Vaillant F28 Fault Code Repair
Models applicable to:
Ecotec Pro/Plus, Turbomax
Failure during start-up: ignition unsuccessful
- 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
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.
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. Please note, this solution can only be carried out by a gas engineer as it requires taking of the boiler case in order to access the gas valve. Secondly as this is a gas carrying item, it should only be done by a gas heating engineer. This technique can be improved by tapping while the boiler is in the process of ignition.
5. Get a qualified gas engineer to check internal wiring and state of boiler
Statistical Chances of Faults:
Following are the likely chances of certain faults from high to low.
~39% chance of the gas valve being at fault.
~32% chance of the gas supply being at fault
~28% chance of other reasons causing the fault
Preventing frozen condensate pipework:
There are a few solutions to solving frozen condensate pipework. These are as follows
- The best solution is to make sure discharge pipework is run internally if possible.
- If run externally make sure it is of large diameter pipe size ie 32mm and 40mm (insulated if possible or required)
- Insulate smaller pipes with suitable exterior grade insulation
- Use trace heating if required and installed according to the trace heating manufacturers recommended instructions.