Ecodan ASHP - How t...
 
Notifications
Clear all

Ecodan ASHP - How to optimise my set up?

70 Posts
12 Users
20 Likes
2,292 Views
(@jaket)
Eminent Member Member
114 kWhs
Joined: 3 months ago
Posts: 17
Topic starter  

Hi all, 

I've recently purchased a new build property that came with an Ecodan ASHP set up (details below). 

I have been reading / tinkering as much as possible, but given there is so much to learn I thought it would be best to ask a blanket question:

"Are there any suggestions for optimising my controls / settings, given my situation?"

Currently my COP averages around 2.2x, (Oct-23 to Jan-24), and to be frank - the overall consumption feels high

Yesterday heating alone consumed 30kwh, delivered 62kwh (outside temps were below 5c the entire day), I guess if the COP was above 3x, then the consumption would be easier to stomach. 

Right so details on my set-up: (see schematic diagram below)

  1. 100% electric house 
  2. Ecodan 6kW - PUZ-WM60VAA
  3. 283L Tank 
  4. The roof has Solar PV (tiny 0.4kw) and Solar Thermal 
  5. The property is a Semi-detached 3 story, 4 bedroom
    1. Zone 2 - (ground floor) - UFH (there are two Heatmiser room stats, 1x kitchen + 1x living room - all set to 18c) (I think the heatmisers are linked to the UFH manifold? See picture below) 
    2. Zone 1 - (1st + 2nd floor) - rads (one Heatmiser stat located on the 1st floor - set to 17c) (all Rads set to fully open) 
    3. Total floor space = 119m^2
    4. Total property volume = 319m^3
    5. EPC = A (92), with "very good insulation" 
    6. Air permeability = 5.55 (
    7. Currently two people living in the property (one who loves opening the trickle vents, and one who loves closing them. 🤣 )
  6. Current settings:
    1. DHW Target Temp = 45c 
    2. Weather compensation curve set to -10c = 43c & 20c = 25C (no idea if this is anywhere good??) 
    3. Flow rate 9l/m (this was set at 3 in the Ecodan module, but there is also a Grundfos pump set to1? (see schematic diagram below)
    4. We don't have set back temps / timers
  7. A couple of observations so far: 
    1. When we moved in all stats were set to 21c, the house was very warm and was consuming c. 55kwh a day for heating (outside temp c. 12c), we moved the stats down (although I am not sure if we shouldn't have just adjusted the weather compensation curve instead?)  
    2. The hot water temp when taking a shower drops rapidly, like after three minutes even if I max out the mixer I can feel the temp dropping. (rain shower head, so consumption may be high?) 
    3. The Ecodan seems to short cycle quite a bit (heatmisers are always switching between calling for heat / not calling for heat), this has gotten better since I flattened out the weather compensation curve. (see below pic of when it goes crazy) 

 

 

Any suggestions / comments on how to improve the COP of my set up? 😀  

 

image
1
2
3
5
4
8
6

 


   
Quote
Topic Tags
(@bontwoody)
Prominent Member Contributor
2681 kWhs
Joined: 2 years ago
Posts: 382
 

Hi Jake

My previous house had very similar stats to yours and had a 5kW Ecodan. I would suggest that yours should be very easy to heat at a low cost in the same way mine was. Your weather compensation curve is reasonable but your COP is awful. Looking at your setup the thing that jumps out at me is the zoning and heatmiser stats. I think these may be the reason why your flow temperature is all over the place suggesting a lot of stopping and starting.

I dont have a great deal of experience with these but my understanding is both should be avoided if possible. Extrapolating from my current system I would guess that you should set your stats high and try and adjust room temperature by affecting flow. On rads this is done by adjusting the manual valves leaving any thermostatic valves fully open.

Im sure others will be able to give you more specific advice but Im confident that you should be able to arrive at a good efficient system given time 🙂

House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60


   
Mars reacted
ReplyQuote
(@jaket)
Eminent Member Member
114 kWhs
Joined: 3 months ago
Posts: 17
Topic starter  

@bontwoody Thanks for the reply!

Yes, I had wondered whether if I should just crank up the heatmisers, to make sure they are not the limiters, and adjust adjust the weather compensation if it's too warm / cold. It is just baffling to me that an installation done from scratch, in 2023, would include what appears to be a completely redundant / obstructive layer of equipment (and have multiple of them). Does anyone know in what scenario it make sense to have the heatmisers? Or is there consensus that zoning and heatmiser stats when connected to an AHSP is a bit daft? 


   
ReplyQuote
(@bontwoody)
Prominent Member Contributor
2681 kWhs
Joined: 2 years ago
Posts: 382
 

@jaket Welcome to the world of bodged installations Jake! You are absolutely correct in your thinking. Having given it a bit of thought, I would try the following

1. crank up your heatmisers to 23C

2. maximise the flow through the rad? in the room you want warmest

3. run the heating for 4 or more hours to get it up to temperature

4. if your main room is too warm adjust your weather compensation curve downwards and vice versa

5. when you have your main room right, adjust the flows to the other rooms using the manual valve on the rads, keep any thermostatic valves wide open.

6. keep tweaking until you have all the rooms as you want them

7. im not sure how you would tackle the UFH. presumably it wont have a thermostatic valve fitted (it shouldnt)

 

let me know how its goes 🙂

House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60


   
ReplyQuote
 Gary
(@gary)
Estimable Member Member
856 kWhs
Joined: 1 year ago
Posts: 104
 

@jaket Hi I have an ecodan with ufh and rads and Heatmisers.  You can get it working well.  It will just take some tweaking.

