Well after a quick run around, bled the rads again (should have done that after I found another leak yesterday mid balancing!). I have opened all the lock shields up a bit and reduced the noise. Looks like this a next weekend job (again!) but house is warm and consumption isn’t horrendous.

Regards

Si

@grantmethestrength Well done, you are making progress now, I can’t be sure but I suspect the pump is running faster (harder) than it might need to. The noise is probably being caused by the water flow which, if slowed a little may well reduce the noise to acceptable levels. You mention that you have all new pipework and radiators so the chances are the pipework has the recommended smooth gradual bends rather than cast right angle joints as they are often the areas causing the water to produce a lot of the noise.

If you have a manual or guide which gives you the flow rate requirement and the information about pump litres per minute, you may well find a lower speed will still keep the heat pump happy and not start generating flow errors. (Which I believe is one of the most common error messages from the controller in most systems!) Regards, Toodles.

Cheers @Toodles, the flow rate at the minute is roughly 25/26 l/min (such a rubbish gauge!) flow temp 36c, return 33c and the pump is belting out 4,300 rpm and power consumption is solid at 1,000w.

I will have t look at it again next weekend when I have time.

On another note that gauge is brand new and looks like it is 10 years old is this normal? I have been going around all the joints where there is verdigris and cleaning them up to see if there are any more leaks.

Regards

Si 

@grantmethestrength Even with my poor eyesight, my immediate reaction when I saw the photo before reading your text was that that guage looks as though it has been in service for a long time. A ‘new’ fitting should look like a shiny brass body and the scale clean and well defined. Yours is anything but new in my opinion. The speed of your pump tells me very little I’m afraid as other pumps I have used or come across tend to indicate litres per minute or in the case of my own secondary Wilo Pico pump, it is displayed in cubic metres per hour expressed as 0.1 to 10 as a digital readout. (Good for the grey cells no doubt!)

Our Daikin monobloc 8 kW pump runs at approx 15 litres per minute most of the time; occasionally, I have observed it running at a flow rate of 31 lpm! As we have an LLH, the primary circuit looks after itself as the Homely Smart Controller oversees everything but I have the Wilo secondary circuit pump running at 0.9 (15 litres per minute) The primary pump does not appear to make any noise within the airing cupboard (This is where the heat pump’s plumbing enters the house.) so we have very little audible noise from any part of the heating system.

One more thing, you may find you can lower the flow temperature further, you will know when you go too low as the comfort level you currently enjoy will suffer. Make small adjustments and wait to see how the overall temperature changes; you could start initially with a 2 degree drop though - suck it and see. Lowering the flow temperature might also slow the pump a little if the controller on your system works that way. Regards, Toodles.

Cheers @toodles  I suspect that some of this install is merely “new” to us! I am currently looking at building my own homely “clone” using Home Assistant. I did turn the WC down quite aggressively but when the wind picked up it was just that little bit too cold. As I said in another discussion thanks to you guys on here I have got very close to ideal very quickly and it is now just a matter of fine tuning to get the best out of the system so props to you all!

Regards

Si

@grantmethestrength Oh well, pump speed investigations then! Toodles.

Regarding noise, we run at fixed flow rates of between 24-26L/min (so similar to you), and have a new system with 22mm copper runs, branching off to 15mm into the rads. All traditional right-angled soldered fittings here, so no shallow curved bends, and I cannot tell if water is flowing or not. All rads are fully open on both lock shields and TRVs. Even if I touch the pipes, I cannot 'feel' flow, other than they are hot.

Maybe there is still air trapped in the pipes?

The reason I tried to balance the system is that I have no confidence in the install. I know you are meant to run the system as wide open as possible but i had a DT of about 1c across most rads so the heat was pretty much just going back to the HP. Any advice on the best way to set them up as i am at a loss!

On a happier note I have only gone and blooming well done it full remote control of the Aerona3 via Home Assistant over modbus!

I'm not convinced that it's necessary to have big temperature drops across radiators with a relatively low temperature heat pump system provided the heat pump is happy to top up the flow temperature without a lot of cycling. A whole radiator at the same temperature will emit more heat than a radiator that has a hot end and a cold end.

@johnr This what I find a bit confusing, I thought that if the temps are the same or a small DT then no heat is leaving the emitter it is just flushing through. Steep learning curve!

Regards

Si

Posted by: @grantmethestrength

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@johnr This what I find a bit confusing, I thought that if the temps are the same or a small DT then no heat is leaving the emitter it is just flushing through. Steep learning curve!

Regards

Si

If water is flowing through the radiators quickly then DT will be small for any given heat transferred to the room, and vice versa. 

The heat transferred to the room is determined by the difference between the average radiator temperature and the room temperature.  The DT will then be determined by the flow rate and the heat transferred.  

Since the average radiator temperature reduces as DT increases, you actually want DT as low as possible so you can run at the lowest possible flow temperature, and thus highest cop.  In practice you are limited in this endeavour by practical pump speeds/flow rates in the pipework.  Artificially restricting flow to increase DT is counterproductive.