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Fault Code – Vaillant Ecotec F70

Welcome to the fault-codes section of this site. The following table or page contains the information required to help repair and diagnose the fault codes being shown on the boiler display. You may be guided through the fault finding sequence or steps, for rectifying your boiler with this fault code. Suggested repair solutions may be provided by a link to a repair page. NB Some fault codes are only applicable to a specific range of boilers only.

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.

ModelAppliance TypeYearAppliance DSN
Ecotec Plus 6122005-20120
Ecotec Plus 6152005-20121
Ecotec Plus 6182005-20122
Ecotec Plus 6242005-20123
Ecotec Plus 6302005-20124
Ecotec Plus 6372005-20125
Ecotec Plus 8242005-20126
Ecotec Plus 8256
Ecotec Plus 8312005-20127
Ecotec Plus 83210
Ecotec Plus 835VUW 306/5-5 H-GB62
Ecotec Plus 8372005-20128
Ecotec Plus 83817
Ecotec Plus 9372005-20128
Ecotec Plus 93810
Ecotec Exclusive 8322007-20164
Ecotec Exclusive 8382007-20165
Ecotec Plus 4152006-201511
Ecotec Plus 4182006-201512
Ecotec Plus 4282006-201513
Ecotec Plus 4382006-201514
Ecotec Pro 242005-20127
Ecotec Pro 282005-20120
Ecotec Pro 242012-20157
Ecotec Pro 282012-20158
Ecotec Plus 612 (VU GB 126/5-5)2012-20151
Ecotec Plus 615 (VU GB 156/5-5)2012-20153
Ecotec Plus 618 (VU GB 186/5-5)2012-20154
Ecotec Plus 624 (VU GB 246/5-5)2012-20159
Ecotec Plus 630 (VU GB 306/5-5)2012-201514
Ecotec Plus 637 (VU GB 376/5-5)2012-201520
Ecotec Plus 824) (VUW GB 246/5-52012-20156
Ecotec Plus 831 (VUW GB 316/5-5)2012-201510
Ecotec Plus 837 (VUW GB 376/5-5)2012-201517
Ecotec Plus 9372012-201517
Ecotec Plus 612 (VU GB 126/5-5 A)2015-1
Ecotec Plus 615 (VU GB 156/5-5 A)2015-3
Ecotec Plus 618 (VU GB 186/5-5 A)2015-4
Ecotec Plus 624 (VU GB 246/5-5 A)2015-9
Ecotec Plus 630 (VU GB 306/5-5 A)2015-14
Ecotec Plus 637 (VU GB 376/5-5 A)2015-20
Ecotec Plus 825 (VUW GB 256/5-5)2015-6
Ecotec Plus 832 (VUW GB 326/5-5)2015-10
Ecotec Plus 835 (VUW GB 356/5-5)2015-13
Ecotec Plus 835 (VUW GB 356/5-5)13
Ecotec Plus 838 (VUW GB 386/5-5)2015-17
Ecotec Plus 9372015-17
Ecotec Pro 24 (VUW GB 306/5-3)2015-7
Ecotec Pro 28 (VUW GB 306/5-3)2015-22
Ecotec Pro 30 (VUW GB 306/5-3)2015-26
Ecotec Plus 46KW Old Type (VUW GB 466/4-5 H)Pre 201246
Ecotec Plus 46KW Old Type (VUW GB 466/4-5 A)Pre 201246
Ecotec Plus 65KW Old Type (VUW GB 656/4-5 H)Pre 201247
Ecotec Plus 65KW Old Type (VUW GB 656/4-5 A)Pre 201247

Disclaimer: Information on this website is provided for informational purpose therefore we cannot accept liability for subsequent problems. All repair tasks should be carried out by qualified trades people. We may also receive commission payments when you are taken to external websites and complete purchases from third party sellers, once you leave our site, we cannot be held liable for your purchases.