Few heatpumps even surport automatic updating of their software, so little possible of improving software as the makers monitor reallife usage.
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That’s a point - I have TRVs everywhere - I assume they should be fully open (Octopus adjusted them to balance the system) perhaps save for the bedrooms, then?
It’s recommended that the loop is kept fully open (so no TRV intervention), for best efficiency of the system.
Using a TRV in a bedroom(s) to make it more comfortable when sleeping, whilst keeping the rest open, I think is a pragmatic approach. It might cost you a bit of efficiency but then that’s the tail wagging the dog. We have heating systems to keep us comfortable in our homes, not to get them to run at peak efficiency.
I think that’s maybe the counter-point to having a system auto-adjust to be most performant and you can see it with Octopuses’ approach to installs now. They are essentially designing at a very high flow temperature, which for the majority of people is going to keep their house warm and keep installation costs very low. It might feel bad to the people who frequent these forums as we’re all really here looking to get the most efficient system we can, but actually this approach will work for most people. For example, I can’t imagine my 70+ year-old folks wanting to spend any time adjusting WD curves.
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100% this.
I’ll open up all the TRVs tonight. Thanks all - this is a brilliant forum and thanks for not hating on a n00b!
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Very interesting discussion.
This post got rather long - apologies…
I was down to get a Daikin 9kW Heatpump.
All their calculations pointed that way… they were pretty stubborn - quoting MCS etc…
Lots of discussions with Octopus got them to reduce to an 8!
Glad I did having read all the oversizing issues the 9-16s have, and perhaps redflags from this forum and other forums about oversizing is getting through to them?
I have my own set up challenges regarding house specifics.
Steep learning curve.
9 year old build, UFH everywhere except an over garage loft room - I plan to install UFH there this summer.
The first winter was always going be a compromise regarding that room. It reaches 18 to 19°C when the main house sees 21 (wife likes 21.5 really).
Celotex in the walls and 40cm loft insulation.
All doors open in main house.
Towel rads open (they don’t really heat the bathrooms much as they have UFH).
TRV and lockshield open (for now) on the loft room.
I found the carpet and underlay with a tog of 2.3 just strangled this at lower ASHP flow temps.
Before we’d just blast the gas boiler on full to that room a bit extra!
We are going to tile the lounge this summer and have a low tog rug. Part of a small redesign project - not too do with the heat pump really.
For now I just removed the underlay - what a big difference that made!
Tog of around 1 now.
Tiles in the kitchen and hall have tog of 0.1!
So you see the problem. It’s incredible how the heat just gets trapped and doesn’t warm the room.
I never got the Polypipe design specs of the UFH…
Octopus put in the following in the MMI WDC
DT 5
Max flow temp 45
-5 & 21
I’ve found I was hitting the Madoka setting of 21°C way to easily. Off for long periods as the UFH takes ages to loose heat, but not so the rad room… that drops to 14 or 15…
Set the Madoka to 22 and reduced the flow temp on the curve until 34 to 35°C was the norm at around 0 to 2°C outside and enough to warm the house to 21 / 21.5°C.
Thus far the thing is on all the time’ish - a break for the scheduled hot water run 1pm to 2.30, that is to 48°C.
I only did that mid last week, so perhaps some more improvements are to come.
In the 2 weeks we’ve had it, I’m seeing a weekly COP of 3 4 and 3.6 after more tweaks.
It’s been pretty cold for here
Night time temps of -1 to -2, max day temps of around 5 or 6, sometimes lower.
I have tuned the UFH flows to get 21°C downstairs and 19 upstairs.
I was at first knocking scheduled temp back to 20, the system shuts off until 4am (Cosy tariff cheap period).
Then takes an age to climb back up…
Probably better to keep going all the time as 19°C is fine for us to sleep in.
Is that COP acceptable for Feb and it will rise once the weather warms up a bit?
I only have the Daikin MMI data to go on and what our Smart meter shows for Elec costs.
I’m probably not up for installing after market monitors and analysing plots. Not yet anyway🙂
Ball park is good enough for now.
