Vaillant question

[Mickeyfin]

Hi. I'm looking for some advice on setting up my Vaillant system. I have an Ecotec Plus 618 boiler, controlled by a VRC 630 panel. There are 3 circuits -the hot water, the underfloor heating (which is a mixer circuit), and the upstairs radiators (which is a direct circuit).

My problem is that whenever the hot water is on, the radiators don't work - even if the cylinder's up to temperature. The underfloor (mixing circuit) works fine in tandem with the hot water, but never the rads (direct circuit).

I have 'parallel charging' enabled, which should allow heating circuits to operate at the same time as the hot water.

Can anyone shed any light please? V grateful for any help.

 

[Agile]

Sounds like the HW is robbing all the flow.

There should be a balancing gate valve in series with the heating coil. Close and open this just one turn.

Tony

 

[ALEC1]

wow quite a set up!

what does it say on the 630...does it say the radiator circuit is active?

 

[Mickeyfin]

Thanks for the swift replies.

Yes, the controller says the Radiator circuit is active, but the pump stays off. If you switch off the hot water, the radiator pump starts within a minute, and the rads heat up.

Can they really be mutually exclusive? Seems a bit dumb for such a clever system.

 

[Agile]

So you have a seperate pump for HW and the CH then ? That would not be normal as your boiler has its own pump inside!

Do you have motor valves as well? Do they open?

Sounds like a control problem or a design problem.

Most controller makers expect you to want hot water priority. This could sometimes be turned off.

I seem to very vaguely remember a problem like that and came to the conclusion that the channels were wrongly assigned to the hardware.

 

[Mickeyfin]

It's a high-tech system. We did a self-build project, using a German firm. It might be over-engineered.

 

[ALEC1]

Why would it be over engineered? This is the way they install systems in Germany and vaillant design them...and some of us do in the UK..there are great benefits to doing things the way the design engineers expect... comfort efficiency and reliability...

although I would not have used the 630 controller, but the standard 470 or 430 which caters for two zones and hot water.

if the controller says active, and the pump isn't then you should check that the pump is getting 240v...

 

[ALEC1]

the idea of the hot water priority is to enable the hot water to reheat fast and the heating to be run at a more efficient lower temperature in relation to the heat demand...it saves energy...

not so dumb at all...didn't the installers explain these things to you?

 

[Mickeyfin]

Thanks for all the replies. Yes, I understand why the HW takes priority. But once the cylinder reaches the required temperature, I'd expect the HW to stop heating, and the rads to start.

As things stand, whenever the HW timer is on, the rads are cold, regardless of the cylinder temperature.

 

[ALEC1]

I thought you said that the rads heat up when the cylinder is satisfied???

 

[ALEC1]

ok so the hot water channel has to be off to get heating....

you could take it out of parallel charging as this is only useful if you have blenders on all the circuits except the hot water...

 

[David937]

It's a high-tech system. We did a self-build project, using a German firm. It might be over-engineered.

Call the firm back