@drew-pa

I am at the moment giving serious consideration to engaging the services of @heacool to run his expertise over my install.  I have a feeling he will make such changes as you indicate and have my system running far more efficiently.  My concern, which I am trying to get to grips with, is how his work might affect my warranty with my installer and Mitsubishi.  Also if having changes made by a third party affects my RHI situation.

I'm pleased for you that your system is so efficient, you clearly are very happy.  If you can achieve such progress given your northerly location I should be able to achieve similar this far further south in Derbyshire.    Good luck.

Posted by: @drew-pa

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 We managed to get a COP for February of over 5.2. I’m astounded!  

And so you should be!

When I get a read out on my car dashboard telling me I am getting 250 mpg I also tend to be astounded.

Given the ambient temps you have experience over the last month, is that COP credible? How does it compare to Valliant's claimed performance at those ambients and your heat pump settings (LWT etc)?

Posted by: @cathoderay

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Posted by: @drew-pa

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 We managed to get a COP for February of over 5.2. I’m astounded!  

And so you should be!

When I get a read out on my car dashboard telling me I am getting 250 mpg I also tend to be astounded.

Given the ambient temps you have experience over the last month, is that COP credible? How does it compare to Valliant's claimed performance at those ambients and your heat pump settings (LWT etc)?

 

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If you take the DHW out of the equation, maybe.

Posted by: @fazel

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If you take the DHW out of the equation, maybe.

Sorry, that doesn't make sense.

The medium/long term COPs shown in that unexplained and unidentified link are around 4.2. The COPs listed on heatpumpmonitor.org range from 2.5 to 4.9, mean 3.7, median 3.9. That's why I question whether a COP of 'over 5.2' is credible in winter in Scotland.

Unless you have third party monitoring hardware that is correctly set up, you are relying on manufacturers generated data, effectively the manufacturer marking their own homework. We have no way of knowing how scrupulous they are, though we do know that certain car manufacturers have been known to mark their own homework creatively.     

Posted by: @cathoderay

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Posted by: @fazel

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If you take the DHW out of the equation, maybe.

Sorry, that doesn't make sense.

The medium/long term COPs shown in that unexplained and unidentified link are around 4.2. The COPs listed on heatpumpmonitor.org range from 2.5 to 4.9, mean 3.7, median 3.9. That's why I question whether a COP of 'over 5.2' is credible in winter in Scotland.

Unless you have third party monitoring hardware that is correctly set up, you are relying on manufacturers generated data, effectively the manufacturer marking their own homework. We have no way of knowing how scrupulous they are, though we do know that certain car manufacturers have been known to mark their own homework creatively.     

The Vaillant range is relatively new and should be at the higher end of COPs out there. However, 5.2 for February might be a tad optimistic given the Vaillant SCOPs listed below, which are measured on test rigs, not real houses.  

Having said that, it sounds like @drew-pa's system is running efficiently and has made good improvements. 

Posted by: @cathoderay

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Posted by: @fazel

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If you take the DHW out of the equation, maybe.

Sorry, that doesn't make sense.

The medium/long term COPs shown in that unexplained and unidentified link are around 4.2. The COPs listed on heatpumpmonitor.org range from 2.5 to 4.9, mean 3.7, median 3.9. That's why I question whether a COP of 'over 5.2' is credible in winter in Scotland.

Unless you have third party monitoring hardware that is correctly set up, you are relying on manufacturers generated data, effectively the manufacturer marking their own homework. We have no way of knowing how scrupulous they are, though we do know that certain car manufacturers have been known to mark their own homework creatively.     

The Vaillant range is relatively new and should be at the higher end of COPs out there. However, 5.2 for February might be a tad optimistic given the Vaillant SCOPs listed below, which are measured on test rigs, not real houses.  

Having said that, it sounds like @drew-pa's system is running efficiently and has made good improvements. 

Posted by: @kev-m

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Having said that, it sounds like @drew-pa's system is running efficiently and has made good improvements. 

I am sure it is running efficiently, and that is a good thing, but I think we have got to be realistic about performance figures. The 'over 5.2' COP for February is also significantly at odds with @drew-pa's previously published monthly COP figures (<=link) eg 3.85, 3.78, 2.94 for October, November and December 2022. That makes the 5.2 figure a significant outlier, and significant outliers often tell us something is wrong with the data behind the outlier.

Evening all,

I have to say we are extremely happy with the whole package regardless of whether there are errors in the data or not.  I have seen the numbers improve over the year as the changes we have made have taken effect.  We are really happy with the installation as a whole, the installer, and the equipment.  Really happy.  

I have used figures from the app to complete the spreadsheet so that may explain some differences.  Going forward I am going to only use the vrc720f energy data so the data set is constant.  

We have made some big changes over the year since it was installed first.  Hopefully we have just completed the last upgrades now.  When the system was first installed we had heat curves of 1.2 and 0.8 I think it was.  These are now down to roughly 0.35, the adaptive heat curve appears to be working well. We are seeing a flow temp of 32-34c now.  Our COP since install, taken from the VRC720F is 4.14 for the whole installation. 

Like I said earlier we are extremely happy with the install.  I have learned so much, both about the system, and to not be scared of the system and to try different things till you find what works for you and your system.  A big thank you to everyone here for your help, and knowledge transfers. 

Take care all.