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!
Mitsubishi Ecodan - Hot Water Settings
Hi all,
Partner and I moved into our new build back in Aug 22 and have hated our Ecodan ASHP pretty much since August 22. We've had multiple 'engineers' come out to sort the settings but they all recommend different things, the house remains cold and the smart meter is always ridiculously high. But those settings are far another time...
My main query is that for reasons unknown whenever I know the hot water is on and I check the main controller that sits in the airing cupboard and the lightning symbol always seems to be on. From what I understand that means the backup immersion is kicking in...but why? I understand that the ASHP might not have the capability to heat the water above 45'c etc without backup from the immersion but the immersion will be on even when the tank temp is down in the 10's/20's.
Is this how they're designed or is this a setting? I'm assuming constantly using the immersion is not the most efficient way to heat the hot water tank...
Matt
Posted by: @walsham_mattHi all,
Partner and I moved into our new build back in Aug 22 and have hated our Ecodan ASHP pretty much since August 22. We've had multiple 'engineers' come out to sort the settings but they all recommend different things, the house remains cold and the smart meter is always ridiculously high. But those settings are far another time...
My main query is that for reasons unknown whenever I know the hot water is on and I check the main controller that sits in the airing cupboard and the lightning symbol always seems to be on. From what I understand that means the backup immersion is kicking in...but why? I understand that the ASHP might not have the capability to heat the water above 45'c etc without backup from the immersion but the immersion will be on even when the tank temp is down in the 10's/20's.
Is this how they're designed or is this a setting? I'm assuming constantly using the immersion is not the most efficient way to heat the hot water tank...
Matt
I would suggest looking at all the settings, particularly the ones in installer mode. If you are not certain if any settings are correctly optimised then post the details and someone will try to advise.
In the Auxiliary Settings there is a 'Electric Heater (DHW) setting that is on with a delay. I'm assuming that might be it?
But if I turn this on will the hot water be able to get up to 50'c via the ASHP alone?
Posted by: @walsham_mattIn the Auxiliary Settings there is a 'Electric Heater (DHW) setting that is on with a delay. I'm assuming that might be it?
But if I turn this on will the hot water be able to get up to 50'c via the ASHP alone?
I think you can turn your immersion off with this setting but I don't know why it's on in the first place. My Ecodan heats to 55 deg easily in all weathers so not sure why yours doesn't.
Posted by: @walsham_mattthe house remains cold
Posted by: @walsham_mattI understand that the ASHP might not have the capability to heat the water above 45'c etc without backup from the immersion but the immersion will be on even when the tank temp is down in the 10's/20's.
I can sense your frustration with the equipment and are looking for a quick solution but these issues may be connected in some way.
So it would help to have a fuller picture of what you’ve got and how the DHW settings have been configured.
Can you access the DHW edit screen. If you can it would help to post all the settings that are currently set.
how to access :
1. press and hold the menu button for 3 seconds until the ‘secret’ edit menu is revealed ( it has black arrows on white buttons instead of white arrows on black buttons). See pictures
2. Press the tick to select the highlighted tap symbol
3. select the DHW NOTEBOOK symbol to reveal the list of DHW settings.
4. pick each item individually to reveal what it is set at. (6items)
if you can post this data it may reveal something more obvious.
please also confirm :-
size of heat pump and cylinder
wherher cylinder is the pre-plumbed Mitsubishi unit
anything else that might be useful information. Does it switch itself off repeatedly etc.
What thermostat eg third party or Mitsubishi wireless or other.
How many radiators or underfloor or both
It might seem like a lot to ask but Somebody in these forums may know exactly why this is happening with the right information.
hope this helps
@kev-m I turned this setting off by I'm still getting the lightning bolt symbol appearing.
I'll go through all the settings and post tonight. Hopefully someone better than I can help. Shame Lovells who installed the system are so unwilling to assist.
@walsham_matt Lovells almost certainly subcontracted it to an installer. That may be who to talk to, or they may be hopeless but cheapest bid.
I was sadly watching my ASHP tonight and it's left me with more questions than answers.
I'd switched off every immersion heater setting I could find in the hope it would force the DHW to heat via the pump.
End result...2 hours of cycling between ASHP and nothing at all showing on the controller. In the space of 2 hours it went from 17'c to...17'c.
