combi boiler keeps on turning on

Hi - not sure if there is anything wrong with my boiler or not. i have a vailant combi boiler and no matter what heat setting it is at it comes on for a while with the burners going, seems to turn off and then starts straight back up again - continuously. I thought that it would keep on till it had reached the temp and then just keep blasting as and when needed - not keep going on and off the whole time? Any help would be appreciated. Thanks Debbie

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What model and how often does it come on and off? I mean, they are meant to turn off when the CH is up to temperature, then they come back on when the temperature drops, so it would help if we knew exactly what its doing.
Andy.

On 17 Dec 2006 04:59:23 -0800 someone who may be "debbieg"
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How does it "seem to turn off"?
Do you mean that the burners turn off? When they turn off the pump will probably still be running.
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After how long?
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For how long?
Depending on the times this could be caused by a variety of things. For example some combination boilers have a hot water reservoir that they keep warm by intermittent firing. We will have more chance of guessing what it is with more information.

On Sun, 17 Dec 2006 04:59:23 -0800, debbieg wrote:
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What model? A stock fault on the VCW 242s is that the main PCB (the hardest to change) goes down with a fault that causes the CH to run continously.

Hah, I had a Vaillant which I replaced with a Halstead. This is almost exactly the opposite of the fault I have at the moment (random tripping and locking out). When I find out what is wrong I will post the answer; good luck!

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If you have a wireless programmer/thermostat, check the batteries in it. We have an Alpha boiler with wireless programmer/thermostat and if we happen to miss the low battery indicator on it (which is easy to do) the boiler goes into a sort of a hard-coded "failsafe" (I know that's not the phrase I need but can't think of anything better at the moment) 2 minutes on, 9 minutes off, cycle - and continues like that until the batteries are replaced.
JellyBelly

JellyBelly wrote:
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I have a Vailant combi boiler, it does this at odd times through the day, even when CH is switched off and no hot water is being drawn. when it was installed the installer told me this would happen as it keeps a small reservoir of hot water. Not sure of the model, if it is important I can root through my boxes and find out.

On Mon, 18 Dec 2006 17:25:01 +0000, Broadback wrote:
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Yes some models have the ability to do this. In general, to keep the boiler in warm standby is about 30s every 30 minutes.
The OP was having the boiler run more than that.