Automated radiator valves

[paulca]

You have series connection? If you system even able to have radiators closed?

Not exactly, but it's not parallel either, that would involve huge amounts of plumbing.  One radiator is series, the "feed" radiator, usually the bathroom.  The rest are parallel to the heating loop.  But, the circuit will go through/past each radiator in turn, although I believe my current system has two parallel circuits, one downstairs, one upstairs.  Each radiator will take heat out of the water and that water will merge back into the loop cooling it.  It's simple physics.  If you have X amount of heat in the water and a radiator puts out Y heat the heat remaining in the water is X-Y.

However, if you do a bit of research into how to size radiators you will find it matters where in the house, or more importantly, where in the circuit the radiator is.  A 1 meter single radiator first in the circuit might put out <n> Kw, but the same size of radiator much further along the circuit will put out maybe 1/2<n> Kw.  So radiators in more distant rooms have increased size.  A 2Kw radiator early in the loop might be a 1 meter, single, standard height, but much further in the loop a 2Kw radiator needs to be a 2 meter double radiator to produce the same output.

[nctnico]

How big is you house? To me it sounds it is worthwhile to rip all the old heating out and install new because what you now have sounds like a big mess anyway. This time using individual tubes to each radiator. And by tubes I mean semi-flexible plastic tubes which are intended to connect radiators to a central distribution unit. In my home I have two of these distribution units (hubs) which then feed the radiators. This is relatively quick and easy to install because it doesn't involve working with steel tubes.

[langwadt]

...

if you lower the water temperature won't the valve just open more?

The valve will open longer. If your house is sufficiently insulated the frequency of temperature instability will be lower, and you will be closer to the requested temperature. More comfort.
If you're pumping 60C water through the radiators every 30 minutes it will be degrees over, then degrees under the requested temperature. When the same temperature can be maintained by pumping say 40C for a while as well. For gas heaters, this is cheaper.

I'm quite sure it regulates flow rate, it would be easy to hear if they were cycling on and off and they are not

I have district heating it's 60-80'C depending on season

[paulca]

How big is you house? To me it sounds it is worthwhile to rip all the old heating out and install new because what you now have sounds like a big mess anyway. This time using individual tubes to each radiator. And by tubes I mean semi-flexible plastic tubes which are intended to connect radiators to a central distribution unit. In my home I have two of these distribution units (hubs) which then feed the radiators. This is relatively quick and easy to install because it doesn't involve working with steel tubes.

Seriously, nobody here does that.  They all operate on a loop.  It' s not a mess, it's the standard applied here for the past (at least) 60 years!  I currently have 8 radiators on two floors with 2 potentially being added in the garage later.  Your idea would require a send and return to each radiator which is 16 quite long pipes and all the lifting of floors, drilling beams, tracking up walls etc.  Would cost thousands!  That's before the distribution hub or whatever.  I think any local plumber would look at me like I'd gone funny in the head!

In other threads I have found there is a massive difference between how different localities have different heating systems.

[Jeroen3]

It makes no sense to run the pipes in star topology. Even in the Netherlands I have never seen that.

[nctnico]

It makes no sense to run the pipes in star topology. Even in the Netherlands I have never seen that.

Then you should open your eyes. It is done that way in homes for at least 25 years. The reason is simple: the plastic tubes are simple to install in a cement floor and are easy to fit onto a radiator. The gain is in being able to install the system quickly and the tubes are quite cheap as well. Because the tubes run end to end (inside a sleeve) there is no chance of leakages in couplings at places which are difficult to access. With a bit of luck it is possible to pull a tube out and replace it (if you drill a hole through it by accident).

@Paul: if you have only 8 radiators then installing a star system with a few hubs placed at strategic places is doable. In your case that will land you with single spots from where you can control each radiator very easely. You were already planning on running mains to each radiator so what is the difference between running new tubes or running mains wiring? Ofcourse I'd assume I'd install it myself so cost of labour is not so much of an issue to me. My own home had 10 radiators originally but I replaced a couple of them with floor heating.

Maybe it is worthwhile for you to watch some Youtube videos on how they install new heating systems and which materials they use. You'll likely see some interesting ideas and techniques.

[paulca]

Well basically in order to change from I believe what is called a one-pipe system to a two-pipe system (plumbers suck at naming things btw), it would be akin to a complete 'rewire'.  Not only would this involve, well, moving out as all the floors upstairs and downstairs would need to come up, but it would involve tracking large recesses up through the block walls, replastering those after the pipes and installed and fitting these distribution valves, powering them, running control cables and buying hundreds of feet of plastic piping.  Not something I would be prepared to do myself.  Not least as there are standards and building regulations to adhere to.  The reason you care about building stanards and regulations is because if you want to sell your house it's important, but more importantly for your building and contents insurance, it's important.

So I am swapping the heating system from oil fired to gas fired and replumbing the storage tank system to an on demand system.  This will reuse the existing copper piping. The cost is around £2700.  A complete re-plumb with all plastic piping and two-pipe parallel radiators would, most likely, cost me 2 or 3 times that for a professional installer to do it and I would, most likely need to spend a week in a hotel, costing another £1000.  Of course if I was going to do that, I would get the 1970s electrics rewired at the same time, to do otherwise would be silly.  So add another 2 or 3 grand.  Suddenly it becomes a complete renovation and while that may increase the valve of my house by 10 or 15 thousand, it will cost me something similar and take a few weeks where I would probably need to move out.

As to running mains to the radiators.  First I don't need/want to control them all and second the mains is already distributed around the house with plug sockets existing close to the radiators in question anyway, so all I really need to do is run a few feet of white, flat, two core along (or behind) the skirting board to the radiators.  Hide the remote relays below the radiators and job is done.