What you will probably find is that you need to set the Heatmisers to limit the max temp. You said 21 was too hot so maybe that’s your max limit or 20.5.

From the hourly flow temps you posted your unit is cycling 4 times an hour this won’t be good for efficiency.

Ecodans don’t modulate down well so you find that flow temps in the 20’s will lead to cycling.  I have found that the lowest flow temp I can go to is 32C then regardless of the outside temp it won’t cycle.  So my curve is flat at 32C down to 3C then it ramps up 1C per 1C till it gets to 45C at -10C.

You want all your circuits open rads and ufh at the same time to maximise the water volume are heating this will reduce cycling and increase efficiency.

 

with regards to the Hot water how long are you heating it for?  Mine is set to 48C and heats for 2 hours.  This is long enough to get the entire tank up to temp from cold.  I don’t reheat at all there is enough for 2 showers washing up and kids bath before the next nightly reheat.  Check what your hot water settings are if it’s reheating after a shower its reheat temp is probably set too high.  Will just take some trial and error do you need to reheat or will the tank last a full day or just reheat once in the evening.

In the recent cold snap I was using 30-40kwh a day for heating you should be able to beat that.


   
ReplyQuote
 Gary
(@gary)
Estimable Member Member
856 kWhs
Joined: 1 year ago
Posts: 104
 
IMG 0288

Here is my flow for an hour yesterday afternoon it ran like this all day.

just noticed you posted flow rate was that from the running information menu using code 540?  If so it’s very low turn the pump speed up to 4 and 5 and see what values you get.  This will also be causing cycling and poor efficiency 


   
ReplyQuote



(@jaket)
Eminent Member Member
114 kWhs
Joined: 3 months ago
Posts: 17
Topic starter  

@bontwoody Thanks I will give this set up a go and report back. 😀


   
ReplyQuote
(@jaket)
Eminent Member Member
114 kWhs
Joined: 3 months ago
Posts: 17
Topic starter  

Posted by: @gary

-- Attachment is not available --

Here is my flow for an hour yesterday afternoon it ran like this all day.

just noticed you posted flow rate was that from the running information menu using code 540?  If so it’s very low turn the pump speed up to 4 and 5 and see what values you get.  This will also be causing cycling and poor efficiency 

 

Yes, that was using code 540, with the pump speed set at 3. 

If I increase the pump speed to 5, the flow rate (using code 540) shows 19 - is this better / sufficient? 

Maybe asked a better way, what flow rate is ideal? 

 


   
ReplyQuote
(@jaket)
Eminent Member Member
114 kWhs
Joined: 3 months ago
Posts: 17
Topic starter  

Posted by: @gary

@jaket Hi I have an ecodan with ufh and rads and Heatmisers.  You can get it working well.  It will just take some tweaking.

What you will probably find is that you need to set the Heatmisers to limit the max temp. You said 21 was too hot so maybe that’s your max limit or 20.5.

From the hourly flow temps you posted your unit is cycling 4 times an hour this won’t be good for efficiency.

Ecodans don’t modulate down well so you find that flow temps in the 20’s will lead to cycling.  I have found that the lowest flow temp I can go to is 32C then regardless of the outside temp it won’t cycle.  So my curve is flat at 32C down to 3C then it ramps up 1C per 1C till it gets to 45C at -10C.

You want all your circuits open rads and ufh at the same time to maximise the water volume are heating this will reduce cycling and increase efficiency.

 

with regards to the Hot water how long are you heating it for?  Mine is set to 48C and heats for 2 hours.  This is long enough to get the entire tank up to temp from cold.  I don’t reheat at all there is enough for 2 showers washing up and kids bath before the next nightly reheat.  Check what your hot water settings are if it’s reheating after a shower its reheat temp is probably set too high.  Will just take some trial and error do you need to reheat or will the tank last a full day or just reheat once in the evening.

In the recent cold snap I was using 30-40kwh a day for heating you should be able to beat that.

 

On the hot water - I can literally feel the temp start to drop after 3 min of use. 

I can only assume it is being caused by either:

  1. The rain shower head is pushing serious volume, resulting in cold water mixing within 3 minutes of use, 
  2. The outlet pipe is connected to the bottom of the tank. 

I think I will have to do a bit more research on this point, might have to see if this has been a common issue for other ecodan users?  

9

 

 

 

 


   
ReplyQuote
 Gary
(@gary)
Estimable Member Member
856 kWhs
Joined: 1 year ago
Posts: 104
 

@jaket yes leave at 5 19 litres per min is fine mine runs at a similar rate


   
Mars and JakeT reacted
ReplyQuote
 Gary
(@gary)
Estimable Member Member
856 kWhs
Joined: 1 year ago
Posts: 104
 

@jaket I would increase the tank temp you are heating to, 45C is too low if your showers getting cold after a few mins


   
ReplyQuote
(@jaket)
Eminent Member Member
114 kWhs
Joined: 3 months ago
Posts: 17
Topic starter  

Posted by: @gary

@jaket I would increase the tank temp you are heating to, 45C is too low if your showers getting cold after a few mins

I will give this a go as well. 

 


   
ReplyQuote



Page 1 / 6
Share:

Join Us!

Latest Posts

x  Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
Shield Security