F4 FAULT CODE – Viessmann gas boiler. How to reset. Viessmann Vitodens 100 fault codes.
Today I’m going to look at the F4 boiler fault. This is the Viessmann boiler. This particular boiler is a Viessmann Vitodens 100 combination boiler, of combi boiler. And at the moment it’s got an F4 fault on it. So, what I’m going to do is I’m going to go through the F4 fault, and show you what you can do to repair it.

Most of the time, or a lot of the time, this will be you will need a gas engineer to repair this. But there are some simple things that we can check first of all. So, yeah, first of all what we’ll do is we’ll reset the boiler. So, come in now, I’ll show you how to reset it, and then you can see if that will fix it. If that fixes it, then happy days. And then we’ll go further into it, and I’ll show you some more reasons for the F4 faults code. So, yeah, let’s have a look now.

If you are getting this F4 fault code, I would advise that if you haven’t had your boiler serviced for a while, then you call an engineer out and get your boiler serviced. But I’ll show you how to reset the boiler now. If we have a look on here, we can see the reset symbol. I’ll show you how to do that now.

All we need to do is put it into the reset and then we just turn it back quickly and it’ll just reset. If you struggle to do that, I will also show you another option. So, I’ve put it back to F4. And if you’ve tried to do the rest and you can do it, or you’re struggling, then you can just turn boiler off. And most of the time it’ll come back on again and it’ll reset. It’ll probably still go back into your fault code, so now you need to find out what the faults are.

There’s a couple of things, or there’s quite a few things to check. One thing to check is the gas. What we’ll do is we’ll have a look underneath now, and I’ll show you where the gas tap is on it. On this particular boiler, the gas tap is yellow. And this one, this one’s actually turned off. So, if we turn it back on there then this boiler would work again. But there’s other reasons that it could go faulty as well, so with regards to the gas part of it, what you’d need to do is just check that if you’ve got a gas token metre for instance, that you haven’t run out of gas. It may be that somebody’s knocked the lever off your gas metre. So, that’s a few things to check with the gas metre.

Also, it could be your condensate pipe. So, if it’s cold weather outside, it could be that this pipe here is frozen. So, where it goes to outside, it could be frozen. What you could do with that is these videos, how to unfreeze your condensate pipe. So, that might be something that you’d be able to do. It could also just be blocked, so if it’s a pipe like this, you could just pull it out, and you could just check that it’s okay. And then just put it back in.

And then what we’ll do is we’ll have a look inside as well and I’ll show you some options or some things it could be inside as well. Just to remember, if you’re going to take the case off on a boiler, you must be gas safe registered. This is part of the seal of the boiler, so we’d do our safety checks first, and then once we’ve took the cover off, what I’ve done in here, there are some other issues. So, I’ve actually turned the gas back on and we’ve got another F4 fault. And what I’ve done with this now, I’ve just removed the lead. So, what that tells us, if we have a problem with the ignition, if we had a problem with this ignition, that’s another reason that we could have an F4 fault. So, it may be that it needs new electrodes. It may be the boiler just needs a service. I’ve seen them inside before where they’ve got loads and loads of muck inside and it just won’t work very well. So, that’s another reason.

It’s very important, very, very important that you have your boiler serviced. As I say, it could be electrodes on this. There are a few other reasons, but they’re the normal basic reasons. Yeah, I hope this video was of some use, and thanks for watching.

Allen Hart

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