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Ecodan with FTC7 - True Weather Compensation

danwright90 · 2026-01-06T11:20:43Z

Hi I have Ecodan 6kw with FTC7 packaged cylinder setup on two zone with EPH zone Values to control room temperature. Over the 6 months the COP was 2.5 for space heating. Taking advice from various sources, i wanted to see if i can improve the COP by lowering the weather compensation. After few days of trial and error, i found that FTC7 actually does not run on pure weather compensation and requires wired or wireless thermostat for each zone to provide room feedback/temperature. (which i dont have) Looking at the zones on the FTC7, it is using its internal thermostat sensor for a reading/feedback. The issue is the FTC7 housed in cupboard and using room thermostat it, it is at 28c. Looking for your help on what to do next. My thinking is to purchase the Ecodan wireless receiver, room thermostat and MELCloud Hardware to allow the system see the true value but also give me more data on how the system and should improve the COP.

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Air Source Heat Pumps (ASHPs)

Last Post by Sheriff Fatman 5 months ago

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JamesPa

(@jamespa)

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06/01/2026 3:20 pm

Posted by: @danwright90

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I hold off for now with the hardware but i may still get the MELCloud receiver as this would give me flow temperatures as right now, i am in the blind.

Some data is definitely useful. I ordered the internet connection for my Vaillant heat pump and use Home assistant to pick up some basic data because, unlike Mitsubishi, there is no graphical online portal and the app doesn't present much graphically. It has got me out of a couple of holes and proved useful in helping others also!

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.

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danwright90

(@danwright90)

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Topic starter 06/01/2026 4:15 pm

@jamespa

Thanks James

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Sheriff Fatman

(@sheriff-fatman)

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06/01/2026 4:29 pm

Posted by: @danwright90

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I hold off for now with the hardware but i may still get the MELCloud receiver as this would give me flow temperatures as right now, i am in the blind.

I would definitely suggest a solution to give you system data is useful, if not essential for identifying issues. I'm not sure what the MELCloud receiver costs to purchase, but the MELCloud app itself is very limited in what it provides. There is potentially one specific alternative option available, which is a dongle device produced by one of the forum users, @f1p, which sells for around £35 and which plugs into the same connection, the CN105 port, that the MelCloud adapter would use.

The information you can get from this, either via Home Assistant, or the MelPump app, is far better for the end user, so it is potentially an inexpensive alternative. For info, the graph data I included in my original reply was from the MelPump app. I was initially sceptical about being able to install it, but had help from @f1p and @majordennisbloodnok via this forum. From your current point of lacking the wifi adapter for MelCloud, I suspect that this might prove to be a better option at lower cost. (NB: just checked and it looks like the Mitsubishi option is around £100-£120 to purchase, so I definitely think this would be the case).

Separately, I think there is a way for you to see real-time flow temperatures within the FTC7 controller, possibly within the installer settings, from memory. I'll see if I can include how to do this in a video clip too. You'll only get a real-time snapshot of the sensors at that point in time, but it sounds like that's better than nothing currently.

This post was modified 5 months ago 2 times by Sheriff Fatman

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

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DavidAlgarve

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06/01/2026 5:03 pm

Posted by: @danwright90

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The installers are registered, highly recommended, so i do trust the install.

As you appear not to be too comfortable with how it has been set up, do the installers have anything to contribute?

With the multiplicity of additional controls, I am not sure how the weather compensation performance can be evaluated. It sounds a bit like how I started with all radiators having Tado SRV's

342sq m "Upside down" house in Algarve. Portugal
Mitsubishi PUHZ-120YUK 12kW ASHP
12 Solar Panels Growatt Inverter
2 x Growatt 7.5kW Batteries
Fronius EV Charger
Kia e- Niro 64kW

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Sheriff Fatman

(@sheriff-fatman)

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06/01/2026 8:42 pm

@danwright90

I've linked two videos below recorded this evening, one for getting flow temp info and another for you to check that your weather compensation settings are all set correctly (i.e. where the various functions are, rather than copy exactly what mine are doing). Hopefully they're of use as an initial sense check. I've uploaded them via Vimeo, as they're too large to post directly on the forum.

Getting Flow Readings

Weather Comp Settings

This post was modified 5 months ago 12 times by Sheriff Fatman

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