Posted by: @drei

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Every winter go there, then come back, no need for a central heating system at all:

That was actually very popular with pensioners for a while.  Are you a pensioner?  Birds and other animals do of course migrate, but many humans consider nomads (also called travellers) somehow wrong.  Are they?

@temperature_gradient 

And then there's the running costs, where the benefit of the heat-pump's hugely better efficiency is entirely absorbed by the higher cost of electricity in Britain.

That's not necessarily true at all. 

I have now owned my Daikin 6kw for almost a year. It was installed (very well) by Octopus Energy. I have no solar nor batteries. My insulation is patchy.  My tariff is now a fixed rate deal with Fuse for 0.21 per Kwh + standing charge. 

I have spent less on whole house energy bills - electric only - than the year before - gas & electricity. I like a warm house, I work from home, I run it on weather comp without a thermostat to keep my house @ 22° during the day. It's super efficient. 

So even with my region's lairy standing charge & our stupidly high electric costs, it's a better deal.

But.... I concede, with the help of people in this forum, I geeked out on heat pumps before it was fitted, made sure I had good radiator acreage and struck lucky with an amazing team of Octopus fitters. These things help. 

@jamespa Others work such that you can only program setbacks  (or set forwards) by bouncing off an on/off sensor/thermostat the rest of the time, or using some home grown kludge.

There's a world of difference between using thermostats and dumping them. I prefer the latter - then there's no conflict between the heat pump and some bossy piece of thermostat kit on a wall somewhere.  Thus no 'bouncing', never any on/offs, just a heat pump with very clever internal design running things. 

The Daikin has very good controls in its MMI controller. The app is crap. If I run my Daikin via Leaving Water Temp control (pure weather compensation) there's no on/offs ever. It just ticks along 24/7. 

If I want to vary the leaving water temp via the curve I can just programme +/- the overshoot by 1° and it tweaks the curve accordingly for those specific hours but you wouldn't know - it's silent nothing goes on or off.  There's no 'home grown kludge' as you call it. No third party kit at all. 

It's impressive how those little algorithms quietly do their thing. 

Posted by: @lucia

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@jamespa Others work such that you can only program setbacks  (or set forwards) by bouncing off an on/off sensor/thermostat the rest of the time, or using some home grown kludge.

There's a world of difference between using thermostats and dumping them. I prefer the latter - then there's no conflict between the heat pump and some bossy piece of thermostat kit on a wall somewhere.  Thus no 'bouncing', never any on/offs, just a heat pump with very clever internal design running things. 

The Daikin has very good controls in its MMI controller. The app is crap. If I run my Daikin via Leaving Water Temp control (pure weather compensation) there's no on/offs ever. It just ticks along 24/7. 

If I want to vary the leaving water temp via the curve I can just programme +/- the overshoot by 1° and it tweaks the curve accordingly for those specific hours but you wouldn't know - it's silent nothing goes on or off.  There's no 'home grown kludge' as you call it. No third party kit at all. 

It's impressive how those little algorithms quietly do their thing. 

I completely agree. 

The extent to which heat pump controllers allow you to do this and at the same time do things like set back/set forward seems to vary quite significantly.  Daikin, as you say, and also Vaillant which I have, (doubtless there are others) being in the more flexible group, and others being less flexible. 

I had a discussion with the Samsung rep at the last installer show (Samsung appears to have one of the crudest UIs in this regard and I told the rep so!).  He was proudly demonstrating the latest colour UI and I asked him is it possible yet to program a set back/set forward without bouncing off the thermostat.  After some attempt to side step the question, he had to admit it wasn't.  His colleague then told me that the underlying logic to the UI hadn't changed, its just that the graphics were more fancy.  Some progress!

@drei Based on your recent posts, I am wondering what your original motivation was for a heat pump.  I do understand you have had a poor experience (which hopefully will get fixed), but setting this aside why did you go down the route in the first place?

This isn't a trick question, its a serious one because either you were mis-sold (which helps frame the situation) or it should be possible to achieve whatever objective you set out to achieve and thus make you happier.

Perhaps you could cast your mind back and let us know?

Posted by: @jamespa

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@drei Based on your recent posts, I am wondering what your original motivation was for a heat pump.  I do understand you have had a poor experience (which hopefully will get fixed), but setting this aside why did you go down the route in the first place?

This isn't a trick question, its a serious one because either you were mis-sold (which helps frame the situation) or it should be possible to achieve whatever objective you set out to achieve and thus make you happier.