The odd thing about it was that within the cupboard there is a red hot pipe so the ASHP is doing its job but it's not getting to the DHW tank.
I'm guessing this is an installation issue rather than anything else? I've emailed Lovells and hopefully get an 'engineer' out in the next week or two.
Posted by: @walsham_mattI was sadly watching my ASHP tonight and it's left me with more questions than answers.
I'd switched off every immersion heater setting I could find in the hope it would force the DHW to heat via the pump.
End result...2 hours of cycling between ASHP and nothing at all showing on the controller. In the space of 2 hours it went from 17'c to...17'c.
The odd thing about it was that within the cupboard there is a red hot pipe so the ASHP is doing its job but it's not getting to the DHW tank.
I'm guessing this is an installation issue rather than anything else? I've emailed Lovells and hopefully get an 'engineer' out in the next week or two.
I would suggest that you check that the valve or valves are changing over from central heating to DHW heating.
Edit.
I suppose that the other thing to check is that the temperature sensor is actually installed correctly on your hot water cylinder.
-
How Accurate Is My DIY Heat Loss Calculation?
1 month ago
-
Surface mount or bury primaries for heat pump installation?
1 month ago
-
Do I need to change the control unit when replacing my Ecodan Air Source Heat Pump
2 months ago
-
Issue with Samsung Cascade System
2 months ago
-
New Vaillant Arotherm Plus 7kW (cooling enabled) + Jaga Briza cooling + Sunamp Thermino – costs, experiences & Sunamp choice (EnerPHit-level retrofit)
3 months ago
- 27 Forums
- 2,787 Topics
- 65.8 K Posts
- 3,913 Online
- 7,192 Members
Join Us!
Installer Finder
Degrees of Separation
Latest Posts
-
RE: Home energy storage & battery register
A useful register should record model, usable kWh, inve...
By EnergyStorageTech , 2 hours ago
-
RE: Replacing Storage Heaters with a Heat Pump in a Stone Cottage
I assume the 2.5 - 3kW required to heat the hot water c...
By Paul1098 , 4 hours ago
-
RE: Vaillant ecoTEC Plus - Flow Temp and Set Up
@trebor12345 I have been meaning to get home assista...
By Batpred , 6 hours ago
-
RE: Adding additional Solar Panels to a DC coupled battery system
@transparent I was replying about the accuracy of "AI" ...
By EtchedPixels , 8 hours ago
-
RE: Indevolt Batteries UK Support & Info Thread
SunSynk hybrid inverters also have the capability to as...
By Transparent , 9 hours ago
-
RE: Is This Initial Free Quote From Octopus Trusted Partner Reasonable?
If you've got a sash window or a door you can remove th...
By EtchedPixels , 10 hours ago
-
RE: Heat Geek Zero Disrupt: Are We Sleepwalking Into Another Race to the Bottom?
Roughly how most air/air is done except that step 3 doe...
By EtchedPixels , 10 hours ago
-
RE: Nook batteries from Octopus
@batpred If your energy use is low enough that just get...
By EtchedPixels , 10 hours ago
-
RE: Missing flow temperature in Heat Geek proposal
I suspect 4 yrs ago, their approach had not got to this...
By Batpred , 11 hours ago
-
RE: battery storage without solar
Also don't forget that in you may not be able to use th...
By JamesPa , 21 hours ago
-
RE: Tesla Powerwall (2) Calibration Cycles
One practical safeguard is to separate the calibration ...
By EnergyStorageTech , 22 hours ago
-
RE: tepeo ZEB UK Support & Info Thread
There is at least one large scale system in this catego...
By Toodles , 1 day ago
-
RE: Getting closer to a finished Haier system
Apart from sealing the external Primary Pro joints and ...
By Singlespeed , 2 days ago
-
RE: Air-to-Air Heat Pumps & Air Conditioning: UK Heating and Cooling Q&A
Our latest Homeowners’ Q&A episode has just dropped...
By Mars , 3 days ago
-
RE: Vaillant ecoTEC Plus with sensoCOMFORT and weather compensation
Yes, its described in the sensocomfort manual. Its als...
By JamesPa , 3 days ago
Members Online
No online members at the moment








