Fault Code – Vaillant Ecotec F70

Vaillant Ecotec F70

The meaning of this fault code F70 or F.70 according to the vaillant installation and servicing manual is as follows:

It is applicable to several vaillant models as well as some other brands of the Vaillant Group such as Glowworm. The main models are Ecotec Plus, Ecotec Pro, Turbomax, Ecotec Exclusive and a few more.

F.70 Cause

The cause of this error is usually that the PCB which is the same across many models has not been assigned it’s software identity for the model of boiler it is intended for. If the PCB is not assigned this number it cannot operate safely therefore it produces F70.

F.70 Solution / Repair

Once you have changed the PCB, enter the Installer Diagnostics menu or second diagnostic level. For older Ecotec models with the round dials, you press i button and + button at the same time. Then go to D97 using the – button, press i button once, so that you will see 00. Enter the code 17 using the + button, once reached, hold “i” button until it is accepted. The second diagnostic level is now available. Then proceed to D93 using the “-” button, press the “i” button to enter this value, change it to the correct DSN according to the table below. Finally hold the “i” button until it is stored and accepted. You may have to reset the boiler, and if this still doesn’t work, you may have to set to factory defaults using D96, setting it to 1, holding “i” so it accepts this. The boiler should then be reset back to defaults and it should no longer show D70 and start working as normal.

DSN (Device Specific Number) Table

The device specific codes are shown in the table below. You can search the table by model name, appliance type ie VUW and also search by the year. The appliance type code is the most accurate way of finding the exact DSN. We will add further appliance types over time.