Octopus Heat Pumps

Spies

So after obsessing over this and looking back at some thermal imagery I took when we had the very cold snap in January, it appears the floor of my lounge, (which is overhanging fresh air in its entirety) does actually have insulation, this reduces by heatloss (according to heatpunk) by around 600w, which makes the whole home heatloss just 5kw which is a much better figure for a 6kw heatpump to cope with, this likely means 45c at -2.2 would be doable.

oliver1951

matt_drummer said:

FreeBear said:

Installing a heat pump at the front (assuming there is a suitable spot) would need planning permission I believe. Not an insurmountable problem if the local authority is agreeable - Central government are pushing for planning departments to relax rules a little so that net zero targets can be achieved.

The heat pump specs I looked at generally specify a maximum of 10m of pipework to the DHW tank. That would be one sticking point for me. That said, I do have an alternative location that could be used at the expense of a longer pipe run to the bathroom. Boils down to trade-offs and compromises.

No, the front of the house is permitted development as long as you follow the rest of the rules.

I know because my heat pump is on the front of the house, it's the only place the council couldn't object to!

I put mine in at the front of the house too, only place it would work, however PP was required and it took 15 months! Not a happy time.
Anyway, mine was installed in June and yesterday for the first time it kicked in. ( apart from for DHW) . I’m still a little bit confused about how it’s working. Because it seems to be operating with no tolerance around the target temperature. Ie it drops a little below, it kicks in and then as soon as it’s got there it switches off again. Then the temp drops below target and it kicks in again, temp reaches target and it drops out again. Isn’t that short cycling? 

Spies

What's the overshoot value set to under Space heating on the MMI?

oliver1951

Spies said:

What's the overshoot value set to under Space heating on the MMI?

Good question. I have no idea, I’ll take a look in the morning. What should it be set too?

Reed_Richards

It should be set to a number large enough to cause the cycles to be at least 10 minutes in duration and therefore not "short".

oliver1951

oliver1951 said:

Spies said:

What's the overshoot value set to under Space heating on the MMI?

Good question. I have no idea, I’ll take a look in the morning. What should it be set too?

I have the advanced user PIN code, but clearly I’m doing something wrong because I can’t seem to get it confirmed. I set the code and am using the left hand , big button, to confirm, but it isn’t confirming. So I can’t get into the sub menus. Any thoughts?

rjmachin

Do you need the "Installer" pin code (5678) to access it?

oliver1951

Can’t clear….

oliver1951

rjmachin said:

Do you need the "Installer" pin code (5678) to access it?

Ok, ignore one above, I got a really weird issue while trying to post my response.
anyway I have previously used the advanced user code, 1234, but this time the system doesn’t seem to be confirming it. So I am entering in the code, then pressing the left big button, and the screen goes a bit odd, but I can’t get below the top level, so it’s clearly not accepted the code.

matt_drummer

Spies said:

What's the overshoot value set to under Space heating on the MMI?

Overshoot is normally adjustable between 1c and 4c, but may not be depending on the heat pump, the heating mode chosen and the firmware installed on the heat pump.

My 8kW required a firmware update to make the adjustment possible in radiator mode, it was locked at 1c before the update.

Overshoot sets the amount the heat pump can exceed the requested flow temperature, either a fixed flow temperature or that determined by the weather dependent curve.

There is also modulation which is only adjustable once activated and only in use if using the Madoka to control room temperature. It is adjustable between 1c and 10c and is what is known as load compensation.

Neither of these setting will change what is going on with @oliver1951

What you are seeing is the hysteresis on the room temperature control. It is 2c and not adjustable.

If the room temperature is set at 20c then the heat pump will turn off at 20.5c and come back on at 18.5c.

I don't like it and it is one reason I don't use it.

You can make it take longer to get to the required room temperature by reducing heat output but once the required temperature +0.5c) has been reached the house has to cool by 2c before the heat pump will come on again.

It's uncomfortable for me and I wanted a constant heat.

I also found it inefficient in terms of COP.

The heat pump runs less but when it is running it uses more electricity at a lower COP.

So, if you want 20c, set it to 21c, it will heat to 21.5c and come on again at 19.5c

With regard to user profile, you can adjust very little as an advanced user (code 1234). You need to go into installer settings (code 5678) to make any real changes.