Modernising room heatng controls - what's available?

[nospam]

The other "boiler replacement" thread has produced some useful ideas (thanks to all!) so I've started this new thread just for room heating controls. I plan to divide the new house into multiple zones, each with their own timer/stat, and would value hearing the team's experiences, comments and suggestions on the following stream of consciousness.

If zoning is taken to the limit, then each major room would be a unique zone and then it would be possible to detect that a window was open and to (optionally) switch off the heating in that room. The window detection could double as input to an alarm. This leads to the concept of a heating loop with rooms or radiators tapping-off heat according to demand, with a loop flow switch to detect when there was no demand. Ideally each rad or room would be piped back to a central manifold, with indiviual valves, but this isn't practical without major disruption If it's not possible to isolate a room without major disruption, or for minor rooms, then motorised rad valves (or, as a last resort, TRVs) could be used. To avoid a lot of unsightly wiring the window sensors would need to be wireless (lots of windows so price is an issue too). Some immediate questions from that are: how to detect lack of heat demand on the primary heating loop, sources of window switches.

Another thought is whether it's worthwhile compensating the room stats for external temperatures, and if this possible for multiple stats.

[Bob Minchin]

Another thing you might want to consider is individually controlled rad valves. These have a motor drive head that fits onto existing thermostatic valves. They are wireless controlled and with as many wireless temp sensors as you want to fit you can have a different time and temperature profile in every room. Motor heads are battery powered so no visible wiring. One I looked at a while back had PC software to configure the system then download to a controller box that in turn talked to the valves. No need to run the PC unless you want to monitor/change they system.

Weather compensation does not normally interact with the room stats but modulates the boiler power output assuming your boiler is capable of that. Mine is not designed for weather compensation but I am experimenting with an Arduino to adjust flow temperature based on outside temps.

[Capitol]

I really appreciate my low tech unzoned heating system. A few rad thermostats and a nice guesswork electronic hall stat works with no need to interfere with anything whatsoever.

[nospam]

:-) I guess it depends on the size of the house. I changed my current house to have 3 zones (up, down and towel rads) but that was very simple to do during a major re-furb - 4 S-plan valves and two timer/stats - plus it also gets rid of the awful Y-plan valve. It cost very little and seems to have been worthwhile. FWIW I also made a DHW loop so get nearly instant hot water at all taps (some of them are quite a way from the DHW tank) and that was worthwile too. The only cost for that was a recirc pump, a pipestate, a bit of pipework and a loss of stratification in the megaflo. The new house is a reasonable size and I need to think carefully about how best to update the heating and insulation because it's likely to be my penultimate resting place.

[Bill Taylor]

I have used the eQ-3 MAX! retrofit system to replace most of my TRVs; doing a wired system would have been too disruptive.

It seems to be the cheapest such system around, it's versatile and works well. The valve actuators aren't very elegant and can be quite noisy in operation, but I can put up with that for the cost saving.

You can just use individual programmable actuators; if you have more than 1 radiator in a room control the actuators as one with a wall thermostat, or add a Cube which links all the units together and lets you set everything from one web page - much easier than programming the valves/thermostats individually. Window sensors are available to shut the heating down if a window is opened.

The actuators have some degree of proportional control, but weather compensation should be done by controlling water temperature to be worthwhile.

As the system is quite popular in Europe a few people have written interface programs to get data from the cube. I use this

which lets me scrape room temperatures for use in the HA system, but it can do more than that.

[Bob Minchin]

AIUI when doing any degree of refurbishment to domestic heating use of zones is mandated bu building regs although you can still programme them each zone do the same.

[nospam]

Interesting, although some obvious things to check are battery life, whether one stat can control more than one rad valve. Do you recall what the system was called?

Yes, thanks for that. I was confused because it was an option on the Honeywell timer/stats I installed here, but I think that just allows the set temperature to be adjusted as the outside temperature changes, rather than modulating the boiler temp, which is clearly better. So much to learn and so little time :-)

[Capitol]

You tell someone??

