British Gas Heat Pump installations

oliver1951

MFB , when you said you have your thermostats set for 30degrees c , did you mean thermostats or your flow temp?

oliver1951

MFB , and on Facebook, I don’t use it.

MultiFuelBurner

oliver1951 said:

MFB , when you said you have your thermostats set for 30degrees c , did you mean thermostats or your flow temp?

Thermostats. My flow temp is set to 35oC no matter the weather 24/7

The reason I chose this is because this is the most efficient flow temp for my system as per all the available documentation.

So for example I do not starve any room of that 35oC heat and I also do not restrict areas such as the downstairs snug that gets to 23oC yesterday where as the vaulted ceiling kitchen dining area reached 21oC. I just let the house pump the 35oC water around and do it's job unrestricted upstairs and down. The heat pump isn't cycling excessively and has a constant draw on the power.

This is this year's experiment having had an aggressive weather compensation curve last year which I record on our spreadsheet along with the weather for that day. (The heat pump has turned me into an ASHP geek)

QrizB

oliver1951 said:

So at present I’m relying on an electric fire 2kw and an oil fired rad ...

I did look at going for an electric system, like Fischer. But when I explored that the pricing was incomprehensible, by which I mean it was sky high. For something that I would have thought should have been way cheaper. 

Fancy German heaters filled with magic clay will be no cheaper to run than your current electric fire, and (as you now know) will cost an arm and a leg to fit.

See the link in my signature for comparison of the running costs of storage heaters vs. direct electric heating.

oliver1951

Just an update and to see if there are other with British Gas instals. Had mine installed mid June 2024. It’s a Daikin altherma 3 8kw, with a mixergy cylinder and a hive controller. Hasn’t had much use until the last two weeks so trying to work out how to utilise it. But have got a problem with the hive controller, at least it is thought the problem is with the hive controller. That problem is that as soon as it drops a tiny bit below the target temp it fires up again and as soon as it’s passed it, it stops again and repeat, so I spotted I was getting multiple 2-3 minute cycles. NOT GOOD. So I am having to watch it like a hawk and as soon as it hits the target dial the temp back a few degrees to stop it from going off again. I’m trying to gauge ( whilst also waiting to try and get a permanent fix for the problem from BG/hive/Daikin) what temperature I should let it drop to before I restart to get an efficient next cycle. What I have noticed is that across the cycles I have run so far I have been getting a heating gain of around 0.5c per hour. I have also noticed, by looking at my smart meter info, that the first hour of a cycle is using about 1.7kwh v 1.4kwh for each subsequent period. And even though the gain in temp towards the end is significantly less, the power consumption hasn’t changed. If anyone has a view on these things please do respond.

matelodave

IMO the last thing you need with a heatpump is a hive controller. They really aren't suited to being run like a conventional boiler and will use far more energy when they are being short cycled as you describe.

They are much more suited to being run at a fairly constant low flow temperature controlled by a correctly configured weather compensation to match the homes heat loss than they are with the on/off control of an external thermostat.

Reed_Richards

A decent central heating controller will let you limit the number of cycles per hour, either explicitly or implicitly (by telling it you have a gas an oil boiler, for example).  I can't find anything to indicate that Hive will let you do that.  I think your best option is to ditch Hive in favour of an alternative.

matt_drummer

oliver1951 said:

Just an update and to see if there are other with British Gas instals. Had mine installed mid June 2024. It’s a Daikin altherma 3 8kw, with a mixergy cylinder and a hive controller. Hasn’t had much use until the last two weeks so trying to work out how to utilise it. But have got a problem with the hive controller, at least it is thought the problem is with the hive controller. That problem is that as soon as it drops a tiny bit below the target temp it fires up again and as soon as it’s passed it, it stops again and repeat, so I spotted I was getting multiple 2-3 minute cycles. NOT GOOD. So I am having to watch it like a hawk and as soon as it hits the target dial the temp back a few degrees to stop it from going off again. I’m trying to gauge ( whilst also waiting to try and get a permanent fix for the problem from BG/hive/Daikin) what temperature I should let it drop to before I restart to get an efficient next cycle. What I have noticed is that across the cycles I have run so far I have been getting a heating gain of around 0.5c per hour. I have also noticed, by looking at my smart meter info, that the first hour of a cycle is using about 1.7kwh v 1.4kwh for each subsequent period. And even though the gain in temp towards the end is significantly less, the power consumption hasn’t changed. If anyone has a view on these things please do respond.

