Vaillant ecoTec Plus 418 D0 Setting

[Dunbar]

Could anyone please provide an idiots guide how to change the D0 setting on my boiler. When I open the panel I'm faced with four buttons Bottom two + and - top two - -. That would be a great starting point.

My D0 setting is apparently D00 (auto) and to cut a long story short, my boiler has changed in the way it operates. It now takes around 6 mins to fire up instead of less than 1 min, and the flame is not as strong. Vaillant have changed my pcb under extended warranty and it went back to working how it was but only for for 10 days, and now has slipped back to a quieter slower mode of operation. Doing a bit of research tells me that D00 is not always the best setting, and that I should be adding up my rads and x 1.5. That would mean by D0 setting for me should be around 14kw. It looks like it might be worth a go at setting D0 to that. However any views would be appreciated.

 

[Scott_D]

Have you got the owners manual?

 

[Dunbar]

Have you got the owners manual?

I have the Installation and instructions booklet and Installation manual, but can't find how I access the menu, select what I want to change, or how to change it.

 

[John.g]

This may only be accessible at installer level?.

You seem to have ongoing problems as you shouldn't really have to range rate a boiler IMO......

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When you say it takes 6 mins to fire up do you mean that it sits there for 6 mins after pressing the start button or takes repeated cycles to get to this minimum flame symbol which might be ~ 5kw?.
Have you got outside temperature compensation control or just local control of the boiler flow target set point) temperature control?.

 

[Dunbar]

Thanks for your quick reply. When the boiler is called to come on (e.g. from room stat) the rad symbol immediately appears. After a short while it then starts to flash and the flame symbol appears with the flame at the very bottom. Then for the next 6 mins the temp either remains static or moves up a couple of degrees. Then after 6 mins you can hear the boiler fire up and the temp then climbs. Flame is around half way up on the symbol

Before this started to happen, the time between the rad symbol flashing and the boiler firing was less than one minute, and the flame was higher and louder. As I said Vaillant sent an engineer out and he fitted a new pcb. The boiler worked for around 10 days as it did before the change happened, but has now fallen back to how it was. I haven't got outside temp control btw.

 

[John.g]

If its the flow temperature that remains static or moves up a little then the boiler will not fire, it will fire up when the the flow temp is the target temp (65C?) minus 5C, or 60C, the temperature should fall fairly rapidly except that the circulation pump isn't starting immediately on boiler request, have you a system boiler with internal circ pump or is the pump external?.

Also check that d.17 is 0 and not 1 which is return temperature control.

 

[Dunbar]

If its the flow temperature that remains static or moves up a little then the boiler will not fire, it will fire up when the the flow temp is the target temp (65C?) minus 5C, or 60C, the temperature should fall fairly rapidly except that the circulation pump isn't starting immediately on boiler request, have you a system boiler with internal circ pump or is the pump external?.

Also check that d.17 is 0 and not 1 which is return temperature control.

OK John thanks. Flow temp 75% as advised by Vaillant. When it is triggered to come on the temp is usually around 30 or below, When rad symbol is flashing it sometimes climbs up a degree or two, then stays there until boiler fires after around 6 mins. Pump is in airing cupboard set at 2 with cylinder and diverter valve. Everything is working fine, but boiler is just taking longer to fire and is much quieter. Wonder if I'm being too fussy, it's just that the boiler changed the way it operated. I just thought of the d0 setting as something to try. The change happened around the time the boiler was serviced, so I'm wondering if any settings were changed then. Noted your comments about d17, but still not sure how to get into that when I open up the panel.

 

[John.g]

The rad symbol starts flashing when there is CH demand, the circ pump starts immediately, the rad symbol will remain flashing if "the boiler is hot enough" which I presume in your case is = or > 60C which it clearly isn't so if that rad symbol is still flashing for 6 mins before the boiler fires then something clearly wrong, its certainly not normal operation.

Is there a tap symbol for hot water and how does the boiler behave with HW selected or is it the same symbol and motorized valve(s) c/o on HW demand?.

I see you have a diverter valve so does rad symbol flash for 6 minutes also when HW selected?
Also just check with your hand if circ pump starts immediately when any heat demand called for.

 

[Dunbar]

The rad symbol starts flashing when there is CH demand, the circ pump starts immediately, the rad symbol will remain flashing if "the boiler is hot enough" which I presume in your case is = or > 60C which it clearly isn't so if that rad symbol is still flashing for 6 mins before the boiler fires then something clearly wrong, its certainly not normal operation.

Is there a tap symbol for hot water and how does the boiler behave with HW selected or is it the same symbol and motorized valve(s) c/o on HW demand?.

I see you have a diverter valve so does rad symbol flash for 6 minutes also when HW selected?
Also just check with your hand if circ pump starts immediately when any heat demand called for.

Yeah, it's exactly the same when the boiler comes on to heat the water. I have a tap symbol, but it's the rad symbol again which flashes for the hot water. Just flicked the room stat on and pump comes on immediately.

 

[John.g]

Can't see why you can't at least access the d codes as there are numerous posts re the householders changing the parameters including d.0, it must be relatively simple to do this and allowed by vaillant.
If the boiler wasn't serviced since the extended warranty work (PCB etc) then they should return to fix it and even if it has been serviced except they find something seriously set wrong should still honour the warranty.
Why not, at least, give them a buzz?.

 

[Dunbar]

Can't see why you can't at least access the d codes as there are numerous posts re the householders changing the parameters including d.0, it must be relatively simple to do this and allowed by vaillant.
If the boiler wasn't serviced since the extended warranty work (PCB etc) then they should return to fix it and even if it has been serviced except they find something seriously set wrong should still honour the warranty.
Why not, at least, give them a buzz?.

Was trying to avoid another call out, but still have three years left on the warranty so will. re adjusting, I've opened the flap and pressed both top buttons and the screen just lights up. Have a feeling that to get the menu you press both top buttons together and then can scroll though, but don't want to f anything up. That's why I asked in the OP if anyone could guide me through.

 

[ShaunCorbs]

 

[Dunbar]

Cheers Shaun.

 

[Dunbar]

Changed setting from Auto to 14kw. Didn't fix it. Changed it back to Auto, turned it on and and it went off like a train. Now I'm really confused. Have a feeling that it won't last.

 

[John.g]

These Vaillants have a bit of a mind of their own I suspect.
Next time you are in the menu have a look at d.01 the pump overrun time and d.02. d.01 has a default time of 5 minutes and the anti-cycling time has a default setting of 20 minutes but the actual time depends on the boiler flow target temperature, at 65C it is 4.5 mins and at 60C is 6 minutes so presumably as long as the boiler has been stopped for either a total of either 5 minutes or 9.5 minutes then it should fire up immediately on request?.

 

[Joniboy]

Any joy with this , I have same problem