Vaillant System with 2 heating zones and hot water

[virgilns]

We've used the heatmiser kit on a few projects now both the 230v and 12v. We use emmetti actuators on pegler trv be aware not all actuators have enough travel to work a trv valve.
I've gone room by room because the back of my house gets the sun most of the day. The back rooms can get toasty without heating but the front is still freezing. I can also set different time temperature settings for each room as required.
Btw heatmiser make the jg controls. They are identical except price, oh and the fact that heatmiser actually know how they work if you need some support.

Now they look like nice little actuators! Might get one for a play...only a tennr!

Sorry what i meant by "why go room by room" was really, why go for seperate program control rather than for a thermostat per room with actuators creating individual zones, but with the heatmiser central control unit...can do 8 zones if i remember rightly?

And does the solution work well? The actuators are either on or off as oposed to a normal trv wbich opens/closes slowly...do you get a lot of overshoot on the temperature ramp up ?

 

[virgilns]

the vaillant controls described need no other. and installing the way the vaillant design engineers dreamed up will give you a seamless and decent heating system, although you will have to get used to low temperature circulation in the radiators if only the UFH is on..unless you have a LLH

The issue there though is that its still in ine zone..so still heating more of the house than neded...unless youre saying you can have multiple zones with vaillant kit? The vrc630 does that but its 700quid...

 

[RickMoore]

Now they look like nice little actuators! Might get one for a play...only a tennr!

Sorry what i meant by "why go room by room" was really, why go for seperate program control rather than for a thermostat per room with actuators creating individual zones, but with the heatmiser central control unit...can do 8 zones if i remember rightly?

And does the solution work well? The actuators are either on or off as oposed to a normal trv wbich opens/closes slowly...do you get a lot of overshoot on the temperature ramp up ?

For one, using seprate programmable stats allows different set back temps, and time control for each room. e.g our bedroom is a little cooler than the kids overnight, and downstairs rooms are heated for longer than the bedrooms during the day, kids bedrooms heat up earlier than ours etc.
For two, with the price differance between programables and normal room stats, and a 4ch programmer it worked out cheaper

Yes 8 zones on the wiring centres, I have two wiring centres, one to handle the 6 rads, and one to handle the 2 UFH zones and Hot Water. There is also a 4 zone version on the 230v controls.

It works very well, the stats are pretty accurate and I've not noticed any over shoot, each room is comfortable. We've installed a few of these systems now and customer feed back has been very good.
System design is important though, you need to remember the boiler may fire to heat just one rad or UFH zone, on the other hand it may need to heat the whole house when it's -18 outside. Either a boiler with a great enough modulation range to cope with that, or a low loss header will be needed for it to work best.

 

[virgilns]

Now they look like nice little actuators! Might get one for a play...only a tennr!

Sorry what i meant by "why go room by room" was really, why go for seperate program control rather than for a thermostat per room with actuators creating individual zones, but with the heatmiser central control unit...can do 8 zones if i remember rightly?

And does the solution work well? The actuators are either on or off as oposed to a normal trv wbich opens/closes slowly...do you get a lot of overshoot on the temperature ramp up ?

For one, using seprate programmable stats allows different set back temps, and time control for each room. e.g our bedroom is a little cooler than the kids overnight, and downstairs rooms are heated for longer than the bedrooms during the day, kids bedrooms heat up earlier than ours etc.
For two, with the price differance between programables and normal room stats, and a 4ch programmer it worked out cheaper

Yes 8 zones on the wiring centres, I have two wiring centres, one to handle the 6 rads, and one to handle the 2 UFH zones and Hot Water. There is also a 4 zone version on the 230v controls.

It works very well, the stats are pretty accurate and I've not noticed any over shoot, each room is comfortable. We've installed a few of these systems now and customer feed back has been very good.
System design is important though, you need to remember the boiler may fire to heat just one rad or UFH zone, on the other hand it may need to heat the whole house when it's -18 outside. Either a boiler with a great enough modulation range to cope with that, or a low loss header will be needed for it to work best.

thanks Rick, very useful.

Your reasoning is exactly the same as why i want to do mine in a similar way. Just like the idea of the heatmiser central control panel touch pad which can also set seperate times and temps for each zone/room (as I understand it).

Do you think this with a vaillant 638 and weather control would work well together to provide the modulation?

Also I need to get the towel rails on a separate zone so they can be on in the summer...so i'm thinking a pipestat on the return for them rather than a room stat...does that make sense? and presume the controls still be laid out the same way...actuator on the rad?

what i really want is little thimble stats for the rooms linked to the central controller...know any way of doing that or does it have to be a fully functional adjustable stat?

 

[ALEC1]

weather comp follows its own logic, according to programmed values. The problem with your proposal is that there is no feedback to the boiler for a higher than calculated demand for a particular zone.

In other words the calculated flow temp may not be high enough when a zone calls for heat, and you may end up frustrated!

For the average UK house zoning is just an expensive way of complicating things, as said the hydraulic layout becomes more involved than it need be, and more expensive to install.

Weather comp is a low cost solution to enhance fuel efficiency...forget expensive zonng!

 

[RickMoore]

thanks Rick, very useful.

Your reasoning is exactly the same as why i want to do mine in a similar way. Just like the idea of the heatmiser central control panel touch pad which can also set seperate times and temps for each zone/room (as I understand it).

