Multi-sensor controls

[fundibomba]

I have a large house divided into 9 individual rented small flats with a communal central heating system system. The boiler is a Worcester 30SE which works fine - the radiator sizing and pipe sizing seems to have worked out fine and the rooms stay reasonably evenly warm even when very cold outside.

Relying on radiator thermostats is a waste of time as the tenants do not mange them reasonably.

Current control is a single wall thermostat in the communal stairwell. The radiator in the hall is sized to keep the hall at 17 deg C when the flats are at 20 deg C. So I put the hall stat at 17 deg C and that keeps the flats at 20 deg C. This is fine when it is cold but suboptimal when it is warm. I think the hall is naturally the coldest part of the house when it is warm outside so the system comes on when it does not need to.

I think it needs thermostats in each room with a central controller which averages the readings or something like that. Any ideas? Presumably public buildings like schools with heating via radiators have the same problem.

 

[Agile]

Schools are not run by mean landlords. Teachers like to keep warm!

My immediate concern is that 20° is a bit cool when the recommended is 21°C.

Here its 21.7° at the moment and more often about 22.4° at this time.

My interesting question is why dont the cooler tenants turn the hall stat above 17°?

Tony

 

[fundibomba]

You are right Agile - design temperatures for living areas should be more like 22 than 20.

I checked the design and actually the design temperature was 17 deg C in the stairwell and 22 deg C in the flats against an external temperature of -2 deg C. I have no complaints from tenants so am reasonably sure the design is being achieved without stretching the boiler.

The hall stat is in a tamperproof enclosure.

As I said the issue is that the system keeps going even when it is warm outside because the hall stays cool in summer. So economies could be made outside the coldest part of the year.

 

[mickyg]

surely if the tenants are too hot they'll quickly work out how them trvs work?

Otherwise you'll have to go for something pricey like the CM zone system. If they can't work out a trv no point putting any other controls in the rooms!

 

[Agile]

surely if the tenants are too hot they'll quickly work out how them trvs work?

That sounds as if you have never been a tenant !

They are more clever now anyway!

They just open the window if its getting too hot. Gives then some fresh air too!

Tony

 

[londonboy]

Ive worked on large properties like this before and the fitters installed a two port and programmable roomstat in each flat.

Therefore making each flat independant so they can all be at different temperatures.

 

[Onetap]

If the heating is on 24/7, I'd look into installing a weather compensating system; this would vary the flow temperature, and so the heat output according to the outside temperature. I don't know if it's available for a WB boiler.

A sensor in each flat and electric-thermo actuators on the rads would work, but the wiring would be a major problem.

 

[fundibomba]

Thanks very much for your comments.

Londonboy - I did consider separate controls in each flat on installation but rejected it due to complexity - particularly as we couldnt use conventional 240 volt controls as each flat has its own mains supply and you shouldn't mix different mains supplies in the same area.

Onetap - this does look like the answer - you can get a "FW 100 weather compensator controller" which should work with our boiler. This uses two thermostats one sited on an outside wall and a second one inside the unit itself. However its not clear whether you can disable the internal thermostat and use a remote thermostat in the stair well to control the temperature inside the house. The information on the web site is unhelpful. I suppose I will have to try ringing WB.