Technical data

Installation and maintenance instructions ecoTEC exclusive 0020017768_0546
Code Meaning Cause
F.71 Constant value feed NTC Feed NTC faulty
F.72 Flow and/or return sensor fault Flow and/or return sensor is faulty (tolerance too great)
F.73
Signal water pressure sensor in the wrong range
(too low)
Line to water pressure sensor is interrupted or has
a short-circuit to 0V or water pressure sensor faulty
F.74
Signal water pressure sensor in the wrong range
(too high)
Line to water pressure sensor has a short-circuit at 5V / 24V
or internal fault in water pressure sensor
F.75
No sudden change in pressure was detected on
turning on the pump
Water pressure sensor or/and pump defective
Too little water in the appliance; check adjustable bypass;
Connect expansion vessel in return;
Air in the appliance
F.76 Interruption in cable harness Cable harness faulty
F.77
Condensate pump or return signal from accessory
module heating
Condensate pump faulty or return signal from the exhaust
gas flap has responded
con No communication with the printed circuit board
Communication fault between the display and the printed
circuit board in the switchgear box
Table 9.4 Error codes (continuation)
9.2 Test programs
Special functions can be triggered in the appliances by
activating various test programs.
These programs are given in detail in the Table 9.5.
• The test programmes P.0 to P.6 will be started when
"Power ON" is turned on and the "+" button is
pressed for 5 seconds simultaneously. The display
shows "P.0".
• Press the "+" key to start counting the test pro-
gramme number upwards.
• Press the "i" to operate the appliance now and to
start the test programme.
• Press "i" and "+" simultaneously to exit the test pro-
grams. You can also exit the test programs by not
pressing any button for 15 minutes.
Display Meaning
P.0
Bleeding test program The heating circuit and
the hot water circuit are bled via the automatic
bleeding valve (the cap of the automatic bleeding
valve must be released).
P.1
Test programme where the appliance is operated
in full load after successful ignition.
P.2
Test program where the appliance is operated with
minimum gas volume (ignition gas volume) after
successful ignition.
P.5
Test function for the safety temperature limiter (STL):
The burner is switched on with maximum output,
the temperature controller is switched off so that the
burner heats until the software STL responds by
reaching the STL temperature on the flow or return
sensor.
P.6
Filling/draining programme:
The preference changeover valve moves to the centre
position. The burners and pump are switched off.
Table 9.5 Test programmes
9.3 Resetting parameter to factory settings
Besides the option to reset individual parameters
manually to the factory settings specified in Tables 9.2
and 9.3, you can also reset all parameters
simultaneously.
• Change the value in the 2nd diagnosis level under
diagnosis point "d.96" to 1 (see Section 9.1.2).
The parameters of all adjustable diagnosis points now
correspond to the factory settings.
9 Troubleshooting