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

@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? 

@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

@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.

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 

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

Posted by: @gary

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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? 

Posted by: @gary

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@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?  

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

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

Posted by: @gary

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@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.