E93.1803.901 HW
84
During the ignition cycle multiple safety checks are active:
False flame detection
If flame is detected at the end of the pre-spark period (
Pre_Ignit
) a lockout error will occur.
Re-ignition
If at the end of the safety period no flame is detected the control will go to
Post_Purge
to
remove any unburned gas. After this a re-ignition attempt is started following the same cycle.
The number of re-ignition attempts is limited to
Max_Ignit_Trials
after which a lockout occurs.
Flame establishing
time
Sparking stops in the
Flame_Proving
state to allow for ionization detection. The
Flame_Prov-
ing
state takes
Safety_Period
-
Ignit_Period
.
Flame out too late
If at the end of the
Post_Purge
0 state the flame is still detected a lockout follows.
Flame loss
When a flame is lost during a burn cycle the control will restart the burner. The number of
restarts is limited by the
Max_Flame_Trials
setting.
Fan supervision
The fan speed is continuously monitored.
The following conditions for the fan speed are checked:
▪
The actual fan speed must be within 300RPM of the target fan speed
▪
When the fan speed duty cycle is within the lower/upper 5% of the PWM duty cycle
range no errors will be generated since the fan is in the limits of its working range.
13.1.14
C
ONTROL FUNCTIONS
Dependent on the required functions of the ap-
pliance and connected sensors and compo-
nents, several operation modes for Central
Heating (CH) and Domestic Hot Water (DHW)
can be selected, which are described hereaf-
ter.
The demand controls all work according to a
defined state machine. The diagram below
shows how the controller states are imple-
mented
Each state has a specific meaning for the con-
troller. Below the various states are explained
in more detail.
Controller
State
Description
Off
The controller is disabled. The controller cannot generate request from this state. When the controller is
enabled the controller state will move to the Idle state.
Idle
The controller is enabled. There is no request present. When a request becomes present the controller will
move to the Request state. In case the controller is disabled the controller will move to the Off state.
Request
The controller is enabled. There is an active request present. The active request is not yet accepted by the
demand controller. Once the active request is accepted the controller state moves to the Demand state.
When the request is lost the controller state moves back to the Idle state. In case the controller is disabled
the controller will move to the Off state.
Demand
The controller is enabled. There is an active request that has been accepted by the demand controller. The
control is actively handling its heat-request. This state does not mean that the burner is on. The burner state
can be monitored using the Burner State variable.
When the active request is lost the controller will move to the post-circulating state. When the priority for the
active request is lost the controller falls back to the Request state. In case the controller is disabled the con-
troller moves to the Post-circulating state.
Post-cir-
culating
The control is post-circulating. During this state the pumps continue to run for a short while. When the post-
circulation time has finished the control moves to the Idle state. When the post-circulation time has finished
and the control is no longer enabled the control moves to the Off state. When a higher priority demand
becomes active the post-circulation is ended and the controller moves to the Idle state.
Summary of Contents for CB 105 HW
Page 69: ...E93 1803 901 HW 70 12 6 Electrical schematic...
Page 70: ...E93 1803 901 HW 71...
Page 71: ...E93 1803 901 HW 72 12 7 Ladder Logic Diagram LOW MAINS VOLTAGE VOLTAGE...
Page 127: ...E93 1803 901 HW 128 22 SPARE PARTS CB 85 HW CB 105 HW and CB 125 HW exploded view...
Page 128: ...E93 1803 901 HW 129...
Page 129: ...E93 1803 901 HW 130 CB 155 HW exploded view...
Page 130: ...E93 1803 901 HW 131...
Page 145: ......
Page 146: ......
