Central heating zones

[ChasingSquirrels]

I have always thought central heating zones looked fab, but you would need to get the house re lumber to create the zones and that would be mad ... I have just seen a wireless system where you have a central controller and each radiator has an electronic controlled valve, so you can set the zones like that.

Looks great, but a couple of questions - if PigletJohn or anyone else technical is around that would be great.

Do you have to put the controllers on every radiator or can you leave some without them - I am assuming if certain radiators just kept the existing TRVs then whenever the heating was on for any of the zones then the un-zoned radiators would come on at whatever their individual TRV was set at (so spare bedroom on the dechill setting, downstairs loo on low/medium as so small and doesn't need much to heat but nice to keep warm, hall on medium as I like it warm there). Is that right?

Are the radiator controllers much bigger/unsightly than normal TRVs?

Anyone got these and able to comment on them?

Finally, my lounge is around 12f x 17f with 2 x tall (I think 180cm) narrow radiators either side of a patio door in the corners of one of the 12f walls. Next to each radiator along the long walls is a 1m x 1m x 50cm bookcase - not touching, probably 30cm between rad and bookcase, so bottom half of radiator isn't really exposed to the room but top half is. The TRVs on these rads are on the inside of the room (rather than right in the corner of the room) but this places them v near to the patio door curtain.
There isn't a separate thermostat in the house, so the temp controllers are just on these rads.
Does having the thermostat placed in this way enable a realistic reading of the overall temp in the room - I am presuming not?
If it doesn't, does this really matter as presumably I just set the temperature higher than it would need to be if it was being measured on, say, the opposite wall to ensure that the ambient room temperature is reasonable?

You say you have no room stat.

Fix that as a priority, preferably a programmable stat.

Afterwards, if you have money to burn, you can get ekectronic radiator valves.

Thanks - why do I need a room stat?
I am rarely warm enough in the winter and rarely turn the rads in the lounge down. If i had a room stat it would be in the lounge and i would have the temp at whatever it needed to be to keep the heating on - what is the point of that?

I can see that the zoned thing would be money to burn category.
But the alternative is either heating areas i don't want heating, or going round adjusting individual rads half an hour or whatever before i want to go in to a room - which I don't do. And switching lounge rads down at night and bedroom rads up so they come on in the morning, then doing the reverse before we leave the house in the morning.
I don't do it now and i am unlikely to change - but
the zoned areas would do it for me.
I think I had decided against it though as the payback period would be too long.

You say you are rarely warm enough in the winter. Thsi is most often because the radiators are not big enough for the heat loss of their rooms. Often radiator size calculations are rather optimistic, this keeps the price down which many customers find attractive when looking at quotes.

Feel your radiators first to see if they are hot enough. Assuming you do not have pipe thermometers, the Flow pipe should be "too hot to hold" (about 60C) and the return pipe should be "too hot to hold for long." (about 50C or less) This is assuming you have a modern condensing boiler with the boiler temperature set to about 60C, which is its most efficient operating temperature. If so, and the radiators are properly hot but are not heating the room sufficiently, then their output is too low, basically because they are too small. Or, in the case of narrow high radiators, they are particularly good at heating the ceiling. Modern boilers are generally more than powerful enough for an ordinary sized house, especially if they are combis, which have to be very powerful to run a hot bath, so lack of heating power is almost due to undersized radiators.

Older iron boilers usually run at higher temperatures as they have no condensing efficiency.

Larger radiators are also capable of heating a room faster than small ones. it sounds like you want to heat certain rooms for certain periods, then not. If you actually want to turn the heat on and off in those rooms, you will need larger radiators to heat them quickly. I have oversized radiators to do this, and mine are about twice the minimum calculated size, and take at least half an hour to warm a room from cold, or an hour to make it comfortable with warm walls.

Thanks.

I don't think the problem is the heating, I think the problem is that I feel the cold a lot!

The in/out flow pipes on the radiators are as you describe, the rooms heat up pretty quickly, other people in the house are warm enough - but I am snuggled under a duvet with my big wooly cardi on!

As you say, I would like to heat certain areas at certain times, and others at other times, and I would like that to be automatic rather than rely on me setting the valves all the time.
But it seems the cost of installing a zoned system would be such that the heating costs saved would take a long time to cover the installation cost.

I still don't understand why I would need a room stat?

Re programmable - the boiler has a programmable timer with 3 on/off cycles a day which can be different for each day of the week.
It is a combi boiler, so the timer is just for the heating, the hot water is always on (although I have seen postings about an economy button which turns off the always on function - but haven't seen such a button on mine).

What I do need is to get the bloody hot water override valve fixed and for it to stay fixed. As that seems to be an impossible request I will have to make do with turning the heating off when someone has a shower!