To get it working you also need a twin and earth cable from the ASHP immersion heater output to go into the e-sense port on the Eddi.
If you have 2 x 2 core cables you “could” use one for the smart grid relay and one for the immersion port as you will not be pulling any current through it and you only need a live and neutral for the e-sense. The actual power is pulled from the Eddie’s main power input.
That would allow it to work with full smart grid and immersion from the madoka.
Can i jump in here Zak?
I’m just researching this as we install heat pumps but this will be the first time we have included a solar diverter.
The solar guy is just going to rock up with one and I presume will expect us to fit it.
So I have read through this and can you confirm i have my understanding right.
So, you have the immersion wired to the eddi.
the heat pump triggers the immersion my wiring the immersion control to the eddi on the external trigger, i get that. So when the disinfection cycle hits, the heatpump asks the eddi for the immersion and turns it off when it completes.
moving on to the excess solar…
so
the eddi senses the excess solar and activates the smart grid interface.
the heatpump receives the signal and starts heating the water via the air to water.
the heat pump has ob-115 meter installed on the incoming tails and is aware of the excess that is available.
the heat pump modulates to keep its operation within the excess.
correct so far?
now for questions.
what happens when the water stored water temp reached 45 degrees, or what ever you have set for the setpoint, does it cease to heat further? or can it be configured to bring the immersion in?
my thinking is that the hotter the water (60 odd degrees) the more thermal mass we have saved?
or is this where the eddi comes in, will the heat pump bring the immersion in? will the heat pump shut down because the stored water is at 45 degrees, the eddi see a large excess now and bring the immersion on its self and increase the water temp? and does the madoka/MMI ever get in a pissy if the water temp is rising without it being commanded to?
alot of questions, but all valid i believe.
Many thanks
Hey Daniel,
I can’t remember the setting off hand and am out of the country for a few days but the dhw had a setting allowing it to overheat and buffer a little. Also if the ASHP stops the Eddi can and will take over providing the settings on the Eddi allow it to heat that hot.
You also need an immersion with an adjustable stat on the back (usually red knob). This allows you to set a max temp cut out and not have a scalding hot tank of water one warm Thursday afternoon.
Your other assumptions are correct. Have you seen the Google docs and do you have any other questions let me know.
Zak
awesomely quick reply there Zak.
you continue your holiday. i’m going to have a think and a ponder. i may even draw up a wiring diagram to check its correct.
speak soon
Your Word doc has been great - Thanks for putting that together 
One follow up question please as i have been put into a similar position with my install last week - i have however managed to get Octopus to run a spare 4 core.
I’m OK with the connections for relay 1 and the X5M on the Heat Pump, but do you have a picture of the connection on the Heat Pump for where the e-sense (immersion heater output) cable comes from please or know whereabouts it’s connected?
Thanks
The heatpump has an immersion heater output on the actual outdoor unit.
In a traditional Install this is how the ASHP triggers the disinfectant cycles (immersion heater).
This is x4m on the edla04-08 range and uses 2.5mm 3 core cable. The live and neutral go to the e-sense ports in the Eddie relay board and earth to the earth in the Eddie (for safety).
Then you set the Eddie to boost when it sees power and it will see power when the ASHP requests a boost (when it tries to trigger the immersion).
You are just keeping the immersion function and scheduling of the heat pump and adding in the solar diversion and the relay boards and smart grid allow the ASHP to trigger.
Makes sense and that is how it needs to work. I have just opened up the HP and confirmed they have at least installed the X4M module which is good (wasn’t sure they would have given it is optional and i never had the immersion wired via the HP as in a “traditional install” as you say) and i have now wired the e-sense to the X4M module (e-sense 1 to X4M N & e-sense 2 to X4M L).
As a first test, I changed the e-sense in the Eddi settings to boost. Went into the Madoka and set the boost heater to 3Kw and turned it on to legionella only. Went to the disinfection menu, turned action to yes and set a cycle to start in 1/2hr time for 30mins.
The time came but the eddi did not switch on the immersion. Turned the disinfection off. Went back into the Booster Heater Operation to “allowed” and turned on the boost function in the app, still no switching on the immersion by the Eddi. The boost mode should run both the HP and Immersion at the same time, but only the HP was running.
Could i please check - I know your Eddi is powered of your existing Consumer Unit, but do you still have a seperate 240v supply wired in and turned on for the Immersion at the HP? Think it should go via the K3M relay (2&4) or do you have this disconnected?
Thanks
Both the ASHP and the Eddi are powered from the main consumer unit in the house and have power 24/7.
The immersion heater has one twin and earth wire connected to the heater 1 output of the Eddie
The immersion output on the ASHP is wired into the e-sense port in the Eddi.
When the ASHP triggers the immersion it sends 240v (this would normally be the power supply wired directly to the immersion) the Eddi “senses” the 240v and then if set to boost should trigger the immersion heater (unless it is already hotter than the temperature limit from the pt1000 OR hotter than the cut off on the immersion element)
This confirmed my issue. As I don’t have an existing 240v power supply at the HP for the immersion circuit, i’ve had to piggy back off the main incoming 240v inside the HP to put power to that K3M relay, so it can sense 240v, and it now switches the immersion on via the eddi connected to the X4M module. Not the ideal way to power it but i’m not putting in another MCB to supply that relay when it’s not actually drawing any power and only being used for voltage sensing.
Got there in the end - Thank you for your help