Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensator

[amithc]

Hi All,
I hope someone can help me, I am not a plumber, but a home owner, the process of trying to get accurate advice seems tricky, and both Vaillant and Heatrae Sandia seem to have no helpline after 4pm on a saturday.

Background:

We are nearing the end of a building project which has also had an upgrade to the heating system.
After the heating engineer installed the Megaflow unvented cylinder and the Vaillant Ecotec system 630 boiler I was able to get heating and hot water.
As it was not fully wired, we just put a simple on/off timer to turn the whole boiler on and off a couple of times a day.
That was fine during the summer, as it gave us hot water, and we didn't really need heating, though we tested it and it was working.

Now the tricky part.

No hot water:

The electricians have now connected the boiler (Ecotec System boiler 630) to a VR61 Wiring Centre,and I use the VRC470f to control it.
The VRC470f correctly shows me the outside temperature and seems to control the heating correctly.

However, in terms of hot water, nothing is working. When I look at the boiler itself, at the bottom of the control panel display there is a symbol on the right to indicate there is a heating connection, but on the left there is nothing at all for the hot water.

The only way I can get hot water is to turn on the immersion.

So my assumption is that in adding the VR61 something has been broken, disconnected or just wrongly wired.
Is there anyway for me to get diagnostics or to work out what has gone wrong ? Is the VR61 the right wiring box ?
Or is this combination of boiler, cylinder and controls just not going to work ?

Wiring Centre to Megaflo:

If I understand correctly, to make the most of the boiler, I need to feed back the cylinder temperature to the boiler, by connecting the VR61 to the megaflo using a VR10 sensor. As the Megaflo doesn't have a dry pocket, it seems it can be used as a "Contact Sensor" by strapping it to a suitable pipe.
Is this correct, or is there some other sensor I should use ?

I really appreciate any advice or assistance.
Thanks in Advance.
AC

 

[Kev the gas]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

My neighbour has a similar set up.

Their Ariston cylinder split under warranty, I found the sensor pushed into the low level dry pocket and the Ariston thermostat removed.
I was concerned to do it this way as there is no over heat stat facility, I spoke with Vailiant who were happy for this to be
done, and said just rely on the boiler overheat stat !

Remove the stats from the Megaflo and insert the stat into the cylinder.

Personally I dont like it like this but was given the thumbs up from Vailiant.

I would be happy to install Vailiants but find their control systems confusing to explain to customers.

 

[amithc]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

My neighbour has a similar set up.

Remove the stats from the Megaflo and insert the stat into the cylinder.
.

Thanks for your quick response, but I have to ask the most basic of questions, when you say remove the "stats" from the Megaflo, I am not sure what you mean ?
DO you mean remove the immersion heater and it's thermostat ?

TIA

 

[Kev the gas]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

The hot water cylinder stat, I believe in the Megaflo it is a combined over heat stat as well.

 

[amithc]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

What I don't understand is why the boiler has no symbol for hot water in the bottom left of the display on the boiler, does this indicate a wiring problem ?

 

[chris watkins]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

Hi amithc, can I ask why you are not asking the engineer who installed the boiler & cylinder to come & sort it out, I assume you have paid good money for this installation so why are they not sorting it out ? Who selected the boiler & cylinder they are both to good bits of kit but how they are to be linked together should have been sorted out beforehand shouldn't they ??

I am with Kev on the High Limit stat I would always like to see one & I am not so sure you can rely on Vaillant's word on things they manufacture the boiler only the Part G registered engineer who installs the Megaflo needs to be the one who decides if it is OK or not they are the one who has to sign it off.

 

[amithc]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

Hi amithc, can I ask why you are not asking the engineer who installed the boiler & cylinder to come & sort it out, I assume you have paid good money for this installation so why are they not sorting it out ? Who selected the boiler & cylinder they are both to good bits of kit but how they are to be linked together should have been sorted out beforehand shouldn't they ??