Do you think this with a vaillant 638 and weather control would work well together to provide the modulation?

Also I need to get the towel rails on a separate zone so they can be on in the summer...so i'm thinking a pipestat on the return for them rather than a room stat...does that make sense? and presume the controls still be laid out the same way...actuator on the rad?

what i really want is little thimble stats for the rooms linked to the central controller...know any way of doing that or does it have to be a fully functional adjustable stat?

The EcoTec 637 will modulate down to a minimum of 12kw, which is going to be way over the loss for any one room. No matter what the boiler won't be able to modulate down anywhere near enough than needs to be possible. Are you sure you need such a large system boiler ? If so then a low loss header is probably the way forward.
Vaillant have told us that their controls won't and can't be made to work with other controls. If anyone can tell me different I'm all ears.

If the towel rail isn't the only heat source in the bathroom(s) we usually run them as a second hot water circuit on a timer, and have them on a zone zalve, rather than an actuator. I don't know of any IP66 actuators that would allow you to use it in a bathroom. If there were it won't look all that good compared to nice shiny towel rail valves.

Do you mean their dial thermostats ?, that will give you time/temperature control of up to 4 zones. Within each zone each rad/ufh would have independent temperature control.

 

[ALEC1]

well vaillant aren't quite telling the truth... in europe you can buy a widget that converts Opentherm to Ebus, so Opentherm controls can work with vaillant. All boilers sold in the Netherlands have to be Opentherm compatible, which is why the widget is available.

I think thats a good point a small zone say one room with a heat loss of 3kws (which is actually a large room) is too small for most boilers to handle well...even with a header the boiler will cycle excessively..

In bathrooms I usually put the towel rads on an electric element with integrated temperature control and a timer and the radiator circuit..

 

[RickMoore]

Thanks Alec, that's something to look into. Alot of our systems though are also tied into control4 though, so it gives us the problem of the controls having to work with both.
Heatmiser do a boiler sequencer with WC in their commercial controls range. I'm waiting on some info back from them on it, as to how it works. Got to design a twin 618 system with WC and zoned by room, and has to work with control4
I sometimes extended the anti cycle time on the boiler to help with the short cycling problem when only 1 room calls for heat. But that only compensates so much. Getting the system balance right and the right ssize boiler are also very important.

 

[ALEC1]

Zoning implies a rapid heat up time by definition, weather comp seeks to run the boiler at the lowest possible temperature, so the two together are not a happy mix.

 

[RickMoore]

In some cases I completely agree. Though not all the time. We do a lot for disabled clients where some rooms are designed to hold 24c 24/7 while other rooms are somewhat cooler. Wc ought to help this happen more efficiently.

 

[ALEC1]

It does if you run the system 24/7..


german boiler controls are designed around "stable state' conditions, hence their excellent performance around that.

turning things on and off is a peculiar british obsession, which conflicts with that...

the two arent really compatible as people are finding out... zonal control is an easy sell, its what the client understands, but it is not in their best interest to install it...for the reasons discussed.

 

[RickMoore]

Zonal control to give different time temperature control with WC is looking good on paper. On/off zonal control with WC just wouldn't work I agree. There isn't a one size fits all way of doing things and what's in one clients best interest won't be another's. So in the right circumstances wc and zonal control should be completely compatible.

 

[virgilns]

Very interesting conversation!

So my desire to zone the house comes not from differing heat loss charactoristics in the building fabric, but the desire to only heat bits of the house in use at any one time...id like to be able to set he living room on during the day and off in the evening and the dining room (it will be an adult only lounge free of toys and other assorted kids rubbish) on in the evening bit off in the day when its never used...same for bedrooms...

a great example i heard was the equivalent of a light switch...you don't have every lightbukb in the house on one dimmer switch in the hallway, but do want dimmrs on individual rooms, so i can turn on and off the lights at will and each to their own brightness

I love an analogy!

I do see what you are saying though regarding the weather comp setting the max limit for the potential heat provided though...but surely that's no different than a trv on a fad...the roo.stat and actuator are just providing the equivalent on the trv, but electically operable and rogrammable......or am I really missing the point here?

 

[virgilns]

.

If the towel rail isn't the only heat source in the bathroom(s) we usually run them as a second hot water circuit on a timer, and have them on a zone zalve, rather than an actuator. I don't know of any IP66 actuators that would allow you to use it in a bathroom. If there were it won't look all that good compared to nice shiny towel rail valves.

Do you mean their dial thermostats ?, that will give you time/temperature control of up to 4 zones. Within each zone each rad/ufh would have independent temperature control.

Aren't the network controllers deemed ok for bathrooms as only 24 volt...need to check...

Really mean rather than having a box on the wall to change the temp or even the program for the room, just a thimble sensor wired back to a controller elsewhere...seen them on the Honeywell evohome set ups and make s really nice non intrusive set up (though it does mean that you have no override in the room itself, rather back at the main controller)

I'll have a Google and see what's available...

 

[ALEC1]

If a room is used regularly there probably is no efficiency gain in turning the temp down as you would use as much to heat it up as you would to maintain the temp.

The key is what is regular???

Then again there is the issue of heat loss which will determine the power required to bring up to temperature....

As is always said reducing heat loss is the path to comfort...