suitable smart control for my upgraded system

[John Driscoll]

I have a Halstead condensing boiler in the kitchen supplying HW and heating. There is only one heating zone. I have a heatmeiser thermostat/ controller in the living room. Ive never been able to get a good balance of heating over the whole house. I am now changing all my rads for column types and am thinking now is the time to buy smart TRVs and controller so I can set each room temp. I would also want time zones and HW control.
Any recommendations please. I am a competent DIY plumber and electrician.

 

[Chuck]

Unless you can pin down the reason why you can't get a reasonable balance with your existing system and traditional TRVs you are likely to experience the same problems with your 'smart system'. (None of them are smart enough to get round the laws of physics.)

I'd start by calculating the correct sizes for the emitters in each room and compare with what you currently have.

 

[ShaunCorbs]

First thing are the rads sized correctly?

As column rads are notorious for being under sized

 

[ShaunCorbs]

Great minds think alike @Chuck

 

[John Driscoll]

OK here is some more info. All rads have TRVs except the 2 in the lounge, manual valves here are fully open. This is also where the heatmieser is. This means when the lounge is warm enough the boiler switches off leaving the kitchen and conservatory etc. under heated. I'm thinking that with smart TRVs the boiler will keep fired up even if it is just one room that needs it.
On your point about column rads I have done the calcs for each room and my local supplier agrees with the figures. Are you saying I should add a % or are the output values for column rads reliable.

 

[ShaunCorbs]

I would allow 10% more and you could always turn them down but never up

Also sounds like your thermostat isn't correctly placed

 

[Chuck]

This means when the lounge is warm enough the boiler switches off leaving the kitchen and conservatory etc. under heated.

Put a TRV on one of the two radiators on the lounge and set it so that the second radiator is normally (just) shut off. By tweaking this you'll be able to find a point where the lounge heats rapidly when it is cold but doesn't starve the rest of the house once it is up to temperature.

 

[ShaunCorbs]

Put a TRV on one of the two radiators on the lounge and set it so that the second radiator is normally (just) shut off. By tweaking this you'll be able to find a point where the lounge heats rapidly when it is cold but doesn't starve the rest of the house once it is up to temperature.

Can't as the room stat is in there mate

 

[Chuck]

I'm thinking that with smart TRVs the boiler will keep fired up even if it is just one room that needs it.

I'm not sure which model boiler you have, but having a boiler driving a single radiator is not normally satisfactory. The minimum output from a typical UK condensing boiler is typically 7kW. (YMMV) This is way too much for a single radiator to dissipate so the system will start cycling on and off in a manner that will wear out the boiler and valve, waste a certain amount of gas and make the room uncomfortable.

Far better to balance the system correctly so each room gets roughly the right amount of power.

 

[Chuck]

Can't as the room stat is in there mate

There are two radiators and it is fine to have a TRV on one of them.

 

[king of pipes]

This problem often arises in modern homes there is never a good place for the thermostat you have to find what works for you, we often fit zoned heating systems in properties now it is a requirement of the building regulations, i would advise you get some proffesional advice from a good local installer to end up with a system that suits your needs and is energy efficient. Cheers kop

 

[Harvest Fields]

There are two radiators and it is fine to have a TRV on one of them.

Surely that depends on the size of the room? But I could be wrong?

 

[Chuck]

Surely that depends on the size of the room? But I could be wrong?

The thermostat needs to be in a position that it is influenced by the radiator without a TRV so that the overall control of the reference room is effective.

The modification I suggested is a tweak for an existing system where it is clear that the emitters in the lounge are so oversized with respect to those in the rest of the house that the system can't be balanced in the conventional manner

Another approach is just to turn one of them down or off using its lockshield but this is less effective than my suggestion when the weather is very cold and/or the house needs to be heated rapidly.

 

[John Driscoll]

The thermostat needs to be in a position that it is influenced by the radiator without a TRV so that the overall control of the reference room is effective.

The modification I suggested is a tweak for an existing system where it is clear that the emitters in the lounge are so oversized with respect to those in the rest of the house that the system can't be balanced in the conventional manner

Another approach is just to turn one of them down or off using its lockshield but this is less effective than my suggestion when the weather is very cold and/or the house needs to be heated rapidly.

 

[John Driscoll]

The comment about running 1 radiator was just a theoretical possibility to explain what I want. I have looked at the Drayton Wiser System. The idea is that you control via wireless all the TRVs by temperature and time zone. Then you don't need a room stat just a bypass valve in the unlikely situation that all the rads reach temperature at once. Drayton engineer says you can turn it off.

 

[Chuck]

The comment about running 1 radiator was just a theoretical possibility to explain what I want. I have looked at the Drayton Wiser System. The idea is that you control via wireless all the TRVs by temperature and time zone. Then you don't need a room stat just a bypass valve in the unlikely situation that all the rads reach temperature at once. Drayton engineer says you can turn it off.

My solution costs about £20, can be installed by DIY in an hour tops. I have no financial incentive to sell it to you.

The Drayton solution...