Posted by: @lfranklin

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I have a 12kW Samsung ASHP with Hive thermostat that my installers (Greener Living) don't seem to be able to make work consistently or economically.

The whole system is installed into the loft with the thermostat down in the L shape living/dining room. about 2 weeks ago the bedroom it sits over can hear what i think is the expansion vessel working and its very annoying when trying to sleep! - wasn't that loud until then so not sure why it is loud all of a sudden)

It's been installed since end of December now and i'm struggling with it not heating up last two rads on the system (which are downstairs in the living/dining room). They have added a second pump onto the return side of the system and that seemed to help for a few hours when first installed but now not coming back on again. if i turn the TRV off on others earlier in the system off the last two do get warm but even then not hot)

so the system is taking a lot of kWh to run to get the living room up to temp and then the temp is dropping quickly once it reaches 18 degrees as not enough ambient heat from the working radiators on the system.

i have had to take to turning thermostat down as couldn't afford the £15 per day electricity bill it was generating.

We had solar installed at the time too (16 x 405w panels) and even that isn't working right at just 1-1.8kwh per day generation at the moment which seems extremely poor for this size of system that works on PV and min 7 hours daylight at the moment.

All in all feel at my wits end with it all

To my knowledge, expansion vessels don't normally get reported to the noise abatement society, can you describe the noise? If it is a gurgling or tinkling type of sound then it could indicate air in your system.

If the thermostat in your living room is, as I suspect, the Hive, then ask Greener Living to install the Samsung controller in a more appropriate location than your loft. How accessible is your loft?

To be able to correctly adjust the WC parameters it will require access to the Samsung controller.

You should also ask Greener Living to correctly balance your radiators so that they are heating all the rooms evenly.

@derek-m my loft isn't too bad at all to access as have a pull down ladder so not too bad for occasional visits to tweak system as needed 

The noise sounds like a traditional boiler when first switched on an building up pressure. Not something you want coming through the ceiling of your bedroom every hour whilst trying to sleep.

It seems the skill of balancing rads has been lost on the younger generation of plumbers in GL employ.

Posted by: @lfranklin

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@derek-m my loft isn't too bad at all to access as have a pull down ladder so not too bad for occasional visits to tweak system as needed 

The noise sounds like a traditional boiler when first switched on an building up pressure. Not something you want coming through the ceiling of your bedroom every hour whilst trying to sleep.

It seems the skill of balancing rads has been lost on the younger generation of plumbers in GL employ.

Call me an old cynic, but I am rapidly becoming suspicious of companies with 'green' or 'greener' in their name, since I suspect they have merely jumped on the renewable bandwagon, what happened to 'Jones & Sons Heating Engineers since 1865'. But that does not resolve your problem.

How confident are you adjusting controller settings and possibly balancing radiators?

As far as the noise in your loft is concerned, switch your system to DHW heating, which should make your heat pump work a little harder, then go into the loft and see if you can identify the culprit. Where is your heat pump located, since they can be quite noisy when provoked.

I'm even more confused by the spikes now as we were out so heating has been off all day and for some reason it has still spiked?? Any ideas?

I went into the loft at as could hear the bloody thing running through bedroom ceiling and it was showing water pump and some other bits and a very high heat water temp on main front screen

. why is this happening (and so often) and how can I tweak settings to stop it?

@lfranklin A water temperature that high must be your domestic hot water legionella heating cycle. It needs to heat to this temperature to kill the legionella. Mine is set up to do this once per week, at 0300hrs on a Wednesday morning. Timing is adjustable and the manual should tell you how.

As to the other spikes, these do seem very frequent. Could be your water temperature is set too high in your weather compensation curve, setting it lower will make the heat pump more efficient and - by better matching your heat input with what the house is losing - should give you less frequent cycling.

I've experimented with different locations for my Hive thermostat until I found one that generated a relatively stable profile. I tried it once on the stairwell wall but it created such a lot of cycling (like your visual) that I moved it. I think it was close to an external wall section and this was no doubt the cause. 

@dunlorn hi the disinfectant thing is off since last week (I intend to do it once a month not once a week as it seems VERY energy hungry.

I think the compensation settings at the moment is 50° & 37° (or other way around.. can't remember off top of my head)

The room thermostat has been set low today and has not caused the heating to kick in at all today (checked the hive graph) so this seems to just be the hot water for the tank not the heating.

Posted by: @lfranklin

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a very high heat water temp on main front screen

That is your flow temperature, and seems quite high.  The  legionella heating cycle should only be once per week (or as you set it, mine is set to once per week).  This cycle does not use the heat pump afaik.  I have the 16kW Samsung, here is my legionella cycle, notice no change in the flow temperature.

My hotwater is set to 55, here is a "charge cycle" using the heat pump.

@lfranklin My installer left mine with settings of 50° at 2° outside, and 42° at 15° outside. I've deliberately let them be for a while as I get to understand the system. The reality is these are too high. I'm about to change and experiment at 45°@-2 and 35°@12. Ours is an old stone house, with suspended floors so not the best insulation. 

PS if your Hive set up is the same as mine it only controls heating. Domestic hot water is controlled by the Samsung controller.

PPS I also keep mine running if out for the day. It'll depend on your house but mine takes an age to get back to a comfortable temperature inside when it's this cold outside. Even dropping it to 16 at night can mean it takes hours to get to 18 (thermostat set point) in a morning. 

Not sure any of that is helping..... 

@dunlorn our home exactly same (1860 stone semi solid wall & suspended floor downstairs)

I turned the heating off purely to see what was happening with the spikes without the heating in play as was convinced it wasn't heating itself doing it... Which I have now done so now just have to figure out how to stop it.

😊

@lfranklin Sorry, I've been scratching my head wondering how, if your heating is off, you are getting such cycling. Doesn't sound right to me but I'd be speculating if I was to venture an opinion. I think you're doing the right thing to closely monitor and just change one thing at a time to see what happens. 

Hopefully you'll get some wise words from someone here and if you manage to get anything from your installer (good luck!) please let us know. 

Posted by: @lfranklin

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to see what was happening with the spikes without the heating in play

Your charts are only measuring electricity, how do you know how much of that is going to your heat pump?

The timing of the spikes suggest a DHW recharge in the evening, after each shower/bath.  That is what happens in my house. 

In my house, there is a recharge early afternoon, on a schedule, then one after each person has showered.  It looks like that is what you are seeing.

@william1066 yes makes sense if we had been doing that 

the heating was off all day and we had no showers/baths as were out.

Also I watch my app a lot and know when my hive heating for example says it's over target temp so if spiking when heating a few ° over thermostat set point its not the heating.