@jamespa Thanks.

I did not instruct them not to insulate but I surmise they made the same decision as yours? There are lots of pipes there in a small space, so ventilation may be quite relevant, but I may ask them why they did not do it?

Right now I am questioning if I should ask them to come back to cut and fix the two slabs I asked them to leave so that it would make my life easier not to do this job on my own, but I am not sure if I have the right to ask for it (picture attached).

 I am not so sure now if I should purchase Heavenwise, but as you said, it may offer benefits with some tariffs. I have signed up for Octopus cosy, while I am waiting for them to let me know if I could use intelligent flux (which combines the perk of having batteries).

They said that service will cost £150 which felt a little bit pricey when compared with the £80 I was used to paying for boiler service.

Posted by: @eliuccio

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I did not instruct them not to insulate but I surmise they made the same decision as yours? There are lots of pipes there in a small space, so ventilation may be quite relevant, but I may ask them why they did not do it?

Strictly they should be insulated (building regs I believe) to stop them 'leaching' heat from the tank, unless of course you want the heat for something else!

Posted by: @eliuccio

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 I am not so sure now if I should purchase Heavenwise, but as you said, it may offer benefits with some tariffs. I have signed up for Octopus cosy, while I am waiting for them to let me know if I could use intelligent flux (which combines the perk of having batteries).

I think if I were on a relatively complex tarrif like Cosy I would probably opt for Havenwise, but I haven't got batteries which I gather you have.  The Vaillant controls are extremely flexible and, unlike many of Vaillant's competitors, setting a time pattern changes the flow temperature rather than just switching it on and off.  They are therefore undoubtedly capable of doing what is necessary to optimise for a complex tariff of this nature, but my brain isn't capable of working out what settings I would need to put in!

Posted by: @eliuccio

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They said that service will cost £150 which felt a little bit pricey when compared with the £80 I was used to paying for boiler service

There was a whole thread about service costs and yes they appear to be high.  If it includes the UVC service/inspection then perhaps a bit less so, worth asking.

Posted by: @eliuccio

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Right now I am questioning if I should ask them to come back to cut and fix the two slabs I asked them to leave so that it would make my life easier not to do this job on my own, but I am not sure if I have the right to ask for it (picture attached).

Personally i would say this is reinstatement which they should have done, but there is room for argument depending on the precise words of the contract.  You need an angle grinder to cut the slabs, if they have one and you don't I would try to persuade them to do it!

Thanks @Jamespa!

Posted by: @jamespa

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Strictly they should be insulated (building regs I believe) to stop them 'leaching' heat from the tank, unless of course you want the heat for something else!

I will ask them why they are not and will also try to persuade them

Posted by: @jamespa

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I think if I were on a relatively complex tarrif like Cosy I would probably opt for Havenwise, but I haven't got batteries which I gather you have.  The Vaillant controls are extremely flexible and, unlike many of Vaillant's competitors, setting a time pattern changes the flow temperature rather than just switching it on and off.  They are therefore undoubtedly capable of doing what is necessary to optimise for a complex tariff of this nature, but my brain isn't capable of working out what settings I would need to put in!

Right now, Octopus offered these options:

1. Switch to Intelligent Octopus Flux (Import and Export): This would mean changing your current Cosy Octopus import tariff and your existing export tariff (if you have one) to Intelligent Octopus Flux. This option is ideal for maximising your solar and battery usage with dynamic import and export prices.
2. Keep Cosy Octopus (Import) and Pair with Outgoing Octopus (Export): You could stick with Cosy Octopus for your import (which is great for heat pumps) and then pair it with our Outgoing Octopus tariff for your export. Outgoing Octopus offers a competitive flat rate for the energy you send back to the grid.

 So, I will have to work out what is best.

Posted by: @jamespa

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There was a whole thread about service costs and yes they appear to be high.  If it includes the UVC service/inspection then perhaps a bit less so, worth asking.

I will certainly ask!

Cheers!

E

Posted by: @eliuccio

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 So, I will have to work out what is best.

Indeed.

With a battery its presumably the battery controller that does all the heavy lifting with load optimisation, so I'm not sure Havenwise helps much, but that depends on size of battery and controller capabilities.  You may need a years worth of data to work it all out for certain.  I have been collecting data since I had my heat pump fitted so I have got some basis to work out a strategy as tarrifs shift.

Hello folks,

I thought it was worth updating on my journey.

My Vaillant aroTHERM plus 5 kW combined with Vaillant uniSTOR Heat Pump Cylinder 150 litre seems to work fine.

I only had to increase pressure (from 1.6) from time to time and slightly adjust the weather compensation mode (the latter may still be refined, and I welcome any suggestion advice!).

I should perhaps start by mentioning my settings:

- Hot water is set at 43 C (I run a 50 C legionella cycle once a month) 

- Heating is set to time-controlled mode and the time of activity is scheduled according to the Octopus intelligent go tariff (with a max target temp of 20 C in the evening). Setback temp is 14. The heating curve is set with i) steepness: 0.45 ii) min flow: 16 C iii) Outdoor switch off temp: 15 C  

The HeatGeek design promise was 3.9 SCOP at 45 C.

Here's the efficiency of the system as reported by the Myvaillant app.

• The first full month of activity was August, featuring 3.66
• September was 4.29
• And even more representative was October at 4.49

Based on this data, I feel confident that the system is working better than promised (at least based on the app readings).

I haven't been billed since August yet so difficult to say how much I am saving...

@eliuccio For what it is worth, here is my take on using a TOU tariff and battery to power the home with heat pump. During the summer months, I might well go back to Intelligent Octopus Flux but, for the rest of the year I am on Octopus Cosy. The eight cheapest hours being spread through three periods of the day and night mean I can keep my 27 kWh Powerwall topped up using the Tesla app and never need to use grid power outside those eight hours at all. No EV so cannot contemplate an overnight approx. half price rate to fill my boots. I have 8.1 kWp of solar but of course the winter months rarely provide more than ~8 kWh of energy per day … but every Watt helps! Regards, Toodles.

@toodles sounds good. I started with cosy but then plugged an EV charger and it seems obvious I should have gone for Octopus go. But I guess I may be able to tell if it was worth in a few months time... Cheers!

If the Vaillant is a 7kw unit I’d avoid. Quiet outside noisy inside when it’s going full on. They have a problem with compressor vibration being transferred into the house pipework, so if your primaries will be running through the house like mine it will transfer the humming noise inside.

@adamk apologies but did not understand what exactly you would avoid. can you elaborate? Thanks!

Posted by: @adamk

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If the Vaillant is a 7kw unit I’d avoid. Quiet outside noisy inside when it’s going full on. They have a problem with compressor vibration being transferred into the house pipework, so if your primaries will be running through the house like mine it will transfer the humming noise inside.

we have a 7kW Valliant which has been running quietly and well for a year with a very satisfying SCOP of 4.7. Other people have had noise issues eg @jamespa who had to fiddle with settings to keep it quiet overnight. 
So I wouldn’t say avoid but be aware you may need to follow James’ advice on how to quieten it.
Our primary pipe work is very short outside and then <3m up through the old garage (now workshop) to the changeover valve in the airing cupboard directly above. So the total length will be on the shorter length range of the distribution of installations.

@judith I haven't noticed any noise myself yet, nor my neighbours complained.

Hopefully, it won't be an issue but it's relieving to know that if needed I can rely on people's expertise here!