Discussion in 'Plumbing and Central Heating' started by Mike 123, 27 Jan 2008.
Hi, does anybody know what the fault code F4 means?
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Ta very much, most helpful.
Better to say its the "F4" fault which is caused by a faulty non-black ignition unit.
Call Viessmann with the serial and postcode and they will send their service engineer to fix it for you within a day or two.
Unfortuanately they are not being proactive about this! Every boiler is going to fail and rather than being out in the open about the problem leave you to search in the dark.
As you know I will take issue with this, Tony.
The F4 fault can mean a whole raft of things, one of which is interference from the spark unit. Recently these have been modified it is true, but there were other PCB faults which cause F4 also.
The 100 series is not Viessmann's finest hour. Don't surprised if you get a new PCB (as well as a spark unit).
I have had a chat with a service engineer last week who is replacing about 5-6 every day and he says in his experience its nearly always the ignition unit which causes this and he has only changed a couple of PCBs during the last four months.
Of course F4 can be caused by any lack of ignition but practically the likelyhood is the ignition unit if its not the black one.
A failed PCB can give an F4 indication or explosive ignition.
I have the Vitodens 100, it is about 3 yrs old. I am having a great deal of difficulty with it at the moment. I would be grateful for your thoughts.
It started by running low on pressure say every 2 to 3 months, but we would top it up and away she would go. I then went away and turned her off, and she would not start when I came back. Displayed the f4 fault. By luck and persistence it eventually started working again.
However last week (Just before the heavy snow) it would not fire up, again displaying the f4 fault. The pressure was down, so I topped it back up, but it still would not start. I now have to leave the boiler on 24hrs a day, if it reaches the room stat temp and cuts off it will not restart.
I then have to top it up again. I have noticed that outside there is a discharge of water and the pressure has again dropped.
Could I have more than one issue i.e. the condensate needs cleaning out and the ignition unit needs replacing (mine is a greeny blue colour) and if so can someone tell where is best to get this part.
Basically I would be very grateful for anyones thoughts on this.
You should start your own thread rather than tagging on to an old one.
Its normal for the pressure to need to be topped up every 1-2-3-4 months. Your installer should have told you about tbis.
Your boiler may still be under warrantee. Even if it is not they might still replace or supply the ignition unit free. If your installer is a trained Viessmann installer that will help if the approach is made through him.
The F4 can be other causes apart from the ignition unit and an experienced CORGI engineer would be able to diagnose the exact fault.
You are expected to have had it serviced every year! Did you do that?
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