Vaillant Turbomax 828 Intermittent F.28 When Cold

[fluorescence]

Hi all,

Just wondering before we throw more money at this boiler if anyone has seen this issue before. I already know that F.28 is failure to ignite, and I have witnessed this happen a couple of times now. Note that this *only* happens when the boiler has not been used for several hours and it is cold..

When heating or hot water is called, the boiler fan & pump comes on as normal, I hear the click of the gas valve and can see the igniter sparking through the peep hole with the outer casing removed. The boiler attempts to ignite three times for several seconds each time before the F.28 lock-out happens.

Usually when cold the boiler will ignite on the second or third attempt, but sometimes it fails and locks out on F.28 and will not strike up again until I reset it. Once the boiler does eventually ignite from cold, it goes with quite a 'woosh'! Once the boiler has warmed up a bit, it'll run happily all day long & will shut down & re-ignite without an issue.

We have recently had the entire central heating system re-plumbed which should not affect the gas side of things. We have already had the electrode & flame sensor replaced as the flame sensor was getting slow to react.

Yes I know I need a Gas Safe engineer out to it, but I'd like to know what to expect first. I don't want to throw too much money at this old-ish boiler ideally, but also cannot afford a new one right now!

 

[Agile]

Hi all,

We have already had the electrode & flame sensor replaced as the flame sensor was getting slow to react.

Yes I know I need a Gas Safe engineer out to it, but I'd like to know what to expect first. I don't want to throw too much money at this old-ish boiler ideally, but also cannot afford a new one right now!

So who replaced these parts? You ?

Should have been by an RGI who might know how to diagnose the cause of the F28.

In my experience usually a 100 pound part or a free fix by others! That's assuming the boiler is already set up correctly.

 

[fluorescence]

So who replaced these parts? You?

I did the re-plumb, flow and return pretty much all replaced (in copper) along with new rads. I also fitted a new diverter valve. A friend of a friend who formerly worked for British Gas then fitted the new igniter. They also serviced it and checked gas pressures etc which were all fine.

...RGI who might know how to diagnose the cause of the F28

'might' being the key word there. One person is less likely to know than the hundreds (or so) of people here who see this, hence why I'm asking before getting someone out to it. Lets face it, being gas safe registered doesn't automatically make a person a genius who knows every thing about every boiler ever made. I don't just want to have to throw parts at it until it works, with me paying £££s for said parts (and the labour) obviously.

In my experience usually a 100 pound part or a free fix by others! That's assuming the boiler is already set up correctly.

The boiler should be set up correctly. One would assume the part you're referring to is the gas valve, but I'm not Gas Safe registered & am a mere commercial electrician so what would I know?

 

[ianmcd]

if you have another gas appliance say a hob or cooker, when the boiler is not lighting see if you have gas at another appliance, it is common for meter regulators to stick at this time of year if you have gas at the other appliance then it is indeed your boiler and most likely the gas valve, if you dont have gas at the other appliance it is indeed the meter regulator and your supplier will replace it free of charge

 

[fluorescence]

Many thanks. The gas goes to the boiler only, and is only a short run of about 2 metres from the isolator valve outside. It's worth mentioning this pipework is only 15mm which I'm lead to believe is on the small side, but it's never been an issue before so can't think it's suddenly an issue now?

We're on a Calor LPG tank, do the regulators in these have problems with sticking too?

 

[ianmcd]

That was something that you should have mentioned from the very start, no your pipe is definately not too small, it could be a fault with the supply but most likely the gas valve on the boiler you need a RGI qualified to work on LPG to sort it