[PeterC]

Yes, KISS! I've balanced the system, have TRVs in akk but 2 rooms and then tune the heating (by a limited amount) with a lockshield valve in the room with the 'stat. In not too cold weather I open the LSV to get this room warm and in cold weather turn it down to about a third of a turn open. Minor tweaks to some TRVs a couple of times a year and it works as I want it.

[Harry Bloomfield]

Capitol was thinking very hard :

Me too :-)

9 or 10 rads, all helping to bring the temperature up, no issues with internal doors left open, the whole house usable.

[nospam]

That looks like just the job, and takes away the need to change the plumbing to add zone valves. To take best advantage of a system like this the pump either needs to be controlled by some central device that knows when any of the stats (room, DHW, towel rads, airing, whatever else) are calling for heat or has a flow switch that detects when everything's shut down. How do you control the pump on your system?

[Tim Watts]

You can zone right to the room with this:

I've had it under test - been very impressed. You can have as many or as few (even zero) rooms under direct control - the master control is an RF boiler switch that goes in place of the room stat or programmer.

I *think* the newer version of this can rely on the rad valves (where you choose to fit) to estimate the room temperature with the usual limitations. Or you can fit the room sensors.

Been very stable and very flexible - you can put it in light (say one room with RF rad valves) and add more later.

British company and very responsive to customer suggestions.

[nospam]

Thanks. Does it offer anything different to the EQ3-Max system, which seems to be a bit cheaper? Fundamental question: how is the circulation pump controlled?

[nospam]

Bah! that should have been How is the zone valve controlled (with multiple room stats)?

[nospam]

Whoops, brainfartalert, that should be: How do you control the zone valve, rather than pump.

[Tim Watts]

I don't know anything about EQ3 - sorry.

By a Single Channel Receiver - that's the bit I mentioned you replace the room stat or programmer with:

You can have more than one (for say UFH) but in the usual system, you have one and it is programmed to call for heat whenever any room (or the whole house, if you have no rad valves) requires heat.

The heating profiled is a temperature/time curve you set on a per zone basis.

You can have some zones not able to call for heat from the boiler - ie they will heat if the boiler is running for some other zone.

[Tim Watts]

A Receiver is bound to one or more logical zones.

I should also add:

If you have the rad valves, you can poke the buttons on for a local short term override to a temperature the user selects. Time is 1 hour or some other configurable value.

There's a room stat (battery, RF) that has a twisty knob on that can also cause a manual override - though this is pricier than the plain sensors.

Otherwise the only interface is via web or mobile app - but the mobile app can connect direct to your controller so if HG go out of business or their gateway fails, you don't lose your system.

It's all based on standard Z-Wave components which can mesh network (route) via any mains powered nodes - so that's the boiler Receiver in the base case - but they chuck in a 13A Z Wave plug that can be placed if you have an area in your house that's not getting good signal.

IME Z Wave manages to get around my house just fine.

[nospam]

Ah, I've found the diagrams now - so its standard S plan and presumably all the room stats can talk to the receiver. Is there a spec somewhere for how many stats and sensors the receiver will support? - I looked but couldn't find

[Tim Watts]

Regular zone valve? (HW vs CH)?

Or multiple CH zones?

The first - treat the receiver as room stat or CH progammer and wire in the usual way.

The second - I *think* you get more single channel receivers and bind them to sets of rooms in the Genius system. But with the rad valves, you can lock the zone valve open and control directly at the rads.

You can ring their tech line - they are very helpful and multiple zones (with zone valves) will have a standard solution as it's a not uncommon setup.

[Tim Watts]

If you are talking about Genius sensors - as far as I know it is effectively unlimited for any normal house. Buckingham Palace might be a problem, but I've not seen any limitations on say 3 bedrooms, 2 living areas, conservatory and hall as zones. You could ask them.