Vaillant 837 question - d.000 setting

[ezman]

Hi,

Been having a few issues with my new boiler not going full pelt when heating clicks on. It stays on a low flame without properly going for it.

So I call Vaillant who guide me to this setting d.000 and tell me to switch it from Auto to 28kw.
Now that did the trick, he said that auto sometimes plays up as it tries to range rate itself.

My question is what are the implications of having changed this setting?

Will it still work efficiently or will it always want to work at full pelt regardless of the work it has to do. Sorry if this makes no sense, just want to make sure gas bills don't get wild.

 

[billybob150811]

your gas bill wont go wild. if its left in auto it has a learning programme and it can play up by setting it to 28kw it will still modulate as it should

 

[Riley]

As mentioned it's just an intelligent feature whereby the boiler will learn your system and fire accordingly.

 

[ezman]

Thanks both, so should I switch it back to Auto for longer and give it a chance rather than on 28kw? The vaillant guy just went straight for the 28kw option.
Also, and I know that I'm going out of my depth here, but is there any worth in setting it down to say 18kw at times of low heat requirement? I think the best answer is leave it alone, but curious anyway.

 

[Riley]

Why has your installer not set it up properly. With the greatest respect you're changing settings you don't understand

 

[ezman]

Hi, I phoned Vaillant as there was an issue with it not coming on full heat and that's what they told me to do, however you're right in that I did change a setting I didn't understand...but the manufacturer asked me to do so.

 

[Riley]

No I understand you did as instructed just wish people would set these up properly at commissioning

 

[doitmyself]

Will it still work efficiently or will it always want to work at full pelt regardless of the work it has to do.

Yes, it still work efficiently
No, it will not always work at full pelt.

The auto feature is supposed to set the maximum output of the boiler to meet the requirements of the installation. The boiler will still modulate between minimum and maximum depending on the requirement at the time, e.g. how cold it is. Vaillant are now admitting that the auto feature doesn't always work correctly.

I don't know how they arrived at the 28kW setting as it depends on the heat loss of your house, and 28kW implies a large house with a high heat loss. You may be able to reduce the maximum output even further. Use Baxi Whole House Boiler Size Calculator to estimate the heat loss of your house and set the boiler output to this.