Test Programs; Resetting Parameters To Factory Settings - Vaillant ecoTEC VU 656/4 Installation And Maintenance Instructions Manual

9 Troubleshooting
Code Meaning
F.72 Flow and/or return temperature sensor fault
F.73 Error in water pressure sensor
F.74 Water pressure sensor signal outside correct range
(too high)
F.75 Error, pump water shortage
F.77 Error, flue gas flap/condensate pump
con No communication with the printed circuit board
Table 9.4 Fault codes (continued)
9.2

Test programs

Special functions can be triggered in the boilers by
activating various test programs.
The test programs P.0 to P.6 are started as follows:
• Push the "+" button and hold it down.
• Push the "Fault clearance key" once or switch the
main switch off and on again.
After approximately 5 seconds, P.0 appears in the dis-
play. You can now release the "+" button.
• Push the "+" key to start counting the test
programme number upwards.
• Push the "i" to operate the boiler now and to start the
test programme.
• Push "i" and "+" simultaneously to exit the test
programs. You can also exit the test programs by not
pushing any button for 15 minutes.
50
Cause
Temperature difference between flow temperature sensor and
return temperature sensor too great -> flow and/or return
temperature sensor defective
Interruption/short-circuit of water pressure sensor, interruption/
short-circuit to GND in supply line to water pressure sensor
Line to water pressure sensor has short-circuited at 5V/24V
or internal error in water pressure sensor
Water pressure sensor and/or pump defective, air in heating
system, too little water in boiler; check adjustable bypass, connect
external expansion vessel to return
condensate pump defective, cable connection; no checkback signal
from flue gas flap (bridge) of "2 in 7" multifunction module, flue
gas flap has triggered
Communication error between display and PCB in the electronic
box
Display Meaning
1)
P. 0 Bleeding test program
The heating circuit and the hot water circuit are bled
via the automatic automatic air vent (the cap of the
automatic automatic air vent must be released).
1 x "i" button: Start bleeding heating circuit
(display view: HP)
2 x "i" button: Start bleeding charging circuit
(display view: SP)
3 x "i" button: Exit bleeding program
The heating pump is cyclically actuated
Note: The bleeding program takes about 6.5 minutes
to complete.
P.1 Test program, maximum load:
The boiler is operated at full load following successful
ignition and calibration.
P.2 Test program, minimum load:
The boiler is operated at minimum load following
successful ignition and calibration.
P.5 Test program, safety thermostat:
The burner is switched on at maximum output and the
temperature control is switched off so that the boiler
produces heat, bypassing a regular shutdown, until the
switch-off temperature of the safety thermostat is
reached (97 °C).
P.6 Test program, Diverter valve centre position:
(not active)
Table 9.5 Test programs
1)
Bleeding the boiler circuit:
Actuation of heating pump for 15 cycles: 15 s on, 10 s off.
Display view: HP or SP.
9.3

Resetting parameters to factory settings

In addition to the option of manually resetting the
factory settings for the individual parameters specified
in Tables 9.2 and 9.3, you can also reset all parameters
simultaneously.
• Change the value at diagnosis point "d.96" in
diagnosis level 2 to 1 (see Chap. 9.1.2).
The parameters of all adjustable diagnosis points now
correspond to the factory settings.
Installation and maintenance instructions ecoTEC 0020029173_01