Vaillant ectotec Cycling Problem

[Agile]

You seem to have set the flow temp to just 68 C.

In this weather you need it at about 75 C otherwise it will take ages to reach the room stat temperature as you have found.

As far as I can see your boiler is working correctly but just cycling because its seriously over rated for the house heat loss.

There ar many heat loss calc programs but most do not work well with mixed construction methods.

Tony

 

[Broards]

Argile - ok turned it up to 75 and will turn it down to 10 kw tonight

Thanks

 

[Jamer]

Hi, read your posts with interest. I have the same boiler with the same problems. Our house is 220m2. But, we don't use about a third of the house much. when we have guest we would like to heat all of it if needed, so we bought a boiler to match. We have no wall insulation and the house leaks quite a bit. We're in the middle of a refurb. If you go to the valliant web site, it says our consumption is between 20 and 34 kw, depending on what parameters I put in. Including making the house smaller and well insulated. It always says the 428 is the right size boiler. We have 5 rads that run on microbore and 7 that run on 15mm. All rads get very hot. The heat difference is usually about 17c at the boiler. I've had the valliant guy in and whilst he was very nice I got the feeling that he thought I was a bit weird for wanting a boiler that would bang out lots of heat sometimes and modulate at a lower temp when I only want a bit. Is that too much to ask for? It seams reasonable to me. We've dialled back the boiler to 18kw. It's better, but, the anti-cycling controls the house temp rather than the thermostats. Surely this can't be right. I'll try knocking it back to 10kw, but from what i understand its going to affect efficiency a lot, which is one of the reasons I bought it. Sorry to rant but i seam to spend all my time wrestling my boiler trying to get it to do what it should anyway.

 

[petertheplumber12]

Hi, read your posts with interest. I have the same boiler with the same problems. Our house is 220m2. But, we don't use about a third of the house much. when we have guest we would like to heat all of it if needed, so we bought a boiler to match. We have no wall insulation and the house leaks quite a bit. We're in the middle of a refurb. If you go to the valliant web site, it says our consumption is between 20 and 34 kw, depending on what parameters I put in. Including making the house smaller and well insulated. It always says the 428 is the right size boiler. We have 5 rads that run on microbore and 7 that run on 15mm. All rads get very hot. The heat difference is usually about 17c at the boiler. I've had the valliant guy in and whilst he was very nice I got the feeling that he thought I was a bit weird for wanting a boiler that would bang out lots of heat sometimes and modulate at a lower temp when I only want a bit. Is that too much to ask for? It seams reasonable to me. We've dialled back the boiler to 18kw. It's better, but, the anti-cycling controls the house temp rather than the thermostats. Surely this can't be right. I'll try knocking it back to 10kw, but from what i understand its going to affect efficiency a lot, which is one of the reasons I bought it. Sorry to rant but i seam to spend all my time wrestling my boiler trying to get it to do what it should anyway.

I believe you can input an anticycling mode I think it is S28. There is also a D82 trouble shooting display for cycling in heating mode.
Do you get the d82 shown when you press the I for info button?

 

[ALEC1]

I would have a look at this:

http://vaillantcyclingproblem.blogspot.co.uk/?m=1

 

[petertheplumber12]

I used to have a very high opinion of vaillant boilers, but now they are condensing boilers I have changed my mind and my next boiler which is in a couple of months time is going to be an intergas boiler.

 

[ALEC1]

Vaillant boilers with compensation controls are as good as the get...the 400 series is a UK boiler only, and Vaillant is a responsable company that knows the market and what is needed.

The trouble is the boilers are developed for compensation controls and we insist we know better by turning things on and off...

 

[ALEC1]

ok well not the 400 series.. which seems to have emanated from a UK design house...

 

[petertheplumber12]

How ever right you are alec the truth is I get customers complaining to me when the boiler does things they don't expect, and it is hassle that I don't need that is not my fault. However right the MI is.

 

[Jamer]

Pete and Alec
Thanks for feedback. I hope we (valliant, my guy and I) can work this out. But should we have to and should I have to do crash course in boiler design theory when all I want is reliable, predictable and controllable heat.
Thanks again and I'll check the link.

 

[Broards]

Jamer, I agree that all we consumers want is something that works. I, like you I suspect, i never knew how complicated this stuff is. I have a new found respect for talented heating engineer and I'm sure the competent ones are upset with the poor standards offered by some. If your house is over 100sqm more than mine and I have a timber frame with wall insulation / part new extention with upto date building regs how can we need the same boiler ?

Spoke to my builder the other day who continues to happily tell me that all is well as the boiler is oversized. I asked his plumber about boiler modulation and I got a blank look ! That told me a lot.

Vaillant specific issues a side, it seems to me that the boiler sizing is a complex issue that is critical to the whole thing as without it the system either cycles all the time or its never efficient.

Have you had calculations done on the house ?

Can anybody tell me the options for these calcs ie is there a lazy way and a competent way to do it. How do you all you heating engineers do your calcs ?
As I'd like to have mine redone, taking on board previous posts about the make up of my house.

 

[Agile]

Spoke to my builder the other day who continues to happily tell me that all is well as the boiler is oversized. I asked his plumber about boiler modulation and I got a blank look ! That told me a lot.

I can never understand how householders can listen to rubbish from builders and think that they are heating experts.

No good heating engineer is ever likely to work for a builder. All they want is a cheap plumber do do work for them.

[ Have you realised there is a difference between a heating engineer and a plumber? ]

 

[b13kal]

Spoke to my builder the other day who continues to happily tell me that all is well as the boiler is oversized. I asked his plumber about boiler modulation and I got a blank look ! That told me a lot.

I can never understand how householders can listen to rubbish from builders and think that they are heating experts.

No good heating engineer is ever likely to work for a builder. All they want is a cheap plumber do do work for them.

[ Have you realised there is a difference between a heating engineer and a plumber? ]

I have not come across a builder that don't want cheap work. You give them the advise, they don't want to hear it. They want cheap and cheerfully with YOUR name on it . I don't work for them, not putting crap on my name

 

[Broards]

Argile, yes I have. As per my last post I have so much more respect for a proper heating engineer than I have ever had before (and i'm now learning the difference). In life you live and learn about things. Being too green we placed too much faith in the re assurances of the builder that we had a good plumber / heating engineer. How wrong could we be ? Very. I'm just glad that there were other things in the build that we too much more control over. Thanks for all your help by the way.

I still have not paid the final payment so I hope i still have a chance to sort thing out. The builder saying I just wont pay. But the reality is I'm happy to pay I just want it to be done right.

 

[Agile]

Pete and Alec

Thanks for feedback. I hope we (valliant, my guy and I) can work this out. But should we have to and should I have to do crash course in boiler design theory when all I want is reliable, predictable and controllable heat.

Of course you should not !

But unfortunately so many people who fit boilers are totally ignorant about the finer points of boiler and heating design and setup.

Thats why there are so many boilers so seriously over rated for power.

Boilers are not like car engines ! They reduce their power to a minimum of a third. A third of 18 kW is just 6 kW which is the power a larger house needs on a cooler day.

A 30 kW boiler reduces to about 10 kW and being nearly twice the 6 kW means the boiler needs to turn off. Every time it turns off it enters a built in anti cycling delay!

Thats why over rating boilers is so stupid and yet builders particularly and at least half of boiler installers do this because they dont understand boiler sizing.

About two thirds of boiler installers dont even know about setting the output power in the d0 parameter! A few more know about it but dont bother to set it.

Tony Glazier