@editor That image is from my brand spanking new 13 inch iPad pro screen The iPhone screen is far too small to use for any serious browsing work. Regards, Toodles.

@toodles Ah, I see. Since you have so much screen real estate, I'll see if I can make it bigger 😉 

Jokes, aside, it'll have to remain the way it is for now...

@editor It is like having an impetuous and very curious 5 year old at your elbow!😉 Toodles.

Posted by: @toodles

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@editor It is like having an impetuous and very curious 5 year old at your elbow!😉 Toodles.

Child, grandchild or labrador?

Speaking personally, no grandkids yet so can't comment. Kids are adult now so less impetuous and far more likely to tell me I'm wrong than ask what I'm doing. Labrador is a good candidate but Wattson so far hasn't prodded me with a wet nose.

@majordennisbloodnok 🤣

@majordennisbloodnok That’s OK, as long as Wattson doesn’t keep prodding me to go ‘Walkies’. I have grand children and yes, they have both fitted my description at one time or another! Toodles.

i asked it the buffer question :0

oh I have asked it about 20 questions now, this is going to be my new toy, so far so good with the answers!

I asked the buffer question also ("should I fit a buffer tank?").  It said (in summary) probably no and then went on to say:

'Instead, many experts now recommend using volumisers or optimising hydraulic separation without a buffer tank. These approaches can provide the necessary system volume and separation without the downsides of a buffer tank'

What is 'optimising hydraulic separation without a buffer tank', I wondered, so I asked and it responded

You're very welcome! When I mention "optimising hydraulic separation without a buffer tank," I’m referring to designing the heating system so that the heat pump circuit and the heating distribution circuit (like your radiators or underfloor heating) are hydraulically separated without needing a bulky buffer tank in between.

Hydraulic separation means ensuring that the flow rates and pressures on the heat pump side and the heating side can operate independently and smoothly, avoiding issues like flow rate mismatches or pressure drops that can reduce efficiency.

Instead of using a buffer tank to achieve this separation, installers can use devices like volumisers or hydraulic separators (sometimes called low-loss headers). These are designed to allow the heat pump and heating circuits to run at their optimal flow rates without mixing water temperatures inside a tank, which avoids the “distortion” problem buffer tanks can cause.

The benefits of optimising hydraulic separation without a buffer tank include:

• Maintaining better control over water temperatures and flow rates
• Reducing mixing of hot and cold water, so the system runs more efficiently
• Avoiding the extra cost, space, and electricity use of buffer tanks and additional pumps
• Keeping the system simpler and easier to manage

This approach is more in line with modern heat pump designs, which are built for precise modulation and control, so they don’t need the extra volume or blending that buffer tanks provide.

So I pursued the line of questioning with a follow up "OK, however (a) a volumiser doesnt normally provide hydraulic separation (and if it does it will suffer from the same problems as a buffer tank) and a LLH suffers from many of the same problems as a buffer tank. Is it better still simply not to have hydraulic separation"

to which it responded:

You’ve raised a very insightful point! Indeed, volumisers typically provide system volume but don’t always offer true hydraulic separation, and low-loss headers (LLHs) can share some of the same challenges as buffer tanks, such as mixing and added complexity.

Whether to have hydraulic separation at all depends on the specific system design and components. In many modern heat pump installations, especially well-designed ones with matched flow rates and properly sized pumps, it’s possible—and often preferable—to avoid hydraulic separation altogether. This means the heat pump circuit and heating circuit operate as a single hydraulic loop, simplifying the system and reducing potential inefficiencies caused by mixing or extra components.

However, in some cases, hydraulic separation is necessary—for example, when the heat pump and heating circuits have very different flow requirements or when multiple heating zones are involved. In these situations, careful design is essential to minimise mixing and flow issues, whether using volumisers, LLHs, or other methods.

The key takeaway is that buffer tanks, volumisers, or LLHs are not a one-size-fits-all solution. The best approach is a well-engineered system tailored to the heat pump’s characteristics and the home’s heating needs, aiming to keep flow rates matched, water temperatures stable, and controls optimised.

If you want to explore this further or discuss specific system designs, our forums are a great place to connect with installers and homeowners who’ve faced similar questions. And the expert discussion on buffer tanks at Renewable Heating Hub offers valuable insights too: https://renewableheatinghub.co.uk/are-buffer-tanks-making-your-heat-pump-less-efficient/ .

Not bad, but definitely not quite as good as a good human yet!

Has it taken the heat pump quiz that was published earlier in the year?

Posted by: @jamespa

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Not bad, but definitely not quite as good as a good human yet!

Agreed. For an attempt at the start of the tweaking journey I’m happy. Does need rough edges being smoothed but as you say, @jamespa, not bad.

@ashp-bobba ‘Wattson, how many grammes of Co2 are you responsible for on the average search and reply? 😉