Octopus Cosy Heat Pump Owners & Discussion Thread - Air Source Heat Pumps (ASHPs)

RE: Octopus Cosy Heat Pump Owners & Discussion Thread

HarrisonC — Sun, 29 Mar 2026 07:06:09 +0000

Went down to 0 degrees last night. Still oscillates a bit but not as bad as before.

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RE: Octopus Cosy Heat Pump Owners & Discussion Thread

swwils — Sat, 28 Mar 2026 18:56:28 +0000

@harrisonc mine is an early 9.

I've seen it under report, but it's about 8% over on SPF. Which is very good for onboard monitoring really.

RE: Octopus Cosy Heat Pump Owners & Discussion Thread

KevH — Sat, 28 Mar 2026 12:40:19 +0000

I have to go into the installer mode and check the version number.

Many thanks. I have yet to enter installer mode, maybe I should take this an ideal opportunity.

RE: Octopus Cosy Heat Pump Owners & Discussion Thread

KevH — Sat, 28 Mar 2026 12:35:35 +0000

I have to go into the installer mode and check the version number.

Many thanks. I have yet to enter installer mode, maybe I should take this an ideal opportunity.

RE: Octopus Cosy Heat Pump Owners & Discussion Thread

HarrisonC — Sat, 28 Mar 2026 10:02:41 +0000

@swwils are you on Cosy 9, as the Cosy 6 definitely doesn't when it modulates down. Does your Cosy heat output under or over-report?

ah should have known it was OEM based on the black line.

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RE: Octopus Cosy Heat Pump Owners & Discussion Thread

swwils — Sat, 28 Mar 2026 09:59:04 +0000

@harrisonc it measures electric exactly and heat within 8% of my MID meter so that's pretty damn good.

It's not HA

RE: Octopus Cosy Heat Pump Owners & Discussion Thread

HarrisonC — Sat, 28 Mar 2026 09:56:33 +0000

@swwils Next thing they need to fix is correctly measuring power. What card are you using for Home Assistant for these out of interest?

RE: Octopus Cosy Heat Pump Owners & Discussion Thread

swwils — Sat, 28 Mar 2026 09:54:24 +0000

It ramps differently now and then doesn't ramp as hard afterwards, there is also much deeper modulation of the heat output. So basically it gets into steady state better and stays in steady state.

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RE: Octopus Cosy Heat Pump Owners & Discussion Thread

HarrisonC — Sat, 28 Mar 2026 08:57:52 +0000

@kevh I have to go into the installer mode and check the version number.

The new behavior seems to kick in after 5 degrees. You can see below where the red line is when the outdoor temp is below 5. The peak just after is the hot water. The green circle is a new behavior as well where it seems to boost to get the flow temp up after a restart. The pink is also new, normally it would be fluctuating like crazy here but it is now pretty stable.

I will have to see how it goes when it gets even colder but hopefully this is a more stable control loop.

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RE: Octopus Cosy Heat Pump Owners & Discussion Thread

swwils — Fri, 27 Mar 2026 12:12:12 +0000

@agentgeorge Cosy 9. It's automatic and remote update. Probably only for 9s