Bosch Installation Manual

Heatronic boiler control settings
61
Greenstar – 6721822579 (2021/01)
Service function 8.b: Code plug number
The last four digits of the code plug number are shown.
The code plug determines the appliance functions. If the appliance has
been converted from natural gas to LPG (or vice versa), the code plug
must be replaced.
Service function 8.C: GFA Gas burner control unit status
Internal parameter. If you are on the line with Bosch Technical Support
you may be asked for this number.
Service function 8.d: GFA Gas burner control unit fault
Internal parameter.
Service function 8.E: Restore boiler to factory settings
This function allows resetting all parameters of the boiler including all
service functions to their factory settings.
▶ Press and hold the service button until it lights up.
The display shows a code such as 1.A (first service level).
▶ Press and hold button and key pad lock button simultaneously until a
service function, e.g. 8.A, is displayed (second service level).
▶ Repeatedly press the key pad lock button or button until service
function 8.E is displayed.
▶ Press and release the emissions test button .
The emissions test button lights up and the display shows 00.
▶ Press and hold the emissions test button until the display
shows appears on the display.
All settings are reset and the appliance restarts with the default
settings.
▶ Reset altered service functions to the settings recorded in the
commissioning log ( page 78).
Service function 8.F: Permanent ignition
NOTICE
Ignition transformer damage.
▶ Never leave this function on for longer than 2 minutes at a time.
This function enables permanent ignition without gas supply to test the
performance of all ignition related components.
The following settings are available:
• 00: Off
• 01: On
Default setting is 00.
Service function 9.A: Constant mode
This function permanently sets one operating mode ( "Service function
2.F: Operating mode", page 58).
The following settings are available:
• 00: Default mode: the appliance runs according to control settings.
• 01: The appliance runs permanently at minimum output. The display
shows 9.A.
• 02: The appliance runs permanently at maximum output. The display
shows 9.A.
Default setting is 00.
Service function 9.b: Current fan speed
This service function allows you to display the current fan speed in
revolutions per second (1/s).
Service function 9.C: Current boiler output
This service function displays the current boiler output (in percent (%)).
Service function 9.d: Set fan start speed
At higher elevations the boiler fan may need to spin faster upon startup
to ensure reliable ignition every time. The start speed of the boiler fan
can be set from 45 to 77 revolutions per second (1/s).
Default setting is 50.
Service function 9.E: Turbine signal delay (only combi boiler ZWB...-
3A)
NOTICE
System damage or boiler malfunction!
▶ Never change the setting of this service function on heating boiler
ZBR...-3A appliances.
This service function allows setting a time delay to prevent the appliance
starting up as a result of transient pressure spikes in the water supply.
Through spontaneous pressure change in the water supply, the flow
meter (turbine) can signal that DHW is being drawn and cause the burner
to come on unnecessarily.
The turbine signal delay can be set from 02 to 08 (0.5 seconds to
2 seconds) in increments of 0.25 seconds.
Default setting is 04 (1 second).
Service function 9.F: Heating zone pump post purge
This service function allows setting a pump post purge time after the end
of the heat demand from the external control.
The pump post purge time can be set from 01 to 10 (1 to 10 minutes).
Default setting is 03.
Service function A.b: Display DHW temperature
This service function allows displaying the current DHW temperature.
Service function A.C: Display DHW tank temperature
This service function allows displaying the temperature of the DHW tank
temperature sensor.
Service function b.F: Solar DHW backup heating delay (only combi
boiler ZWB...-3A)
For systems with a solar thermal DHW tank in series before the DHW line
of the combi boiler. DHW heating by the boiler will be suppressed
expecting that solar thermal DHW will reach the hot water temperature
sensor prior eliminating the need to run the boiler. Set the heating delay
in accordance with system conditions.
If this setting is enabled, the DHW demand signal is no longer available
 page 52.
The start delay can be set between 00 to 50 (0 to 50 seconds) in
increments of 1 second.
Default setting is 00.
Service function C.d: Display current heat demand
Available displays are:
• 00: No heat demand
• 01: Space heating demand present
• 02: DHW heat demand present