Weather Compensation on Both Rads and UFH?

[mysteryman]

You can separate out different parts of the UFH with the manifold actuators. You should find the Sub mounting kit to be competitive in price after discount.

 

[Onetap]

Evohome has an opentherm bridge that matches the boiler output to the zone demand... the trouble is to use opentherm you need a special widget to convert the OT signal to ebus or KM bus... not generally available in the UK

Or abandon the ebus controls, fit a VR34 0-10V boiler controller and do all the WC, zone control and boiler demand with a controller that provides a 0-10V output.

 

[ALEC1]

well if the house is regularly occupied forget the zoning...just weather comp the whole lot with the viessmann kit including the submounting kit of a brass bodied mixing valve with the mixer motor/actuator

yes a brass bodied mixer with actuator for the floor, and a vitodens 200 boiler will do the job...


you can then zone the floor but the ufh heating manufacturers actuator won't connect with the mixing valve, nor will they need to.

to vary a zones temperature decrease or increase the flow rate through the loops...but a consistent temperature throughout the UFH area will be the most comfortable...

 

[GeorgeWBush]

well if the house is regularly occupied forget the zoning...just weather comp the whole lot with the viessmann kit including the submounting kit of a brass bodied mixing valve with the mixer motor/actuator
to vary a zones temperature decrease or increase the flow rate through the loops...but a consistent temperature throughout the UFH area will be the most comfortable...

Thanks again Alec for your posts, very greatful (and to everyone else too)!

How would I vary the flow through one of the loops, Would this be done via the Vitotronic 200 WC device?

 

[GeorgeWBush]

Spoke to Viessman technical again. I appreciate the following may be old news to those that have posted already but thought it may be of use to others in my situation looking at setup options.

For WC on 1 zone of rads and 1 zone of UFH, and as Alec and Mysteryman have already advised, this is what they said I needed:

*Vitodens 200W System Boiler (latest model is wb2c)
*Sub-Mounting Kit with mixer
*Vitronic 200 HO1B WC Controller
*If you want to wall mount this (up to 5m from boiler) the wall mounting bracket, p/n 7299408
*Viessman hot water sensor (for the unvented cylinder)
*For 3rd party unvented cylinders, you also need a H1 Internal extension module

If you go for the Vitocell 200/300 cylinder, you don't need the H1 internal extension, but still need the hot water sensor.

I also asked about adding room thermostats to the setup and as others have already said, it's not required. If you want to increase/decrease the internal temperature. you simply go to the WC controller and select the appropriate heating curve. Individual curves can be set for each of the 2 zones.

The control is also programmable.

There was a point to note using this setup the guy on the technical line mentioned, for the UFH to be on, the rads need to be on. You can have the rads on and the UFH off. You can not have the UFH on and the rads off. Can't see this being a problem for me.

By the way, I asked what the difference between the 200 and 300 cylinders was. I was told the 200 Cylinders are in fact made by Gledhill and Viessman stick their badge on it. The 300 is made by Viessman.

Thanks again to all that posted. This is a great forum!

 

[Onetap]

Just phoned up Vaillant tech support asking if WC can be set up with rads and UFH and the response was their WC will not work wih UFH because UFH can not be linked to the ebus. "So your WC will only work with radiators?" Response was yes.

That can't be right can it!?

I've just remembered that their WC controllers incorporate a floor drying option. I'd always assumed this was for slowly drying out the screed on an UFH installation.

I find their response a bit of a concern.

 

[Norcon]

There was a point to note using this setup the guy on the technical line mentioned, for the UFH to be on, the rads need to be on. You can have the rads on and the UFH off. You can not have the UFH on and the rads off. Can't see this being a problem for me

Lets say you want your kitchen heated by 6:00pm and theres a two hour delay to reach set point due to the higher inertia.
Easy , so you start the ufh at 4:00pm. So the rads run for that period also which might only have a 30 minute delay to reach set point.

Are you happy that they are running 90 minutes unnecessarily?

 

[mysteryman]

They will only be running at underfloor temperature during that time. You can add a relay box and a 2 port valve to stop it happening, but this may nor be worthwhile.

 

[ALEC1]

its not unnecesary heat for those 90 minutes...people forget if it is colder outside than in their is a heat loss..in the case of a correctly set up viessman with weather comp the night set back temperature should be 6-7c below normal room temp, so both circuits will be active but at lower temperatures than room temp. In reality the floor ramps up to around 35c, and the rads will be at that temp more or less..


There is nothing to suggest that this is wasteful of energy, just more comfortable....

 

[Norcon]

Pulling on a woolly jumper is comfortable too and no energy wasted.


Used to work along with a highly strung controls engineer and it bugged him no end when I told him I always found the off button to be the most energy efficient.

 

[ALEC1]

well it is! but people have heating to be warm...the key is to use energy wisely.....

 

[Norcon]

Here's some of his work. I was there to copy and fill me boots on the plumbing layout as I was doing something similar in another large gaffe. Perhaps not the tidiest.
This ones about 7000sq/ft of ufh. RVP 330. Three runs of uponor econoflex into the property 30m away. Plumbers made a slight boob there.
Good job the client didn't mind and shovelled the cash as and when needed.
Do you design and build your own panels?

 

[ALEC1]

the controllers come with the boiler and cost about £200, take 30 second to instal, and a bit more to set up......

 

[GeorgeWBush]

Just phoned up Vaillant tech support asking if WC can be set up with rads and UFH and the response was their WC will not work wih UFH because UFH can not be linked to the ebus. "So your WC will only work with radiators?" Response was yes.

That can't be right can it!?

I've just remembered that their WC controllers incorporate a floor drying option. I'd always assumed this was for slowly drying out the screed on an UFH installation.

I find their response a bit of a concern.

My unerstanding now is it's pot luck as to the technical understanding of the person on the end of the phone you get when calling Vaillant tech support. I'll be trying them again next week.

 

[GeorgeWBush]

There was a point to note using this setup the guy on the technical line mentioned, for the UFH to be on, the rads need to be on. You can have the rads on and the UFH off. You can not have the UFH on and the rads off. Can't see this being a problem for me

Lets say you want your kitchen heated by 6:00pm and theres a two hour delay to reach set point due to the higher inertia.
Easy , so you start the ufh at 4:00pm. So the rads run for that period also which might only have a 30 minute delay to reach set point.

Are you happy that they are running 90 minutes unnecessarily?

Thanks for highlighting this scenario... I'm not happy with it no. I'm glad i found this out before purchasing.