@l2jad Glad to hear it. Hope it'll be sorted for us all. 

BTW, did they install a 4 port buffer or a 2 port volumizer for your system?

From an earlier conversation on here, I was told that the if the volumizer/buffer is 4-port system is about 15% less efficient. I've asked Octopus for an explanation of why a 4-port system, and not a 2-port system was installed, heard nothing back so far.

@razz I’d certainly love to hear their rationale for a 4 port… definitely update if they get back to you.

@razz its a 4 port system they installed

How has everyone been finding the latest firmware update? My Cosy 12 is a bit quieter but still above 61dB 

@harriworld yes mine although better is still not right, had to turn it off at 2am was just going mad. Way too loud!!

i am setting up the deci meter tonight to check every minute and record. Meeting the head design lady next week. Was very stressful here again last night even 3 year old woke from the racket she normally just sleeps through anything, it affects everyone. Really don’t understand sometimes it’s perfectly quiet under 50db then boom off it goes, fan spins up and you can hear it through double glazing!!

Do you notice what causes yours or is it random? Still they are looking at it as know they have a problem, its a good company so no doubt will sort.

tonight i’m turning off the hot water cycle to see if that is having an affect? Will just boost in the morning.

but hey ho getting old so don’t need sleep!!

@harriworld it's better but hard to tell so far how much better. I'm really not going to believe a fix until we get some cold weather to test it, need some sub 5deg temps.

@livinggreen Colder temps definitely set it off. Mine had been less loud but still registered and 70db this morning. And the house is taking all day to get to temperature. I would still like it to be quieter (nearer the 61db would be an improvement). Although at point of sale I was told it would be 40db!!

@l2jad What time is your hot water cycle set for?

@editor Another heat pump engineer/installer from Octopus came by. He said, the reason for the use of a 4 port buffer is to get "hydraulic seperation", couldn't explain what exactly that meant because he himself apparently doesn't do this very often.

Then he explained that when they first rolled out the cosy 6 and 9, they used a buffer and eventually switched to using volumisers. Since the 12 is so new, they're playing it safe by using a buffer, and that eventually they'll likely be using volumisers too.

Which isn't much consolsation for me, as my heating bill is a fair bit higher, while having a colder home. 

He also told me that they're getting a lot of calls about the cosy 12.

EDIT: I just saw your brilliant video on buffers, really do think Octopus might have made the mistake you mentioned. 

They put in absolutely HUGE K3 radiators in my house that are a genuine nuisance by how much space they take up, which is one of the ways to compensate for the water mixing caused by a buffer.

@harriworld it was roughly 3am  for  an hour as that’s my cheap iog time, my water heats to 50 degree quickly as its generally still quite high in the cylinder. originally the intension was to then raise the house temperature after the hot water cycle by a degree using cheap energy haven’t bothered just want peace and quiet!!!, the house loses heat very very slowly so normal house day time is temperature is 18 or 18.5. 
i moved hot water to between 6 and 7am after the earlier time woke the wife, daughter and grand daughter.

my house warms up very quickly being its generally only a degree out, rads get warm 50 degree flow. Bedrooms are turned down as gets too hot. The pods are within .5 a degree at most.

@razz, unfortunately ‘hydraulic separation’ has become a comfort blanket phrase for poor installers. It’s not inherently evil, but it’s also not a free lunch. A 4-port buffer guarantees mixing on some level, and mixing means lower emitter temperatures, worse efficiency and higher bills. 

What I find genuinely disconcerting is the idea that Octopus appear to be defaulting to a buffer or volumiser as policy. Very few homes ever genuinely need a buffer tank with a heat pump. A volumiser is only required where system volume is genuinely short, which again is not a blanket condition. 

The line about “Cosy 12 is new so we’re playing it safe” is also worrying. If the system needs hydraulic crutches because the model is new, that risk is being pushed straight onto the homeowner in the form of potentially higher bills and poorer comfort. Your experience (higher costs and a colder house) is exactly what you’d expect when a buffer is masking design issues rather than solving them.

This is why blanket approaches in heat pump design are dangerous. Heat pumps reward precision and punish laziness. Buffers (extremely rarely) and volumisers have a place, but when they become default fittings rather than last-resort tools, the system is already compromised.

Well last night i set the system how i want it to run17.5 day and night with 18.5 afternoon and evening. Hit water early hours as i’m on iog. Their fix has quietened down the fan no end. I didn’t get an ear full from the mrs. Now as is it is very acceptable, now it is mild so reserve judgement when its cold out. But 1000.% improvement.

slight rumble from red pump.

my tank is plumbed 4 pipes was told to do with defrost cycle.

This morning figures, at one point hit 4.9 cop