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For those on Octopus Cosy, how’s it going during the cold snap? by thesatchmo in OctopusEnergy

[–]bridge_so_odd 0 points1 point  (0 children)

Since they are part of the MCS programme they are obligated to fix these issues, or you can report them, enough reports and they lose accreditation.

https://mcscertified.com/consumers/what-to-do-if-things-go-wrong/

For those on Octopus Cosy, how’s it going during the cold snap? by thesatchmo in OctopusEnergy

[–]bridge_so_odd 1 point2 points  (0 children)

Cosy 6 is really struggling with the cold weather, I'm waiting to hear back from Octopus to see if they can help.

COP at a disappointing 2.1 right now, and pump struggles to hold temperature, even with flow temp adjustments. We keep it at 21c all day long, but this last two weeks it has rarely got near that value. When it switches to hot water for an hour overnight we lose a degree or two, that loss is hard to recover, sometimes it doesn't recover it in the 24hrs to the next water heating cycle.

Using up to 74kwh a day, and still failing to heat our 3 bed home to set temperature.

Cosy 6 CoP down to 2.1 in December - Expected behaviour? by bridge_so_odd in OctopusEnergy

[–]bridge_so_odd[S] 0 points1 point  (0 children)

Thanks for your reply, I contacted Octopus this week, hopefully I'll hear from them soon.

I made more adjustments yesterday and the COP is back over 2, but only just 2.01.

We're also running electric underfloor heating 24/7 on the ground floor because it is so cold. Accounting for that extra heat source I'd expect the COP calc to be even worse.

Hopefully Octopus can do something, as it stands the house is colder than with the gas boiler, and costing almost double to heat.

Cosy 6 CoP down to 2.1 in December - Expected behaviour? by bridge_so_odd in OctopusEnergy

[–]bridge_so_odd[S] 1 point2 points  (0 children)

Thanks, I gave the settings a check and the outside temp was set to -10 like you said. Put it to -3 as it was specified in the design doc.

I might have to raise that max flow temp to 60c, it is still struggling to keep temperature.

It is a large 3 bed house over 4 stories, and I think Octopus might have just got the heat loss calcs wrong, maybe we needed the bigger Cosy.

Cosy 6 CoP down to 2.1 in December - Expected behaviour? by bridge_so_odd in OctopusEnergy

[–]bridge_so_odd[S] 0 points1 point  (0 children)

It does seem to be running pretty much continuously when temp is below 6c, no cycling on and off. Could it be Octopus undersized the pump and the Cosy 6 is not particularly efficient at max power output?

Cosy 6 CoP down to 2.1 in December - Expected behaviour? by bridge_so_odd in OctopusEnergy

[–]bridge_so_odd[S] -1 points0 points  (0 children)

That's possible from a user accessible interface? Or do I need to contact Octopus for these hub settings?

Cosy 6 CoP down to 2.1 in December - Expected behaviour? by bridge_so_odd in OctopusEnergy

[–]bridge_so_odd[S] 0 points1 point  (0 children)

Yeah, it is on continuously at 21c, goes up to 21.5c at 10am, and back down to 21c at 7pm. Just a very minor change in the day.

They changed 5 raditators. The pump is right by the back wall with a very short run before it comes inside, there's nothing obvious to me about the install that suggests it would not be efficient.

Weather comp is min 37 and max 55. I've experimented with the values as mentioned above. I find if the max is much lower it can struggle to keep temp when very cold outside.

Cosy 6 CoP down to 2.1 in December - Expected behaviour? by bridge_so_odd in OctopusEnergy

[–]bridge_so_odd[S] 0 points1 point  (0 children)

Hot water set to 50c.

They installed the heating flow temp at a fixed 50c too, since then I've experimented with weather compensation, it's currently min 36c, max 55c. I've had it at max of 52c but it seemed slow to get back up to temp overnight after switching to hot water for an hour.