Ecodan ASHP cycling...
 
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Ecodan ASHP cycling every couple of hours

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(@crustydoodle)
Eminent Member Member
114 kWhs
Joined: 9 months ago
Posts: 19
Topic starter  

Hi all,  I am a noob here so hopefully posting in the right place.

We have recently had the following installed:

  • Mistubishi Ecodan R32 11.2kW
  • Mitsubishi FTC6 controller
  • Underfloor heating throughout (Heatmiser controlled)
  • The Mitsubishi cylinder is horizontally mounted in the loft as shown in the picture.

We are seeing a behaviour which our installer said should not happen and yet Mitsubishi claim is 'normal'.  Every 2-4 hours, the ASHP will activate when there is no call for hot water or heating (and no legionnella cycle).  The Hot water calls appear to be normal and happen as expected.  

We were told that the ASHP should only really come on at the moment when the hot water needs bringing back up to temp.  This is clearly not the case and now the installer is backtracking following a call to Mitsubishi.

I've complied a full day of hourly traces into one image (attached) that shows these spikes in the form of flow and return temperatures spiking, then gradually dropping and then triggering to spike again when it hits around 25degC.  On this trace you can also see a hot water call and the cylinder temp rising to the correct level.  We also tested the heating last night so you can see some activity around that.

We can also hear that water is being pumped through the services in the wall on the internal side of the setup - not sure if it is requesting water or wasting water or both, but it is coming from where the mains connects into the ASHP setup and where the ASHP connects down to the UFH manifolds.

As a side note, we did have an L9 error as well but this has not returned and so we think it is not related.

The main issue is that the pumps and water movement in the loft is noisy enough to wake us in the night. We are very tired!

I am not convinced this is normal behaviour - if it is, then we have a major issue with constant noise through the night.  The 2 other Ecodan users I know do not see this happening.

Any ideas or seen this behaviour before?  

Thanks in advance

IMG 2249

 

ASHP Hourly 210923

 


   
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Morgan
(@morgan)
Noble Member Member
4210 kWhs
Joined: 3 years ago
Posts: 542
 

@crustydoodle I cannot answer your question although I'm confident somebody will be along soon that can help.

Just to say I'm gob snacked at the horizontal install of the tank.  Never seen that before on any form of set up.  I stand to be corrected but I didn't it even possible never mind advisable.  Looks wrong to me.

Good luck.

Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.


   
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(@derek-m)
Illustrious Member Moderator
14051 kWhs
Veteran Expert
Joined: 3 years ago
Posts: 4210
 

Posted by: @crustydoodle

Hi all,  I am a noob here so hopefully posting in the right place.

We have recently had the following installed:

  • Mistubishi Ecodan R32 11.2kW
  • Mitsubishi FTC6 controller
  • Underfloor heating throughout (Heatmiser controlled)
  • The Mitsubishi cylinder is horizontally mounted in the loft as shown in the picture.

We are seeing a behaviour which our installer said should not happen and yet Mitsubishi claim is 'normal'.  Every 2-4 hours, the ASHP will activate when there is no call for hot water or heating (and no legionnella cycle).  The Hot water calls appear to be normal and happen as expected.  

We were told that the ASHP should only really come on at the moment when the hot water needs bringing back up to temp.  This is clearly not the case and now the installer is backtracking following a call to Mitsubishi.

I've complied a full day of hourly traces into one image (attached) that shows these spikes in the form of flow and return temperatures spiking, then gradually dropping and then triggering to spike again when it hits around 25degC.  On this trace you can also see a hot water call and the cylinder temp rising to the correct level.  We also tested the heating last night so you can see some activity around that.

We can also hear that water is being pumped through the services in the wall on the internal side of the setup - not sure if it is requesting water or wasting water or both, but it is coming from where the mains connects into the ASHP setup and where the ASHP connects down to the UFH manifolds.

As a side note, we did have an L9 error as well but this has not returned and so we think it is not related.

