Posted by: @togfather

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@toodles Thank you for this. I will give it a try 🙂

Although this is generally good advice, as @iancalderbank pointed out, you need to get the very low flow rate fixed first in order to get heat into your house.

@togfather the flow rate is crucial. If that stays at 10.7, you will never move enough heat, there is basic physics in the way, the rate of movement of the water is directly related to the rate of the heat movement, it needs to be 20-25l/m at least.

I don't know enough about daikin to know if there could be some setting causing it to be low. If you are able to turn off the backup heater, please see if that makes any difference to the flow rate, if not then something else may be required.

@toodles @chrislay can you help with where are the pump speed settings on a daikin?

regarding your installer and daikin

1. they are just plain wrong about weather comp costing money. the point of weather comp is that it reduces the heat pumps power in proportion to how warm it is outside (or increases it in proportion to how cold, if you like). The times when its mild spent running at lower power , saves you money.  (Bit more to it than that, but thats the "in a nutshell")

2. The low flow rate is a clear and obvious demonstrable fault with the system. There is no way they can "debate" whether its large enough. Its not, the system will never move enough heat to warm your house with this low flow rate. You can legitimately keep on calling them back, asking for your money back, until they get this value to where it should be.

@iancalderbank I have just looked in the Daikin Installer’s Manual and I am attaching a screen grab of the relevant part of a page about pump volume. I am confused to say the least! With my sight and having to magnify the image on my iPad, navigating the pages is very awkward. I will try to find HOW to adjust the flow rate but meanwhile, at the bottom of the image is the manual details so that Tog can look it up if not in possession of a printed copy.

Regards, Toodles.

Just found this link for the manual in case it helps you.  

https://www.daikin.co.uk/content/dam/document-library/Installer-reference-guide/heat/air-to-water-heat-pump-low-temperature/EHVH11-16SU28CB6W,%20ERHQ-BV3,%20ERLQ-CV3_4PEN449979-1_Installer%20reference%20guide_English.pdf&usg=AOvVaw3OcY6H5ivH90kEetHkPonT&opi=89978449Regards ," title="GOOGLE.COM" rel="nofollow" target="_blank" >

GOOGLE.COM "https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjVi5-qj_GDAxX_SEEAHVfYDi8QFnoECCAQAQ&url= https://www.daikin.co.uk/content/dam/document-library/Installer-reference-guide/heat/air-to-water-heat-pump-low-temperature/EHVH11-16SU28CB6W,%20ERHQ-BV3,%20ERLQ-CV3_4PEN449979-1_Installer%20reference%20guide_English.pdf&usg=AOvVaw3OcY6H5ivH90kEetHkPonT&opi=89978449Regards ,"

Toodles

I’ve done my best as my sight allows for now, may I suggest Togfather that you look at section 8 on configuration where you will find mention of the back up heater. My system doesn’t have such a heater and therefore, I don’t wish to rootle through the configuration which may not be the same anyway! I’m glad my installers set up my pump correctly, it sounds like your is a real nightmare job and the installer should be putting it right for you - compensation?

Regards, Toodles

@iancalderbank I don't know if you can set the actual pump speed. As far as I know the controller sets the speed to maintain the delta t. 10.7 is the minimum and the max is about 40. It will then switch the compressor on/off as well. I think the default dt is 7 or 8.

One other thought - did the installer upgrade any pipework? - oil may have been piped with 22mm - that will be too small.

@chrislay yes, the new radiators were installed with new pipework.

Tog 🙂