Ps large spike @ 1pm.ish is toaster being switched on for lunch. Either side of this is mostly heat pump consumption. You can see the difference before and after of the electric consumption. Much smoother after 1pm.when settings changed

Hi Andy, I would interested too in this as Ive just installed a 5kW Samsung Gen 6 with radiators and my delta T is actually 3 deg C. What does the setting actually change, do you know?

I cant help but notice your heat pump seems a tad big for your property? I had a 120 sqm 3 bed bungalow with a B EPC, UFH and thermal store and only had a 5kW Ecodan. Its insulation was excellent though as it was a timber frame filled with Kingspan. Did it come with the house? Is there a heat loss calculation?

Ps large spike @ 1pm.ish is toaster being switched on for lunch. Either side of this is mostly heat pump consumption. You can see the difference before and after of the electric consumption. Much smoother after 1pm.when settings changed

@bontwoody the heat pump came with the house from new. How on earth do you confirm if it's been oversized, Do I have anyway of rectifying this with the developer? One issue maybe the high ceilings upstairs. This upstairs space is  8m X 7m 3.2m high ( open plan room) with 4 sets of windows effectively in the same space one of which I'd  and large box window.

To be honest as it has a digital inverter is it so important about the sizing? Obviously with a fixed compressor this is critical? Only asking as I've no real understanding. Inresting that your heat pump is delta T 3 design.

just to confirm: Settings originally Delta T 5oC changed to Detla T 3oC. As far as I can tell it changed the compressor, as the noise of the pump changed, like it shifted down a gear...

Posted by: @andymc

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I noticed that under 40**Heat setting you can set the 405* inverter pump (assume compressor) delta T to 3oC (originally set to industry standard of 5oc). I'm assuming compressor as the heat pump noise/compressor instantly dropped down once I had saved the new settings (plant room next door to external air source heat pump so you can easily monitor)

I just want to check if adjusting the delta T will cause any major issues for the heat pump?

3 bedroom semi  (130sqm) new build property, excellent insulation roof, floor and walls (EPC B soon to be A with solar panels). Underfloor heating both upstairs and down (upside down living). Upstairs is open plan so floor is technically one huge radiator

Low temperature set for flow temperatures (3Oc/43c @ 12/-2)

Once I changed delta T, the actual electricity consumed did drop and it's smoothed the operational watts/kWh used (down from 1.7kwh to 1.5kwh as shown on the heat pump instantaneous usage) today temp @6.4 when changing settings. Obviously flow temperature went up but no increase in energy consumption, if anything dropped down.

Basically turning down the delta T has smoothed the energy consumption and slightly lowered the khw instantaneous use. Warmer floor/house due the slight 2 degree increase of flow temperature. I certainly would not recommend this for any other household. More concerned if reducing the delta T of the inverter pump will this cause any major issues?

Very limited information about this topic (if any) gen 6 inverter Delta T on the web. Indeed it's stunning the variation of the recommend settings for the Gen 6 Samsung heat pump. Feel sorry for installers as the recommend settings vary widely from one organisation to the next (underfloor heating flow quoted as: 35/40 @ 15/2 or 25/40 15/-10  or 30/45 13/-2 take your pick). Original setting of 35/40. 

Have to thank Graham for his video and guidance about Samsung weather compensation settings. Strangely turning the flow temperature down from 35 to 30 actually made the floor feel warmer....unless of course I'm imagining things... certainly no difference to comfort levels but reduced KWH used.

The heat pump does seem to short cycle when it gets close to design temp of 13/30oC However being digital inverter driven I'm assuming this is not a huge issue?

 

 

The DeltaT will relate to the temperature difference between the LWT and the RWT. I can't say for definite, since I cannot see or hear what is happening, but the DT value is often used to control the speed of the water pump. Dependent upon how the system is operating, this may have a knock on effect to the compressor speed.

The compressor speed is normally varied to produce the required LWT as calculated from the WC settings. The water pump speed can be varied to produce the desired DeltaT, which helps dictate the quantity of heat energy being supplied to, and being absorbed by, the heat emitters.

There are no hard and fast rules when it comes to the Weather Compensation (WC) settings, since they need to be adjusted to the heat loss characteristics of your home.

Derek, so if the pump is at a fixed speed, WC has been set 30-40 (both before and after delta T change),

delta T reduced from 5 to 3, then the flow temperature would increase (as it did)?

Posted by: @andymc

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@bontwoody the heat pump came with the house from new. How on earth do you confirm if it's been oversized, Do I have anyway of rectifying this with the developer? One issue maybe the high ceilings upstairs. This upstairs space is  8m X 7m 3.2m high ( open plan room) with 4 sets of windows effectively in the same space one of which I'd  and large box window.

To be honest as it has a digital inverter is it so important about the sizing? Obviously with a fixed compressor this is critical? Only asking as I've no real understanding. Inresting that your heat pump is delta T 3 design.

Well as a guess I suppose you could measure how much power it was drawing during a very cold snap, multiple that by its current COP and that might give an indication of how much power it required as a maximum? Im no engineer but I used to look at mine in my old house and noticed it was drawing about 1.2 kW when heating the house and 1.6 kW when heating water up to about 52C. It seemed pretty sensible to me that its COP was about 4 when heating and 3 when doing DHW which hit the 5kW button pretty well. Of course someone with more knowledge might well come and debunk all the nonsense I just spouted 🙂

You would hope that a heat loss calculation was done when it was fitted, maybe the developer has it if its not in the sale pack?

You may well be right about the digital inverter and perhaps if the heat pump is oversized you just pay excess for the installation and it has little or no effect on the running costs.

As for my setup, its a self install and I cant claim I designed it for a delta T 3 🙂 It just has one. I took the existing rad system, and ripped out the microbore for 15mm plastic and upped the radiator sizes. Its worked surprisingly well so far at 1 week in. It wasnt quite so much of a shot in the dark as it sounds as I ran the gas combi at 40C first to see how it coped.

Im not sure I follow the discussion on the change to setting 405*, wouldnt an increase in flow temperature tend to increase delta T as the heat gradient is higher?

Posted by: @andymc

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Derek, so if the pump is at a fixed speed, WC has been set 30-40 (both before and after delta T change),

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delta T reduced from 5 to 3, then the flow temperature would increase (as it did)?

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Was it the LWT that increased or the RWT?

I only checked the leaving water temperature (from Samsung display). When it runs again tomorrow I'll have a look at the difference between the 2.

Interestingly kWh/watt consumption dropped when flow temperature went up.... I'm assuming when I check tomorrow I should only see 3oC temp difference bet LWT and RWT?

@derek-m the LWT is 32 whilst the return is 29 ( 1 Deg difference from original delta T5). As the additional 1oC is on the return  (originally 5) I'm assuming we have gained an extra 1oC..?

As mentioned we have underfloor heating throughout the house. So I'm assuming the whole floor area (less plasterboard  internal walls ) is one huge emitter?

Would the lower delta T be an issue for the heat pump? Is their any benefit to having a lower delta T. I'm assuming not as the floor is acting as one large emitter?