Vaillant EcoTec Plus 428 range rating

[divedive]

Hi
First post but I have read a bit before doing so.
I've just had a 428 installed to replace an aeging Potterton in an open vent system. I understand the need to range rate the boiler. I have 13 rads and a megaflow for HW in a challet bungalow - reasonably well insulated. Most of the calculators suggest about 20kw for the system, so I think we have the right size boiler but it needs range rating.
We ran the boiler for a week or so at the works setting and did get a bit of anticycling etc. I've now set d.0 to 20 and it seems fine.
My question is - what symptoms will I see if I've set the rating too low ?
Thanks in advance

 

[Agile]

At this time of year you can probably set it at about 14 kW and enjoy better efficiency. Then increase it later as the weather gets colder.

If set seriously too low you may find it takes a while to heat up but while its doing that it will be more efficient.

If set too high it will be likely to heat up too quickly and be unable to maintain the set temperature within the modulation range and cycle completely off for the anti cycle delay period.

Your installer should have set it to something appropriate. Did he complete the Benchmark certificate?

Tony

 

[divedive]

Tony
Thanks - I thought it would be a matter of just taking a little longer to warm up if I had it too low. It seems pretty good on the setting I have now - a nice gradual rise up to the set temp and stays there until the room stat stops calling for heat.
I'm not sure what a benchmark certificate is, but we did discuss the range setting and agreed that as I was comfortable to make the fine tuning, I'd do so.
Its such an easy thing to change I can see how it does when it gets properly cold - its like summer out there at the minute (well a British summer anyway)
Cheers!

 

[Agile]

When a boiler is installed the registered installer has to complete the Benchmark. Its like a car log book.

Without it you may have a problem with any warrantee calls and the installation does not seem to have been notified to Building Control.

Was it an illegal installer ???

 

[divedive]

No - fully legit and he did a nice tidy job.....
I just found what you are talking about - the comissioning checklist (the benchmark bit was hidden under the gas analysis ticket).

 

[Agile]

He should also have notified it to Building Control. Normally through Gas safe who post you a blue Certificate!

Sounds as if you dont have that!

Tony

 

[divedive]

I'm sure its on its way. I'll check anyhow. Thanks for the info.