General question about Vaillant Ecotec boiler and system settings.

[Mottie]

Vaillant Ecotec plus 418. With the cold weather almost gone I was wondering whether it would be advantageous to adjust my boiler and system settings. As the heating has been rarely used lately, I’ve changed the pump speed from medium to low - about the only rads on are the bathroom and lounge. When I did this I also had to adjust the auto bypass valve as the low pump speed didn’t have the oomph to make the valve open when system was on the overrun. Now I know it’s okay as I can feel the bypass pipe getting hot when this happens. I was also wondering if it is worth adjusting the boiler maximum output to say 12kw to save wear on the boiler in the summer as it will just be heating the hot water cylinder? Would it save any wear by not working at max output?

 

[OvertonPlumber]

Stop fooling around with it put the pumpspeed to 2 or 3 as you will cause more problems with the hex as they are prone to issues.

 

[Mottie]

Stop fooling around with it put the pumpspeed to 2 or 3 as you will cause more problems with the hex as they are prone to issues.

More problems - I haven’t got any problems so how could I have more of them? What issues are they prone to - it’s only a couple of years old.

 

[DP]

Mottie, let the boiler controls do what they are designed to do.

 

[Mottie]

Mottie, let the boiler controls do what they are designed to do.

Aren’t the boiler controls designed to do what they are set to do and be adjusted to suit the requirements? If not, why not just send them out with one boiler temperature control knob instead of all those different settings?

 

[DP]

The control at the front of the boiler ( user adjustable) is there to set the flow temperature suited for you cylinder and heating ( will need to be high enough to achieve what has been set on the cylinder thermostat with heating going off when room-thermostat switches off ). By all means set it to what you want. Lower setting will make the boiler run more efficiently ( condense more) but may not achieve required load temperatures

Pump speed is preset to achieve required temperature differential. Slow the speed down, heatup time will be effected, boiler may start to cycle more, go into overheat area even.
Bypass should only open when there is no circulation. You start tinkering with these settings- you may improve or ruin what you have at present.
If you start to adjust boiler output, cylinder, if UV, will certainly take longer to reach required set temperature

Series 4 at times is a fickle boiler that sometimes suffers from flow issues not known when series 6 or 8 are doing the task. Playing with pump speed etc could open a can of worms.

 

[Mottie]

Thanks DP. I did have the pump on low speed last summer when only heating water but as it got colder I found I had to switch the pump up a notch to help the heat up time. I’ll do the same this summer but I was just thinking that it might be better to have the boiler not going at full pelt to just heat water in my unvented cylinder. Also, with a slower pump speed it will help to have a lower setting for when the pump goes into overrun. I could even adjust the pump to run longer if required - 7 mins instead of the preset 5? Vaillant do a 12kw ecotec plus boiler and presumably that will be sufficient to heat a tank of water so I’m sure that if I set mine to max 12kw it will heat my 150 litre cylinder of water. I’m in no rush to heat it as I leave my hot water permanently on.

Surely they make them adjustable for a reason and I just can’t see why it should remain on the same settings that I need to heat a whole house with 10 rads and hot water in mid winter as I do for heating just hot water in summer.

I suppose I can only give it a try and see what happens. I think a lot of it is trial and error as circumstance must vary from house to house. if it starts cutting out and overheating I'll soon know that something is wrong!

 

[Gasplumber]

Yeah there’s an argument for if my boiler self modulates why can we adjust the max kw. And if we do does it actually work since the boiler is self modulating!