Vaillant Ecotec 418 - fault code f23 and F24 help

29 Aug 2010
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United Kingdom
I have an vaillant ecotec boiler installed approximately 2.5 years ago. The boiler has a magna cleaner attached to it when fitted.

The boiler will fire up for a while and then error codes F23 or F24 will appear. if you rest the boiler, the boiler will work for a while then code appears again. Acording to the manual it - water shortage, temperature rises too quickly.

Could someone please advice what is the best way to resolve this. How much would it cost to repair the boiler.

thank you in advance.
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For whatever reason there isn't enough water flowing through the boiler to carry off the heat being generated.

It could be a failing pump or some sort of restriction in the pipework

Is the pump set to it's highest speed?
The flow rate thru the 418 heat exchanger can cause problems because of the small waterways in this boiler. Volume installers aee aware of the problem, best fix is not to fit one on an existing system.

Water flow rate is key. If you have an auto bypass open it at bit more, and as suggested, wind up the pump speed. Check the mag filter is fully open on the valves and not blocked.
Thank you for your replies.

The pump is set to the maximum speed of 3 & this was a new pump installed last year. I will check the other points mentioned.
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Since the boiler was installed how many times has the mag filter been cleaned and each time how much dirt was removed?

It always amuses me to see them being fitted but no regime being put in place for regular cleaning.

Hi Tony
The magna cleaner is cleaned every 4-6 months. it was last cleaned end of September and had some dirt. The system was power flushed last October.

Our last boiler potterton last for a number of years and did not cause this many problems.
Hi Tony
The magna cleaner is cleaned every 4-6 months. .

no where near enough! 4-5 weeks, not months until you see no dirt in the magnaleak!

the other issue with magna's is not getting the crud out of the bottom of them. at least with a TF1 you can empty them! as others have said, most likely the H/E is full of crud. i've had at least 2 that have needed removing and flushing even though a full flush was done prior to install.
Hi dboiler

Did your boiler settle down eventually? How was it solved? I keep having similar problem - F23 fault code system shut down

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