Vailant ecotec Plus 438 - slow house heat up - Please help - bucks

[ant2]

We inherited a house with a newish Vailant ecotec Plus 438 boiler.
The heating did always take a while to heat up since living here, since then we have added a few extra radiators and UFH. We have paid various plumbers to improve the system, but if anything it appears worse and takes an absolute age to heat the house and that's with the UFH turned off
I can get radiators individually to get boiling hot, but together they are barely warm after 2.5 hours, I fear in the next few months we are all going to be freezing.

What we have:
15 double rads (11 currently active)
UFH - with 3 bar grundfos pump
4 towel rails
Vailant ecotec plus 438
Grundfos 25/55 pump
4 zones
CH pressurised
Auto by pass
280L HW cyclinder

1.) After much reading I have clocked D0 to 27kw - How do I know if this should be adjusted up or down further
2.) The boiler is constantly cycling on -> pump overrun, this seems inefficient, is this normal? -

3.) We are sometimes suffering from the F23 fault when running UFH, plumber states this is from an airlock and is trying to fix.
4.) A friend bought me a dab- evoplus 80/180m pump, would this help?
5.) Does any one know a "good" heating engineer that can review and improve this system ? - We are based in Buckinghamshire, near high wycombe.
We have had many people review, scratch heads and pay for various "improvements", but we can't find anyone who actually knows what they are doing

 

[dilalio]

@muggles is that way.
Sounds like a LLH would be a good idea on that size system and depends on pipe runs and layout.

 

[fezster]

From experience of the same boiler, that pump will not cut it - it'll barely overcome the internal resistance of the hex at full power, and wont have any head left for the rest of the system. You can reduce d0, but the problem with the 438 is that it fires at a high power output for the first 30/40 seconds, before modulating down. Newer PCB's improved on this somewhat.

When the boiler cycles, what do you see on the front display?

A low loss header (which is what I had installed in the end) is what's required for a multiple zone setup, such as yours.

 

[dilalio]

A low loss header

Sounds like a LLH would be a good idea on that size system

Ahem!

 

[ant2]

From experience of the same boiler, that pump will not cut it - it'll barely overcome the internal resistance of the hex at full power, and wont have any head left for the rest of the system. You can reduce d0, but the problem with the 438 is that it fires at a high power output for the first 30/40 seconds, before modulating down. Newer PCB's improved on this somewhat.

When the boiler cycles, what do you see on the front display?

A low loss header (which is what I had installed in the end) is what's required for a multiple zone setup, such as yours.

Thanks all, fester, i recorded the front display under 2. Or would you like to see something else?
Without going llh, will evoplus 80/180m pump, would this help? Improve things in the meantime?
How much did you pay for a llh system, i presume i could reuse the 2 pumps i have.

 

[Dan Robinson]

We have had many people review, scratch heads and pay for various "improvements", but we can't find anyone who actually knows what they are doing

Problem is, engineers working in a system can only guess at what is hidden in floors and walls. They can adjust tweak and fiddle all they like, but if there is a fundamental issue then they're screwed to a point.

A low loss header might likely be the key, but if there isn't room, closely spaced tees.

As said that system pump isn't enough. But if you do as above it can be kept with a 15-60 or something used for the boiler.

Muggles will know his eggs.

 

[Dan Robinson]

Also try D.0 down to 18.

 

[snb]

Sorted loads of these boilers. Get a low loss header fitted and it will solve it but you will be best to put the 25/80 pump on the output to the rads etc.

As a temporary measure reduce d0 down to 15 or 18 and you should find that it will take longer to get to temp but stop cycling as much.
You maybe able to tweek what setting is best for d0. Find the highest setting that doesn’t cycle.

Also change setting d1 and d2 to 2.

 

[ant2]

Thanks snb. I've made those adjustment.
Ever since new zones were added for the extension, the CH doesn't work unless you isolate all radiators bar 1 or 2.

Also the ufh always causes am f23 error, anywhere between 20minutes to 4 hours of running. Something is clearly not working properly. Best to atleast get it up and running, then looks like I'll need to find someone who can install low loss headers

 

[dilalio]

I'll need to find someone who can install low loss headers

As a said in my first reply @muggles
Look up his profile and you can probably get his number or just pm him

 

[ant2]

As a said in my first reply @muggles
Look up his profile and you can probably get his number or just pm him

He's busy till december, unfortunately i can't wait that long

 

[Dan Robinson]

He's busy till december, unfortunately i can't wait that long

Any Heating engineer who is any good that can get to you at a drop of a hat this time of year without severely inconveniencing either themselves or another customer should be avoided.

 

[Mottie]

He's busy till december, unfortunately i can't wait that long

Consider yourself lucky that he can find the time to post on here.....

 

[dilalio]

Consider yourself lucky that he can find the time to post on here.....

Big difference between dipping in to a forum when you have time for a bit of R&R and sorting out what could be an extensive job!

For instance... I'm posting this now while I am waiting for homeowner who should have been here a 9am... But apparently thought it was OK to pop to the shops after the school run

It's a lot more involved when you're coming off of things that are already in situ, rather than designing and installing a new system.

 

[Dan Robinson]

Can't beat office Mondays . I might even get round to invoicing that accumulator

And shower

And taps

and well.... the whole sodding summer at Well Walk



*sigh*