VRC430, VR61 & VR81 - 2 Zones, both Modulating?

[GeorgeWBush]

Hi,

I received some advice on another thread about heating for my house and I have a follow up question that I hope you can help with.

I would like to setup my house with 2 central heating zones (upstairs and down) using Vaillant VRC430, VR61 and VR81. If we use the VR81 to control the upstairs temperature, would this upstairs zone be using the weather compensator device and be modulating or would this zone be controlled by the zone being turned on-off?

The VR61 manual mentions having the ability to be setup to have 1 controlled and 1 uncontrolled heating zone. Does the controlled zone mean modulating and the uncontrolled mean on/off temperature control?

BTW, will have a unistor cylinder as well, not sure if this is relevant to the above.

Thanks.

 

[ALEC1]

what boiler do you have?

 

[GeorgeWBush]

Will be a vaillant 624 ecotec plus.

 

[ALEC1]

which zone the vr 81 will depend on the way you wire the valves...


why do you want to zone the house? there are simpler ways to save energy....

 

[GeorgeWBush]

which zone the vr 81 will depend on the way you wire the valves...

why do you want to zone the house? there are simpler ways to save energy....

I'm trying to decide between a whole house one weather compensated zone setup using Viessman and 2 weather compensated zones using Vaillant. The biggest advantage 2 Zones I can see is at night, the downstairs could be set very low or even turned off and the upstairs could be set to a night temperature.

What I would like to know is if both zones using Vaillant and the lsited controls would be weather compensated? Or would one of these zones have to be on/off control based?

 

[Norcon]

why do you want to zone the house? there are simpler ways to save energy....

What can be simpler than not heating an area that doesn't need heating?
You remind me off a controls engineer I used to know. Far too often his sales side would kick in.
Though one thing he always did was provide provision to shut off the bedrooms area during the daytime hours. But bedrooms on their own could make no demand on the boiler. Thats how he did/does it.
Anything below 3000sq/ft he isn't interested.
Some homes can have the upstairs heating left off due to their design.
Can your "simple way" beat that?

 

[ALEC1]

given that they don't zone with two port valves in germany, I would avoid any solution using them...

Generally zoning in gemrnay would be a zone of underfloor heating and some radiators, so one zone is mixed, the low trmperature one, and the other one mixed, the direct one. Under this configuration the radiators always have some heat in them,

So to install the vr61 as they would in Germany you would need a mixing valve, which is where costs start escalating...

 

[ALEC1]

No research has ever been done to suggest zoning saves energy in a regularly used house..although in very big houses where some parts are rarely used it may have benefits...

I'd just use TRVS, and if you want to splash the cash I would use rF ones...

 

[Norcon]

given that they don't zone with two port valves in germany, I would avoid any solution using them...

Siemens are German. Are you saying Siemens two ports are not installed in Germany?

 

[ALEC1]

nor are honeywell..they use pumps and headers...mostly..

 

[GeorgeWBush]

So to install the vr61 as they would in Germany you would need a mixing valve, which is where costs start escalating...

Is the cost the mixing valve itself or in the fitting of it? Do you have a link to an example mixer so I can understand the cost involved to be able to make a decision?

 

[Norcon]

nor are honeywell..they use pumps and headers...mostly..

aye and a pump on a header can supply ONE zone. Like the upstairs one.

 

[ALEC1]

I agree..

but there dont seem to be any fit for purpose solutions that just turn on pumps...for this, and I suspect its because in a house <35kws zoning isn't worth it...

if you have two modulating room controls you need a boiler and a mixed circuit, but no hydraulic independence, but with or two mixed circuits and a header for complete independence..

what you saved you would never recouperate the cost of the equipment...

 

[Norcon]

but there dont seem to be any fit for purpose solutions that just turn on pumps

Never heard of a relay?

 

[ALEC1]

with compensation controls....I meant..

the problem is that when a zone calls for heat it needs its own heat input, which may be higher than the zone that may have throttled back... hence two mixers... required to do two zones...