Balancing fully zoned heating required?

[Bilabong007]

Hi,

I recently installed an evohome system and have created 8 zones - one for each radiator.

As the flow is regulated by the evohome trv, should i now open all the lockshields?

Thanks

Graeme

 

[Madrab]

Balancing isn't just about regulating the heat in the radiators or room per sé, it's about ensuring all the rads heat up equally when they are all calling for heat, especially over extended pipe runs. That maximises boiler efficiency and minimises warm up time.

 

[Johntheo5]

If rads are already balanced then I would suggest leaving as is, if not, see how Evohome responds, bearing in mind that it takes a week or so to do its "learning", it works by just putting enough heat into every individually controlled rad by using a motorized valve on each rad and cycling the boiler on/off, I'm not quite sure if the motorized valve is a TRV but I'm fairly sure it is, but each room even if set to the same temperature will have its valve opening controlled by evohome, I don't know if say after 8/9 hours off at night if all the rads are then told to open 100% or do they start up with all the remembered settings, if so, a form of balancing in itself.

 

[Bilabong007]

I figured balancing was 3 fold in function
1 regulate delta t across the radiator
2 equalise flow rate across all radiators
3 regulate noise

I wonder what the effect of opening them up would have on a zoned system that modulates with heat demand. I may test it and see how it behaves.

The evo home units use the trv head and open close the valve gradually depending on demand for that zone.

The "learning" of evo home isnt up to much in my initial tests, it still over runs my bathroom by 2.5 dec C every morning without fail. To be fair its not working correctly with my boiler though, i have a thread about it and await my arduino shield to tinker with it. In fairness Ive messed that much with settings/config recently its due a hard reset to give it a stable baseline to work from.

 

[Johntheo5]

I can't really understand why they still use a thermostatic element in the HR92 or whatever, why don't they just control the valve opening without any "thermostat" as they are continually adjusting the setting anyway with the motorized valve. I've also asked the question elsewhere, what is the hysteresis (between fuly open/closed),

Re your bathroom, is the HR92 (or whatever) and the other "zones" fully open in the morning from a cold start?.

 

[Johntheo5]

Reliably informed that it works the way it should, ie NO thermostatic element.

 

[Bilabong007]

I can't really understand why they still use a thermostatic element in the HR92 or whatever, why don't they just control the valve opening without any "thermostat" as they are continually adjusting the setting anyway with the motorized valve.

It gives you a zoned sensor else you would need to connect something else to the stat to indicate conditions in the zone.

I've also asked the question elsewhere, what is the hysteresis (between fuly open/closed),

From my understanding they remain fully closed until there is heat demand.

Re your bathroom, is the HR92 (or whatever) and the other "zones" fully open in the morning from a cold start?.

I hear them opening when it starts. I can see how much each is open by checking the system status panel inside its only hidden menu. It gives a number at least, not sure what that represents though.