Have a look at my Daikin 8kW heat pump.

It is the same heat pump as yours, just without the software limit in heating mode.

I use a third of the electricity you are using and my heat pump turns on and off only when I tell it to.

I have a Madoka but don't use it. I use no room control whatsoever, you could do the same and use a lot  less electricity.

My heat pump

Emoncms - app view

Another Daikin 8kW

Emoncms - app view

All heat pumps

HeatpumpMonitor.org

oliver1951

matt_drummer said:

oliver1951 said:

Just an update and to see if there are other with British Gas instals. Had mine installed mid June 2024. It’s a Daikin altherma 3 8kw, with a mixergy cylinder and a hive controller. Hasn’t had much use until the last two weeks so trying to work out how to utilise it. But have got a problem with the hive controller, at least it is thought the problem is with the hive controller. That problem is that as soon as it drops a tiny bit below the target temp it fires up again and as soon as it’s passed it, it stops again and repeat, so I spotted I was getting multiple 2-3 minute cycles. NOT GOOD. So I am having to watch it like a hawk and as soon as it hits the target dial the temp back a few degrees to stop it from going off again. I’m trying to gauge ( whilst also waiting to try and get a permanent fix for the problem from BG/hive/Daikin) what temperature I should let it drop to before I restart to get an efficient next cycle. What I have noticed is that across the cycles I have run so far I have been getting a heating gain of around 0.5c per hour. I have also noticed, by looking at my smart meter info, that the first hour of a cycle is using about 1.7kwh v 1.4kwh for each subsequent period. And even though the gain in temp towards the end is significantly less, the power consumption hasn’t changed. If anyone has a view on these things please do respond.

Have a look at my Daikin 8kW heat pump.

It is the same heat pump as yours, just without the software limit in heating mode.

I use a third of the electricity you are using and my heat pump turns on and off only when I tell it to.

I have a Madoka but don't use it. I use no room control whatsoever, you could do the same and use a lot  less electricity.

My heat pump

Emoncms - app view

Another Daikin 8kW

Emoncms - app view

All heat pumps

HeatpumpMonitor.org

Matt, that’s helpful. How did you get to having no software limits in the heating? If you aren’t using the madoka how do you tell it your target temperature, or don’t you use one? From your previous posts I think you are running it pretty much 24/7 to keep the house to a constant temperature and at around 21c, is that correct?
to to recap what I said in the. ‘Octopus’ thread, I have the hive controller because the madoka doesn’t work with my config.

Matt one other thought, with the changes you have made is there any issue with octopus over support/ warranty?

matt_drummer

I haven't changed anything other than radiators so there is no affect on my warranty.

I don't have a target temperature for the house if that is what you mean.

It's a heat pump, it runs best if you just let it run without stopping and starting.

Room thermostats may suit some people and I understand that, but it is an idea linked to gas and oil boilers.

I just set a fixed flow temperature.

If it is too cold I turn it up by 1c, if it is too hot I turn it down by 1c or turn the heat pump off if it is really too hot.

I also monitor the efficiency, not all the time, but regularly, either on a computer or my phone. It is easy to see if an adjustment is necessary.

I don't need a weather curve as my heat output regulates itself enough to keep us comfortable with only the occasional adjustment necessary

This is possible probably because of the size of my radiators but you may need a curve.

This will take time to set up but just take notes of what flow temperature you need at differing outside temperatures.

Then just let it run.

You can make adjustments as necessary from the Onecta app on your phone.

You only need the Hive, or maybe I should say the Hive only turns the heat pump off,  because your flow temperature is wrong. Once you get that set with a wdc your home should stay at whatever temperature you find comfortable without any intervention from any sort of room thermostat.