Joining the Renewable Heating Hub forums is completely free and only takes a minute. By registering you’ll be able to ask questions, join discussions, follow topics you’re interested in, bookmark useful threads and receive notifications when someone replies. Non-registered members also do not have access to our AI features. When choosing your username, please note that it cannot be changed later, so we recommend avoiding brand or product names. Before registering, please take a moment to read the Forum Rules & Terms of Use so we can keep the community helpful, respectful and informative for everyone. Thanks for joining!
Melpump Users Anywhere?
Posted by: @f1p...
I don't think either will take precedence, it is last received.
...
Thanks, @f1p. My issue with understanding is a matter of what's being changed and how - something I don't know, so in need of illumination.
It seems to me a matter of whether we're talking about an event or a state, and forgive me if I oversimplify my explanation for the benefit of non-coders who may also be reading.
If there's a schedule to trigger an event - like "start heating the hot water" - then understandably that action will start when the trigger is hit either by the local schedule or the Internet one, whichever happens first if both want to try controlling it. If that schedule is only an Internet one and the trigger can't be sent to the heat pump for some reason (e.g. Internet connectivity issues), the heat pump won't do anything when it and the Internet can see each other again. However, if that event puts the heat pump in a particular state (e.g. holiday mode), when the heat pump can talk with Melpump/Melcloud again the two will synchronise that state in one way or another so that either Melpump/Melcloud recognises the pump should be in holiday mode and updates the state retrospectively or the heat pump knows it's not in holiday mode and tells Melpump/Melcloud to sort itself out to reflect this.
For various schedules, I simply don't know if it's events or states that matter (probably sometimes both) and, if it's a state needing to be synchronised how the precedence will work.
Of course, I may be overcomplicating things here. It wouldn't be the first time.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
Posted by: @majordennisbloodnokwhen the heat pump can talk with Melpump/Melcloud again the two will synchronise that state in one way or another so that either Melpump/Melcloud recognises the pump should be in holiday mode and updates the state retrospectively or the heat pump knows it's not in holiday mode and tells Melpump/Melcloud to sort itself out to reflect this.
Okay, thanks for explaining - it would be the former. The heat pump current state is always reported actual, regardless of attempts to change it.
- Both in my adapter and the official MELCloud adapter there is retry logic, to compensate for potential write failures caused by a rejection in the FTC as it could reject the command when "busy" or a malformed packed in the serial communication (due to electrical interference for example) and it is limited to a fairly conservative quantity.
- MELPump and Home Assistant both work in a optimistic approach, where the change is considered successful until proven otherwise (confirmed by the next read)
- I don't have evidence to suggest that MELCloud has any retry logic if the command was unable to reach the heat pump due to a connectivity issue
- MELPump has retry logic, where if that optimistic state was proven unsuccessful shortly after it will perform another attempt
Anyone else having issues getting Melpump to display their 'interactive' charts via the Share as URL option?
I'm just getting a blank page, other than for the summary coloured sections at the bottom. I was hoping to use one in a forum reply, but it would be of no use currently.
130m2 4 bed detached house in West Yorkshire
10kW Mitsubishi Ecodan R290 Heat Pump - Installed June 2025
6.3kWp PV, 5kW Sunsynk Inverter, 3 x 5.3kWh Sunsynk Batteries
MyEnergi Zappi Charger for 1 EV (Ioniq5) and 1 PHEV (Outlander)
User of Havenwise (Full control Jun-Dec 2025, DHW only from early Dec)
Subscriber to MelPump App data via CN105 Dongle Kit
- 27 Forums
- 2,746 Topics
- 64.5 K Posts
- 1,524 Online
- 7,149 Members
Join Us!
Installer Finder
Degrees of Separation
Latest Posts
-
Have you considered keeping your FF boiler and suppleme...
By Old_Scientist , 2 hours ago
-
RE: Who's your electricity provider and what's your tariff?
@toodles I invested on Miele a pair of frodge frozor wh...
By AgentGeorge , 3 hours ago
-
RE: Flushing system, cleaning and inhibitor
Flush and fill all complete. Octopus kindly gave us a...
By Old_Scientist , 4 hours ago
-
RE: Wood burner with ASHP - direct air?
For what it's worth I installed a wood burner in this o...
By BlizzardGreen , 5 hours ago
-
@editor Thanks for your response and recommendations. ...
By DavidB , 12 hours ago
-
RE: Do I add Air Con or MVHR to existing A2W ASHP?
I think I saw a diagram for an exhaust air dhw tank wit...
By JamesPa , 1 day ago
-
RE: Indevolt Batteries UK Support & Info Thread
Thanks, however that's an answer to a subtly different ...
By JamesPa , 3 days ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
@toodles Such elegant symmetry. look at my lumpy bag of...
By Papahuhu , 4 days ago
-
RE: PV and battery long payback - sense check query
Quite probably not, but you can get a 32A relay and a S...
By JamesPa , 4 days ago
-
RE: Starting Our Heat Pump Journey: 1962 build 3 bed detached house
@ian-s Look forward to making contact soon! Regards, To...
By Toodles , 4 days ago
-
I don't notice mine defrosting, and most of the time Im...
By JamesPa , 5 days ago
-
RE: Do I need to change the control unit when replacing my Ecodan Air Source Heat Pump
Kind of you, @calumm, but it was @f1p who did the heavy...
By Majordennisbloodnok , 6 days ago





