problem with Vaillant Turbomax 828 firing up

[barnsleyfan]

When i turn on my hot water tap it can take anything between 2 seconds and 5 minutes for the boiler to ignite. As soon as i turn on the hot tap the boiler makes a noise and the green light flashes. You can hear the iginition firing away but it doesn't usually light. Sometimes it will eventually light and the yellow light come on, but immediately (less than a second later) go out. Eventually it will light. However, often it will then go out whilst filling a bath. Due to the length of time it takes to reignite, the water goes cold before it relights. As mentioned, sometimes the boiler lights within a few seconds, but the occurence of this is getting less often. Typically it will now take at least a minute to fire up.

After searching this forum I suspect it could be the APS, but would this explain the intermittentness, or would it always not work if it was the APS.

I once had a Vokera boiler with a similar problem, which I could force to ignite by opening the back door (boiler sited in kitchen) oe blowing down a vent near the top of the boiler. But such tricks do not work with this boiler.

Thanks

 

[Agile]

It might well be the APS and just in th case of your boiler you can replace it yourself.


However, a reg gas engineer should really be called to service the boiler and identify the problem.

Its recommended that boilers are serviced every year! When was yours last done?

Tony

 

[barnsleyfan]

it was service a few months back when it wasn't too much of a problem. My concern is that someone will come out and it will work OK whilst they are there because the fault is intermittent.

Is the APS something that can be tested to see if it is functioning properly

 

[Boilerman2]

I would not recommend DIY replacement of an APS, it is a safety related control it should be considered that the APS might be doing it's job, you may have a flue of fan fault it isn't always the case that the APS is the cause of the fault get a registered Gas Engineer to have a look
p.s. a good engineer will be used to dealing with intermittant faults

 

[Agile]

The APS on your model is a common failure point.

It can be tested by measuring the contact resistance when it is operated by gently blowing towards to inlet (+) tube connector.

That should be less than one ohm when its repeated several times.

I am only advising you of this because the APS is mounted externally to the combustion chamber on your model.

Normally they are inside where a DIYer should not be accessing.

Tony