Vaillant flue gas conveyor failure
This is just a bit of info regarding one of the issues you can have with the Vaillant ecoTEC, ecoMAX range of boilers which also include most of the Glowworms which are derived from the same design. Of all the components that can and do fail on Vaillant boilers, the flue gas conveyor is less common and is towards the bottom of the list of common problems.
The flue gas conveyor is essentially a plastic manifold which connects to the back of the primary heat exchanger.This transfers the flue gasses from that point up to the top of the heat exchanger where it connects to the flue. Due to the corrosive nature of the flue gasses this component has to be made of plastic and they do fail occasionally. A flue gas conveyor is typically something found on boilers that use primary heat exchangers based on the Giannoni heat exchanger design.
The images on this page are actually taken from a repair I did on a Vaillant ecoMAX 646 system boiler at a premises in Sheffield. This boiler is essentially a light commercial boiler installed in a large house and is not the boiler you typically find in a domestic property but is based on the ecoTEC/ecoMAX design.
This particular boiler hadn’t been serviced or looked at since it was originally fitted 6 years earlier. The conveyor had failed and as you can see from the corrosion in the photos the corrosive condensation had taken its toll on the boiler casing. If the customer had left this for another 12 – 18 months he probably would have had to replace the boiler.
When these fail the boiler will still continue to work, albeit maybe not entirely safely. You may notice a drip from the boiler when its running but apart from that you probably won’t notice a problem. When a gas appliance is running but doesn’t have sufficient oxygen to burn the gas, is when it will start to produce carbon monoxide.
When spent flue gasses are recirculated around a boiler internally and then recycled, means there is less oxygen and the appliance could start producing carbon monoxide. A failed flue gas conveyor is not good and is something that I check for whenever I service boiler of this design. If you have a steady drip from your boiler when its running it could be related to this or a condensate leak somewhere else.
This could mean the boiler isn’t working safely and you should get it looked at if that is the case. If you live in my locality and need your Vaillant boiler looking at I would love to help!
As an end user your only option is to call someone competent, qualified and Gas Safe registered to fix problems with your boiler(such as myself).
It is important to note that this is NOT intended to help other engineers and it is most definitely NOT intended as a DIY self help guide for homeowners trying to fix their own boilers.
If you are an engineer seeking information on how to fix this problem and this has been helpful in some way then thats great. However this page is for information purposes only and cannot be relied upon by someone attempting to carry out any repair – regardless of their qualifications. Read my disclaimer before attempting to use any information on this website.
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