Perhaps you could cast your mind back and let us know?

Blunt answer? The 20-year-old gas system was failing, and I had two choices: spend 60% less on a new gas boiler system (we were planning to upgrade the radiators anyway), or take the plunge with a heat pump.

Szymon’s Urban Plumber videos and Heat Geek’s content convinced me. Who wouldn’t want a system that promises the same heat as a gas boiler at a fraction of the running cost, and is “green” too?

That’s why I’m so furious and gutted at this whole experience. Every single person I told (builders, plumbers, electricians, solar installers, friends and even family) warned me not to do it. They all said I’d regret it, that I’d be cold, and that I’d bankrupt myself running the thing. I wanted nothing more than to prove them wrong. They even called me a pioneer — “testing new technology.” And yet here I am, two years later, still with no light at the end of the tunnel. Worst part? My wife told me I’d regret it… and she was right. That’s a bitter pill to swallow.

I don’t want other people to end up in the same situation, because the reality is you have zero guarantee that your system will deliver what you think it will.

I’m still trying to get ours sorted. Maybe one day I’ll be able to post here and say: “It took a hell of a journey and a hell of an effort, but I got it fixed, and now it’s costing me £150 a month instead of £500+.” That’s the hope.

But the bottom line is this: even after remedial work, my system will never be greener than a gas boiler. Maybe in 20 years, if it never breaks down, it might balance out. But the fact that I will have to throw away 80% of it already (new hardware) and replace parts is a huge waste, financially and in terms of carbon footprint. If I could do it again, I’d buy the best gas boiler I could find, run it like a heat pump, maybe add a couple of log burners for the winter, and I’d be warmer, wealthier, and less stressed.

@drei I will say again that Im sorry to heat about your woes.  Despite the fact that my heat pump install has been a sparkling success, Im angry too, albeit for a slightly different reason.  

Posted by: @drei

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But the bottom line is this: even after remedial work, my system will never be greener than a gas boiler.

I think the one thing you can be certain of is that this is no where near true.  I provided the numbers above to prove this.   Even if you replace the whole thing you would still be in 'carbon' credit after three or four years.  

Ive been on this forum (and another one) for 3 years now.  I have a degree in physics and a background in engineering and local government.  So I consider myself reasonably well placed to understand these things.  What the past 3 years (and my personal heat pump journey) has taught me (and the reason I am angry) is:

1. Heat pumps DO work, and they work very well, but only if the system is designed,  installed and used correctly.  There are plenty of happy heat pump owners around, probably the vast majority, but of course we mostly hear about the failures because, (a) if it works, people get on with their lives and (b) its in the interests of the oil industry to paint them as failures, and the oil industry has lots of money (and lots of influential friends) to amplify what it wants to amplify.

2. If done properly heat pumps will generally result in a greater comfort level, because low temperature heating is inherently more comfortable.  Of course this could be done also with a boiler, but we dont, and if we did then the cost of a replacement boiler system would be nearly as much as replacing a boiler with a heat pump so there is little incentive.

3. Heat pumps may save some running costs relative to gas/oil, particularly if you are smart with your choice of tarrif and/or have UFH.  But the savings are perhaps 20% at most with radiators (more with UFH) and if designed/installed badly they are just as likely to cost the same or more to run.  The exception of course is if the heat pump replaces resistance electric, where the saving is guaranteed.  Sales based on saving lots of money are, IMHO, mis-sales.

4. Its clear that a proportion of systems are not designed and installed correctly, usually for very simple reasons that are inexcusable.

5. Its equally clear that there is no effective recourse within the industry itself if your system is one of those.  In particular MCS is essentially useless from the consumer point of view despite the fact that they tell us they are there as a mark of quality 

I'm angry because the both the industry (through its lack of quality control) and successive Governments but especially those in power between 2011 and 2020 (by ratcheting up the price ratio between electricity and gas from 2.5:1 to 4:1), have systematically undermined the case for the transition from the consumers viewpoint, and the oil industry is ruthlessly exploiting this by painting heat pumps as bad, which they most definitely aren't if the system is designed and installed correctly.

I wish I could start a campaign on this, because it seriously frustrates me that the opportunity is being squandered because of a combination of industry and government negligence.

