Worcester Bosch Greenstar Modulation

My last house was open plan, upstairs would over heat at times, so TRV heads fitted upstairs, non down stairs, old boiler so did not modulate, but it worked well so never considered how to improve, as worked well, only when moving to mothers house did I actually look at control as it didn't work very well.

The thermostat fitted was wrong for system 84067_P.jpg a very good thermostat for a non modulating boiler, it had built in fail safe, and as it approached the target temperature it started a mark/space (on/off) sequence so it did not over shoot, however with the modulating boiler that in essence stopped it modulating, every time it switched off any heat in boiler went out of flue, and at each restart it starts at full output, so boiler ran hotter so more waste out of the flue.

Also fitted in the hall, so open front door and hall was cold, close it and to reheat radiator was large, but if door not opened it would heat hall and turn off boiler, with rest of house cool, cure was a TRV on hall radiator set so it turned down radiator before target was reached, so fast recovery but did not stop rest of house heating.

But the big question is how much difference is there in energy used with a carefully tuned system compared with one turning off the boiler every 5 minutes, or 10 minutes, or 30 minutes or an hour?

I wanted a gas smart meter so I could see minute by minute how much gas used, but they would not fit one without also fitting an electric smart meter, and no way was I having one of them.

So it is pure guess work, I suppose you could count how many times the condensate pump runs, this would show if the boiler is getting the latent heat, but I think it is likely so little not worth bothering about. OK you like me have a silly Worcester Bosch boiler which does not allow the use of third party modulating thermostats, the EPH is only one I know which can work OpenTherm with zone valves and they are configured as master/slave. But what ever system is used, it costs to install, likely best with Worcester Bosch boiler is Hive, but that will not work with zone valves, they would need to be powered together, and the Hive TRV heads would switch sections on/off as required, so you would need to fit all radiators with TRV's and Hive wall thermostat plus the TRV heads and looking at around £500, if it saves 10% then with interest on money invested we are looking at 15 to 20 years to break even.

I can turn off a room at a time, middle floor (bottom floor not used) if I turn off dinning room it will cool to around 14°C but the insulation between rooms is not good enough for it to cool any more, top floor and 16°C with heating turned off, simply insulation between rooms is not good enough to result in much saving. With my bedroom the TRV 61dmtMm13BL.jpg turns down during the day, set to 16°C but it rarely cools to 18°C so at 2°C is it really worth the cost of the 2 AA batteries used per year?

What we have to remember adverts lie, we watch a Freddy Boswell look alike clapping his hands and the lights going on/off because he has fitted a smart meter, that is impossible, there is no way for the user to turn a smart meter on/off, only the supplier can do that, and I would not want lights to go off every time I clapped my hands.

It is unlikely any alterations to control will save enough to be worth it, so only alterations which make it more comfortable are really worth while, OK exceptions to every rule, daughter lived in a listed building with no wall insulation and no double glazing and yes timers on heating helped. Originally it was heated by keeping cows down stairs, not really an option today, but in the main children today have never seen what jack frost would pain on the windows.
 
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You just have to accept, that you have an S plan system, installed correctly and your model boiler can only do boiler modulation
Fair enough. It's a shame, I was hoping the Tado or some system could do this:
upload_2021-11-5_16-0-17.png


A nest "heat link" or tado wireless kit that communicates with thermostats around the house. Replace the existing thermostats with the nest/tado wired thermostats, change the voltage to 24V or whatever they need.

Thermostats or smart TRVs could be responsible for wirelessly communicating with the heat link that their zone needs heat. The heat link could open the valve. It would also supply live to the microswitch, and look for 230V returning to LR1/LR2 to confirm that valve is definitely open.

Then use the EMS bus to modulate heat properly. The only challenges would be if zone 1 wanted more heat than zone 2, but the boiler could provide the higher flow temperature to zone 1 and fall back to TPI/"PWM" to modulate zone 2.

Seems like it'd be really easy to wire too with the existing wires.
 

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