
-19
-20
range pos aux1
range pos aux2
The feedback signal of the «AUX1 / AUX2»
actuator is outside the limits of 0.4...9.6 V.
Check wiring of the feedback potentiometer and
feedback potentiometer itself. Replace it, if
necessary.
-22
-23
act slow aux1
act slow aux2
The RVW26... monitors the change on the
feedback potentiometer when a positioning
step is made.
The change in position measured was
smaller than expected.
Check whether the set actuator running time
agrees with the real running time.
Check the potentiometer.
Geartrain of actuator may have too much
backlash or throttling unit does not easily travel.
-25
-26
act inver aux1
act inver aux2
The RVW26... monitors the changes on the
feedback potentiometer when a positioning
step is made.
The change in position measured was in-
verse to what it should have been.
Check if the potentiometer is correctly con-
nected (may be terminals «M» and «U10» are
mixed up).
Check if the actuator is correctly connected.
-28
-29
act fast aux1
act fast aux2
The RVW26... monitors the change on the
feedback potentiometer when a positioning
step is made.
The change in position measured was
greater than expected.
Check whether the set actuator running time
agrees with the real running time.
Check the potentiometer.
Check smooth and jerk-free movement of the
actuator drive shaft and potentiometer when the
end switches are measured (programming level
2).
-56
ratio fail
The RVW26... monitors the link between fan
and actuators.
The set position and the actual position of
one of the actuators were different for more
than 10 s.
Check if slope of the actuators is too steep.
Check digital communication.
Remove AZW... from the RVW25...
-57
load fail
The RVW26... monitors the lower load limit
(5 % «MinLoad» on the RVW25...) to detect
broken wires of load input «U1».
Check connections «X1» of the RVW25... to
«U1» of the RVW26... and «M» of the RVW25...
to «M» of the RVW26...