The comfort level is much better than the boiler system with the Polypipe controller, a room stat in each room), a water pump per each UFH manifold and associated mixing valves…
For the last two days I reduced the flow temp to 32°C.
This gave a steady state of 21.3 to 21.6 all day. The Madoka never kicked in and switched off.
I also tried not decreasing the schedule temp during the night.
Presumably the above, and the lack of being off and a cold start at 4am is the reason overall COP went up to 4.5.
The heating is interrupted for hot water at 1pm to around 2.15, and again at 4pm until 7pm - not ideal, but that’s the Cosy tariff!
My thinking, I’ll save by not having the heat pump on at all then - might be right, might be wrong?
We’re pushing all clothes washing and dishwashing to the cheap Cosy times…
Bills look okay so far according to the smart meter.
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Yep I’m happy to adjust the wd curve, but there will be lots of folks, young as well as old who don’t want to. But there are lots of very technical things that are discussed on this site that are very interesting and sometimes perplexing but that I would never dream of attempting. Currently I am running my system 7/24, on weather comp . I aim for around 18 degrees downstairs and a little less upstairs. This sometimes gets boosted by solar gain ( let’s hear it for solar gain). I currently have an offset of -5 , which gets me to my desired temp. My curve is set to 40 at -2 , 25 at 18. The latter because people keep saying the Daikin doesn’t like it below 30 and certainly not at 25. I am assuming that once temperatures reach around 15, 16, it’ll be time to turn the heating off for the summer, I’m hoping around end March, maybe mid April.
Just a general query, when people are quoting cop, are you quoting overall ie heating and DHW or just heating. Whilst I have an overall cop of about 4.1 since install clearly my DHW is much lower. But my overall cop is helped because I don’t use much hot water. My heating cop is around 4.5 currently.
if you are going to mention cop its probably better to say CH, DHW and then a combined number so there is no confusion ,
I quoted all, both CH and HW together.
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This might be of interest.
Hot Water only
11 days of January use since the install - settings pretty much how Octopus left it.
To be fair they accidentally put the valve on backwards so the heat pump thought the house was the hot water tank for an evening and night.
We came down the next morning to 25°C house! Rather high consumption was refunded🙂
They fixed it next morning.
11 days into February on my settings and you can see the difference in energy usage!
We have it coming on once a day 13.00 to when ready. Making use of the low Cost tariff time.
I have a question, on the sensors menu below flow rate is ‘flow switch’, this is currently set to off. Does anyone know what it does and does being off sound right?
You may find that the “flow switch” is a report rather than a setting, simply indicating that the low flow sensor/trip has not activated.
…and Sarah, that sounds like I should take that as good news?
…err I think so (my comment was based on Samsung hardware, in which I haven’t seen my Flow Switch indicated as ‘on’ ever since commissioning was completed).
Thanks Sarah.
I have a new question. I haven’t really paid much attention to flow rate but reading various posts here I’m thinking I should. So 8kw altherma 3. Had a whole of host of issues and system was recently reconfigured removing the buffer and converting that to a volumiser. I notice that my flow rate is consistently between 6.9 and 7.1. Now it appears from posts here that that may be causing inefficiency ie not getting as much heat optimally as I could. So typically what would other altherma users be seeing as their flow rate and can it be adjusted , is there a setting or is it purely determined by the heat pump?
very normal, see our last ~12 hrs, 24l/min on initial heat up and DHW…for a system with no buffer tank ie just a volumizer and one pump in the Monoblock
I was getting around 7, and then saw this video:
Doing the maths, the output was under my heat loss so the house simply wasn’t getting warm when the outdoor temp dipped under about 4C or so.
Setting my pump speed to high sorted it, and I made this video for others: https://www.youtube.com/shorts/emv5hasynzM
I’m far from an expert - learning all the time by trial and error.
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Thats the point I was making, you want a variable flow rate (not fixed) that matches/modulates the DT, working on the premise of high heat output would narrow the DT and heat the room/house too quickly, cycles the HP, low and slow is best IMHO, let the HP do its thing on auto/unlimited pump speed.
if your house if not heating up i would look elsewhere for the main issue, I am sure others will help and offer some advice, this is a helpful forum
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