I am with Kev on the High Limit stat I would always like to see one & I am not so sure you can rely on Vaillant's word on things they manufacture the boiler only the Part G registered engineer who installs the Megaflo needs to be the one who decides if it is OK or not they are the one who has to sign it off.

I am trying to get hold of the original installer, but am having some difficulty reaching him, as they were subcontracted by a building contractor. It seems the lesson to be learned here was to insist on my own heating engineers.
I am also trying to get to speak to Vaillant and Heatrae Sadia, but it hard to get through at the best of times,and no one available on a sunday.
Although the original installer told me it would all work together, it would seem it doesn't, so i was hoping for some help from this community that someone else might have done the same thing before.
I very much appreciate any advice.

 

[chris watkins]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

Switch the immersion on & get hold of the main contractor tomorrow first thing & get him to sort it out. There are too many safety issues involved here & add to that if you start messing around with anything it will lead to contractual problems & they could ague that you caused the problems.
As an example -
Megaflo will not be interested as there product is being altered & so is no longer covered by the BBA approval / testing.

The problems are likely to be electrical but what are you going to start doing re-wireing on a Sunday afternoon ??????

 

[amithc]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

Hi Chris,

Thanks for your reply.
The problem is that there seems to be a lack of information available.
I don't plan to do any re-wiring, but I do want to be in a position, where when the original installer comes back, if he says,
a) it can't work , you need to have a Unistor cylinder from Vaillant
or b) I can do it, but i need to alter the megaflo
or c) you need to use a separate controller for the hot water
that I know whether anyone has done it before, or whether he is talking out of his hat.

Sounds like if the Megaflo has no way to connect (whilst remaining under warranty, and still remaining compliant and safe) that I need a different cylinder.

 

[chris watkins]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

No I didn't say that the Megaflo was not suitable, only that the competent person who is installing it & signing it off need to satisfy themselves that it is installed to Part G of the Building Regs.
Most things in this world can be made to work (even my wife) given time & money, so give the people you are paying your money to A little more time to sort it out & I feel sure the results will be worth both.
Good Luck.
CW

 

[Megaflo-Experts]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

I had a similar problem with a Worcester Bosch boiler, with the integral diverter valve. This enabled the boiler to switch between hot water and heating, and the issue was the Worcester needed to use it's own cylinder stat instead of the one in the Megaflo. Worcester had a technical bulletin which advised to alter the thermostat wiring and bypass the supplied 2 port valve...something Heatrae Sadia were not happy with!
Ultimately, you need to speak to Vaillant and see if they have a solution.
Good luck!

 

[amithc]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

I had a similar problem with a Worcester Bosch boiler, with the integral diverter valve. This enabled the boiler to switch between hot water and heating, and the issue was the Worcester needed to use it's own cylinder stat instead of the one in the Megaflo. Worcester had a technical bulletin which advised to alter the thermostat wiring and bypass the supplied 2 port valve...something Heatrae Sadia were not happy with!
Ultimately, you need to speak to Vaillant and see if they have a solution.
Good luck!

thanks for your help. I will update the thread once i get through to Vaillant.

 

[Howsie]

Call a plumber out. You may end up causing more damage than will cost to put it right.

 

[amithc]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

No intention of touching it, just want vaillant or megaflo to tell me it can be done and how to do it so i can be in the know when talking to the plumber. My big worry is that they will both say, that to connect them would invalidate warranty somehow.

Cheers

 

[Howsie]

Of course it can be done. Any decent plumber will know how to do this.

 

[amithc]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

Of course it can be done. Any decent plumber will know how to do this.

that's reassuring. Now to find a decent plumber ;-)

 

[Howsie]

Lol. Post up your location and someone will drop you a pm.

 

[amithc]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

I am in west london.

 

[Howsie]

How far west? Heathrow?

 

[amithc]

Re: Vaillant Ecotec System, MegaFlo 250L, Vaillant VRC 470f Wireless Weather Compensa

ealing, w5.