Vaillant F28 Fault Code Repair

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 F28 Fault Code Repair

Models applicable to:

Ecotec Pro/Plus, Turbomax

F.28 Meaning

Failure during start-up: ignition unsuccessful

Causes

Gas meter defective or gas pressure regulator has triggered,
air in gas,
gas flow pressure too low,
thermal isolator device (TAE) has triggered,
condensate duct blocked,
incorrect gas restrictor,
incorrect ET gas valve,
fault on the gas valve,
multiple plug on PCB incorrectly plugged in,
break in cable harness,
ignition system (ignition transformer, ignition cable, ignition plug, ignition electrode) defective,

vaillant electrode 0020133816

ionisation current interrupted (cable, electrode),
incorrect earthing of boiler,
electronics defective

Solutions

1 . Check the gas meter has not been turned of accidentally or run out of credit if a prepayment meter. The number of times the gas lever has been found accidentally in the off or partially off position is surprising to clients.

2. You may need to press reset button upto 3 times just in case it is a one off occurrence or for the gas supply to re-estabilish. Make sure to keep an eye on future occurrences as this may show that are more deeper issues with the boiler that may require a heating professional to have a look at the boiler.

Ecotec Old F28 Reset Image — Vaillant F28. No 3 Reset Button

Vaillant Ecotec New Display F28 Reset Button — Vaillant Ecotec New F28 , No 3 Reset Button.

3. If the weather is extremely cold make sure your condensate pipe has not frozen or got blocked. When weather is normally, blocked condensate pipework can be cause by debris or blocked pathways further down the line

Disclaimer: Above video is by Worcester Bosch and some parts may not be applicable to your boiler.

4. Another common problem is the gas valve sticking due to the internal lubrication / seals hardening in cold weather, giving a the gas valve a gentle tap with a rubber object may allow it to free up.This technique can be improved by tapping while the boiler is in the process of ignition.Please note, this solution can only be carried out by a gas engineer as it requires the boiler case being removed in order to access the gas valve. Secondly as this is a gas appliance, it should only be done by a gas heating engineer.

5. Get a qualified gas engineer to check internal wiring and state of boiler

2 thoughts on “Vaillant F28 Fault Code Repair”

Hi good guidance but the man is actually standing front of the boiler so you can’t see the gas valve.

Jayesh Kanbi says:

January 12, 2025 at 3:37 pm

Hi, that is correct, as only gas registered engineers will understand what they are doing. Anyone who is not a gas engineer should not see this, otherwise they will copy the actions and we do not wish to be held liable for non registered people touching the gas valve, as one YouTube user stated they tried to do it themselves, instead they broke the gas valve and gas started leaking everywhere. So there is a clear disclaimer that we accept no liablity for any actions carried out be non registered people or damaged caused by registered or non registered. We are sincerely sorry this may not be to the liking of some home owners, however gas safety is paramount. This is strictly for the guidance of your engineer. We hope you understand.

Reply

Rukhsana says:

January 12, 2025 at 12:19 pm

Hi good guidance but the man is actually standing front of the boiler so you can’t see the gas valve.

1. Jayesh Kanbi says:
  
  January 12, 2025 at 3:37 pm
  
  Hi, that is correct, as only gas registered engineers will understand what they are doing. Anyone who is not a gas engineer should not see this, otherwise they will copy the actions and we do not wish to be held liable for non registered people touching the gas valve, as one YouTube user stated they tried to do it themselves, instead they broke the gas valve and gas started leaking everywhere. So there is a clear disclaimer that we accept no liablity for any actions carried out be non registered people or damaged caused by registered or non registered. We are sincerely sorry this may not be to the liking of some home owners, however gas safety is paramount. This is strictly for the guidance of your engineer. We hope you understand.