In the mean time, if you are serious about getting yours to work, you may get lucky with Section 75 (I really hope you do) or you have to accept that some self help is the best help.  There is absolutely no need to rip out your entire system so far as I an see; some judicious rad swaps (which are cheap!), the removal of the buffer and some tweaking of the way it is operated will likely do the trick based on what you originally posted.  You may have to accept however, that the industry wont easily provide the solution.  Thats wrong, I know, but how it appears to be.  If you do accept that you may well find you feel better about things.

After our rather lengthy meander off piste, I thought I would return to topic and update you on progress.   The summary is that it is all going well with absolutely no drama. Obviously, it is still early days, but there is a bit of a chill in the air now.

I have settled on a hot water schedule of 1 hour per night on a tariff of about 7p per kWh.  This lasts us the whole day, including three showers between us.  I have set the Legionella cycle for early Sunday morning, as we often have people to Sunday lunch and hotter water helps with the greasy washing up.

Turning on the hot water recirculation loop effectively depletes the hot water supply as it mixes hot and warm water.  I have mitigated this by insulating the remaining recirculation pipes.  The loop is a great feature, when used sparingly.  I wish we had a simple button to turn it on and off.

The external temperature has varied between 12.5-18C averaging about 15C.  The room thermostat is set to a target of 20C.  The measured temperature has rippled gently between 19.6-20.9.  The high points occurred around midday, 2 hours after the heat pump was last on, so they must be due to cooking or solar gain.  The low point at 6:40 am was easily recovered by a 20 minute heating cycle.

The central heating has come on 6 times in the last 24 hours, all of them short cycles of less than an hour.  The outlet flow temperature climbed to the dizzy height of 27C against a weather compensated target of 25C.  The compressor then reduced its frequency and shut down.  

So it’s all calm and no sign of any storms.

@grahamf you appear to value your recirculating loop despite it reducing your overall water temperature. If you switch it off how long does it take for the water to run hot and is it lower flow?

If it still gives you something (even if slowly) then consider getting an electrician to control your pump with a timer. There are lots for immersion heaters that you can program for a weekly pattern.

Or a wifi connected version with a local button (do a quick search or your electrician might suggest one) switch on by phone too.

I really like doing the legionnaires cycle before a mega washing up session! I would never have thought of that.

@judith thanks for your suggestions.  Starting from cold with the hot tap fully open, it takes 50 seconds for the water to come through warm in the kitchen.  After 60 seconds it is hot.  The flow is fast, so that is probably about 10 litres.  

The hot water recirculation loop shares most of the same hot water pipe down from the loft.  Somewhere under the floor, the pipe splits and it loops back upstairs to return the water back into the bottom of the hot water tank.

The recirculation loop is controlled by the Grant Smart Controller.  It treats it similarly to any other circuit.  You can specify on/off in half hour time slots on each day of the week.  In addition, during on time slots, you can specify how long the loop cycle runs for (set to 1 minute at the moment) and the interval between cycles (set to 30 seconds).  

All it really needs is a boost function on the phone app or controller display.  There is a boost function for immediately heating the domestic hot water, but not for the recirculation.

It is interesting to see what our new Grant Aerona 290 15.5 kW heat pump is up to. 

Here is a snapshot from the Econet web site for the last 24 hours:  

The external temperature has varied between 12.4-14.5C (pink).  The weather compensated flow temperature (dark green) is set to 25-27C.  When the heat pump compressor comes on, it mostly runs at its minimum frequency of 15Hz.  As you can see from the sawtooth shape, the flow temperature (red) goes up to about 28C, and then the heat pump turns it off - presumably because it is above 25-27C.  

The Circuit 1 temperature of the only thermostat in the hall has varied between 19.1 and 20.2.  The heat pump has been on only about half the time, so the weather compensation curve is probably in about the right place.  Unfortunately, the heat pump won't go quite that low.  I am nudging the WC up slightly to try to get the average closer to 20C.

Maybe as the outside air temperature reduces, the heat pump will be able to output at 25-27C, but by then I will probably want it to be higher!  

Glynn Hudson seems to be getting similar behaviour on his Aerona 290 9kW system, but he seems to prefer a higher room temperature of 21-22C.  His flow temperature is correspondingly higher and the compressor is running continuously.  There are 3-4 one hour slots when the compressor stops, but I don't know if that is based on a schedule, or the heat pump controller's decision.

https://emoncms.org/app/view?name=MyHeatpump&readkey=82a1cb1cf5b17b6e9dd419edc6a17970

Click on D (Day) or W (Week) to show his equivalent performance.