Best flow settings for Daikon heat pump (ASHP) with Dimplex Smart Rads

Hi that’s very interesting. Before I try anything can you please tell me I am correct in my thinking. I am reading LWT Main as the LW temp, which is set at 48. When I look at the sensor when the rads are convecting it gets up to a temp of around 40. So to lower the LWT then I just reduce this setting from 48 to say 40 or 35. I was told by Dimplex that the rads need a temp of 35 before they start convection, so would an LWT of 35 maybe to low? I guess it’s a case of trial and error. My query is that if a LW temp Of 48 is not sending warm enough water to those two rads, how would a lower LW temp work?

thanks

I have a different heat pump so I'm not sure how to reduce the flow temp on yours. 35 would be too low as you lose some heat in the pipes. 40 is worth trying.

My thought on a using a lower flow temp is to gradually bring your house up to temperature, rather than doing it quickly using a high flow temp. Initially it will still be slow to heat those two rads but once the house is warm they will work fine. Just don't play around with the house temperature and don't let it drop too much. You can't treat it like a gas boiler.

To answer a couple of your other questions:

Look at https://www.heatgeek.com/  - they have lots of videos about running a heat pump and getting the most out of it. A lot is technical stuff for installers, but there’s advice for homeowners too. If you’re lucky there’ll be one in your area who might be able to check over your system. They have a map at https://www.heatgeek.com/find-a-heat-geek/

My Daikin controller has this display which shows, amongst other things, the temperatures of the water which flows through the radiators.

Leaving Water is what leaves the heat pump (also called flow in plumbing terms) so 37 deg in this case.

Inlet Water is the same water, now cooler, returning to the heat pump to be reheated (called return in plumbing terms). 

PHE is the Plate Heat Exchanger (don’t ask!).

If your controller is like this let me know and I can tell you how to alter the LWT, though it sounds more like @hydrosam has the same one as you.

Yes just the same 

Juliamc 

who are HeatGeeks? What makes them different from other installers please?

My brain has been pondering your problems overnight. Do you have isolation valves on the pipes to the radiators? I don't know if this is recommended but you could limit the flow to the rads at the start of the circuit by partially closing the isolation valves.

The other thing you could try is bleeding the rads. I think the instructions for this are in the manual.

Hi

the installers added butterfly valves to several of the rads a few years back to try what you suggest. It is such a faff to try how open or closed each valve needs to be for best effect. Also I can’t get my head around how slowing the flow down will help? Won’t this even take longer for the flow to the end rads reach the desired temp to set them off?

I have tried bleeding but when I loosing the screws only water drips out and I am not sure if this means there is no air in the system??

Enthusiasm. Training. Attention to detail. They won’t just sling in a heat pump and leave the customer to work out how to get the best out of it. There are installers who are just as good but a HeatGeek badge makes them easy to spot!!

Great thanks 

Mon the map there are different colours, do you know what they mean? We have one in Elgin which is nearest. If I call him should I mention Heat Geeks. Cheers again

On their website it shows the various levels of training courses they’ve completed. Yes def mention you found them via the HeatGeek website. Btw I don’t have any connection to them except I was lucky enough to get a top heat geek to check over my heat pump and advise my installer what needed doing to improve the performance.