im assuming that each reciever is wired using S Plan to the zone valve and the master Controller modulates the boiler accordingly in Star like topology
I'm wondering if you can plug multiple smart thermostats the way that they will be supporting opentherm ? So instead of cabling one thermostat to OT port of the boiler, you could wire two or more thermostats relays to that OT port ??? Like multiple Nest controllers etc ??? What do you think ?
Hi Allen, this looks to be just what I’ve been looking for. Can we have more details (maybe a dedicated video?) on converting S plan to OpenTherm in this way? I’ve looked on EPH’s website but can’t see anything relevant (perhaps my GoogleFu is weak!). What cylinder stat would be used? How far away can the receiver bixes be from each other? (Ideally I’d like to put the OT connected box next to the boiler to limit the low-voltage cable length). And would it be possible to implement PDHW in this way, perhaps by making the OT-connected receiver the master? Looking really interesting, but not quite enough details yet...👍
Hi Alan, I have Eph hub installed In conjunction with an Ideal 35kw gas combi boiler. Is it possible to control the flow temperature of the water remotely?
Hey.. I've just bought a new combi boiler chappee initia plus hte 2.40 which is equivalent to baxi luna duo tec plus 2.40 and a nest learning thermostat 3rd generation, made sure have all the opentherm conmections tight and where it should be conmect yet keep getting error ' H73 heat link couldn't detect an open therm connection.." please advise... As well made sure the boiler do support an open therm the conmect to the board similar to baxi 600 on M2 ports 1 & 2. Many thanks.
How can u have OT data & mains in the same cable? The surely need to be separate & the OT conductors screened with CY cable or similar? Other than that it looks great
it looks like the same cable, as it leaves the main controller, but looking at the boiler you can see they are separate, would be better if the wires were separated at the control.
@@robertwhite4919 do you mean that the 2 seperate cables would leave the control through 2 seperate openings in the plastic control housing instead of 2 cables through one openjng?
@@justinklrjms the origin question was about the single cable, but as you say it is two cable in the same hole which wasn't clear on the video, it is usually good practice to keep the data and mains connections separated. As mentioned screening may be required and not good to run data cables along side mains cables as can cause interference, should all be in the installation manual.
Is a wireless cylinder thermostat in an S plan like this compatible with regulations for an unvented cylinder? Thought it had to have a thermal overheat sensor.
You'd need a HW tank with 2 sensor pockets. One for the HW-OT RF connection back to the boiler for Open Therm HW temp modulation. The other sensor would be a standard overheat type linked into the S plan wiring. G3 doesn't allow just one thermostat to both control HW temp and also act as thermal cut-out.
Evening mate, I'm struggling to understand this, what is the difference between have this and just 3 separate stats on 2 ports with switched lives going to the combi? What is the difference with open therm other than low voltage?
OpenTherm is an open protocol which any manufacturer can use. This gives a wide range of third party devices to use, giving competition and choice. Connecting an Opentherm thermostat to a boiler which is OpenTherm compatible means you have *load compensation.* That means the burner will _modulate_ to maintain the room temperature setpoint. No inefficient on-off boiler cycling. This setup has one master thermostat/controller which is connected to the boiler, with all others off this, giving one master -> many slaves. The boiler will output the highest temperature that any of the controllers call for. If say 4 zones are calling for, 1) 40C, 2) 45C, 3) 50C and 4) 65C. The boiler will output 65C. If zone 4) is demanding 65C, then quickly demands 35C, the boiler will then output the temperature demand from the highest calling zone which is zone 3) at 50C.
@@johnburns4017 This system is pretty unique at the moment. The central hub is adding up the heat demand (in degrees) from multiple zones to get a total heat demand that it sends to the boiler. Most Opentherm implementations on take the demand from one zone and send it to the boiler which means the boiler isn't producing enough heat to satisfy the demand from the remaining zones.
@@tlangdon12 It looks like it is only taking the highest demand from any of the the zones, not the total. In reality in a typical home, there should not be that much difference between the zones. When the house is up to temperature demand will be low as the _average_ setpoint between them all is near reached. Zones will be switched in and out as setpoint is reached and temp falls below setpoint. If a zone is off being cold, with the other zones near setpoint, lowering the burner output, then the cold zone is switched in, as that zone is demanding more heat (hotter boiler temp) then the temp fed to all other zones rises. But the local zone controllers should close off those zones when their own setpoint is reached. The slave controllers switch a zone valve only - on-off. The master takes the highest temp from any of the slave controllers then uses that at the setpoint target for the boiler temp. That is how I see it. With some boilers when setpoint is reached via OpenTherm, they can de-energise a zone valve (switch it on-off). I am having difficulty grasping how the master controller switches in and out a zone valve for the zone it is controlling. *a)* Is it the master controlling a heating zone it is located (switching a zone valve)? and; *b)* A _master_ cum _relay,_ in relaying the highest temp read from the slaves back to the boiler? The master *looks like* it is serving *two* functions: *1)* Switches in & out its own zone valve controlling the zone it is located in. *2)* A relay, relaying the highest slave temps including its own back to the boiler. I like this system. It looks simple and cheap enough.
@@johnburns4017 It’s difficult to know exactly what is happening without looking at the OpenTherm signal, or without the manufacturer being open about it. I think manufacturers are missing a trick in not making their logic available to those of us who are interested.
Suppose its all subject too opinion i just believe aesthetically they have let themselves down a bit. It looks no newer than an old honeywell 2 channel
@@AllenHart999 It is normal terminology in commercial control, of which I was in. Being domestic focused maybe terminology is changed to make it easier for _plumbers_ to understand.