The main issue is that the pumps and water movement in the loft is noisy enough to wake us in the night. We are very tired!

I am not convinced this is normal behaviour - if it is, then we have a major issue with constant noise through the night.  The 2 other Ecodan users I know do not see this happening.

Any ideas or seen this behaviour before?  

Thanks in advance

IMG 2249

 

ASHP Hourly 210923

 

Noise in the pipework is possibly due to having air in the system. I would suggest bleeding any air out of the system.

I believe that the FTC6 controller may periodically run the water pump to get a more accurate water temperature measurement after which it may decide the water needs warming. How is your system set to operate, is it set for a fixed Leaving Water Temperature (LWT) or in Weather Compensation (WC) mode?

 


   
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(@crustydoodle)
Eminent Member Member
114 kWhs
Joined: 9 months ago
Posts: 19
Topic starter  

@morgan It's a special version designed for horizontal install.  Not worried about that bit!  I think it is this one, or similar.

https://www.telford-group.com/product/horizontal


   
Morgan reacted
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(@crustydoodle)
Eminent Member Member
114 kWhs
Joined: 9 months ago
Posts: 19
Topic starter  

@derek-m Thanks for the reply - I am not sure how to check this.  It says in the settings it is Z1Mode HHC. Does that answer it? 

We have no rads and all the bleeds on the HW cylinder have been opened.

This post was modified 9 months ago 2 times by Crustydoodle

   
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(@derek-m)
Illustrious Member Moderator
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Joined: 3 years ago
Posts: 4210
 

@crustydoodle

Please describe the noise that you hear.


   
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(@crustydoodle)
Eminent Member Member
114 kWhs
Joined: 9 months ago
Posts: 19
Topic starter  

@derek-m Here's some videos that have the sound in it.  Having to send links rather than attachments as the forum won't take mov files.  The internal one is more what we hear, but somehow amplified through the ceiling.  

Also this external one, which I captured just after the ASHP stopped running, gives an indication of the noise from outside. (There is a little more lagging still to do!)

Apologies for the handycam work!


   
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(@derek-m)
Illustrious Member Moderator
14051 kWhs
Veteran Expert
Joined: 3 years ago
Posts: 4210
 

@crustydoodle

I'm afraid that i'm getting an error message when I try to play the video. Would you describe the noise as a tinkling or whooshing sound? 


   
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Morgan
(@morgan)
Noble Member Member
4210 kWhs
Joined: 3 years ago
Posts: 542
 

Posted by: @crustydoodle

@morgan It's a special version designed for horizontal install.  Not worried about that bit!  I think it is this one, or similar.

https://www.telford-group.com/product/horizontal

Every day's a school day.

 

Retrofitted 11.2kw Mitsubishi Ecodan to new radiators commissioned November 2021.


   
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(@crustydoodle)
Eminent Member Member
114 kWhs
Joined: 9 months ago
Posts: 19
Topic starter  

@derek-m It's more of a gentle whoosh or constant mechanical hum.  We had some strong vortex-y whooshing early on when something wasn't set up right.  This sounds very much like if you stand next to the mains inlet to the house when a tap is running, if that makes sense.


   
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(@derek-m)
Illustrious Member Moderator
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Veteran Expert
Joined: 3 years ago
Posts: 4210
 

@crustydoodle

Noise from pipework could be due to vibration of the physical pipes. Whooshing is normally a sign that the flow rate is too high or there is some form of restriction. What does your installer say may be the cause?


   
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(@crustydoodle)
Eminent Member Member
114 kWhs
Joined: 9 months ago
Posts: 19
Topic starter  

@derek-m Well, that is the interesting bit.  They have not seen this behaviour, they came for many hours last week, though they had resolved it and, as they were leaving the house the ASHP came on when it shouldn't.  After spending a good hour or so on the phone to Mitsubishi, Mitsubishi themselves are claiming this is normal behaviour.  I do not buy it so am asking for proof, explanations why and how we can change the behaviour.  The installer is currently repeating the Mitsubishi message.


   
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