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Hello all,
I'm looking for suggestions on heating controls.
We'll be upgrading our boiler (To a modulating oil system boiler - EOGB Sapphire) and unvented cylinder (To a Mixergy cylinder) as we currently have a 13 year old fixed output combi boiler with a unvented cylinder which is fed solely via our thermal solar (Resol DeltaSol BS Plus controls) - Meaning that we need to use the immersion for hot water in the winter. (The combi solar diverter valve is very inconsistent when the cylinder water is cold and I believe a combi is no-good for killing Legionella from a cylinder due to the short path the water passes through the boiler)
The Sapphire boiler requires OpenTherm controls - Not just to take full advantage of it, but because it doesn't support traditional controls at all. We'd also like to take advantage of hot-water priority so that we can have lower radiator flow temperatures. (We'll upgrade some undersized radiators for now but full underfloor is on the cards in the future, once we knock down some walls and complete our renovation) We'd also like to try steady state heating with weather compensation.
We currently have a Nest thermostat (Gen 3) which does support OpenTherm, but it is quite limited in what you can do with it. I'm not sure it can do hot water priority, or at least I can't see any configuration for that. Additionally it doesn't do proper weather compensation - You can't configure anything and it relies on internet weather sources which are not accurate enough for this location.
EOGB suggest the use of Honeywell Evohome controls. This appears to be slightly more configurable but still hides a lot away from you and also does not have a local weather sensor. I'm also not a massive fan of everything being wireless, I'd rather have it all hard wired for a heating system.
I'm a programmer by trade so in the end, I may pull out a microcontroller and produce my own controls - Copying ideas from Vaillant's offering. That however will take time to perfect so I'm looking for something to get started with. (And of course if it's any good, we'll just keep it)
I'm looking for suggestions on heating controls.
We'll be upgrading our boiler (To a modulating oil system boiler - EOGB Sapphire) and unvented cylinder (To a Mixergy cylinder) as we currently have a 13 year old fixed output combi boiler with a unvented cylinder which is fed solely via our thermal solar (Resol DeltaSol BS Plus controls) - Meaning that we need to use the immersion for hot water in the winter. (The combi solar diverter valve is very inconsistent when the cylinder water is cold and I believe a combi is no-good for killing Legionella from a cylinder due to the short path the water passes through the boiler)
The Sapphire boiler requires OpenTherm controls - Not just to take full advantage of it, but because it doesn't support traditional controls at all. We'd also like to take advantage of hot-water priority so that we can have lower radiator flow temperatures. (We'll upgrade some undersized radiators for now but full underfloor is on the cards in the future, once we knock down some walls and complete our renovation) We'd also like to try steady state heating with weather compensation.
We currently have a Nest thermostat (Gen 3) which does support OpenTherm, but it is quite limited in what you can do with it. I'm not sure it can do hot water priority, or at least I can't see any configuration for that. Additionally it doesn't do proper weather compensation - You can't configure anything and it relies on internet weather sources which are not accurate enough for this location.
EOGB suggest the use of Honeywell Evohome controls. This appears to be slightly more configurable but still hides a lot away from you and also does not have a local weather sensor. I'm also not a massive fan of everything being wireless, I'd rather have it all hard wired for a heating system.
I'm a programmer by trade so in the end, I may pull out a microcontroller and produce my own controls - Copying ideas from Vaillant's offering. That however will take time to perfect so I'm looking for something to get started with. (And of course if it's any good, we'll just keep it)
