I also found that nearly all HP manufacturers say you should have one otherwise the warranty is invalid. Hopefully this will change as they too come to grips with HP
Do they? That's not what I observe from the several manuals I have read (albeit in some cases fairly quickly, I admit) over the past 2 years. I wonder if @heacol would like to comment about the 'nearly all HP manufacturers say you should have one', given he is so strongly opposed.
I’ve raised this with several manufacturers, and it’s interesting to see how their positions have evolved over the past couple of years. Back then, it was very common for manufacturers to insist on buffers, with some even making them a warranty requirement. Vaillant, for example, was one of the main players pushing this approach, but they now strongly deny that buffers are mandatory.
Many manufacturers stillrecommendbuffers, particularly for systems with complex hydraulics or where zoning might cause issues, but it’s no longer a blanket requirement for warranty validation. The industry is gradually shifting toward more flexible guidelines, recognising that well-designed systems without buffers can perform just as effectively (if not better) in many cases.
I also found that nearlly all HP manufacturers say you should have one otherwise the warranty is invalid. Hopefully this will change as they too come to grips with HP
I love the idea of HP manufacturers eventually getting to grips with HP 🤣
Would it be asking too much for MCS to do the same?
Let's remember that there's a substantial profit to be made by installers adding large tanks... and most UK homes built since the 1970s have very little space to accommodate them.
Yes @uk_pete_2000 , I too think this forum should be able to offer a possible solution to check the balance of a buffer tank, and to allow it to be better configured to optimise efficiency.
That is, after all, a requirement of Building Regs Part-L, Section-8
However, I'm wary of any 'solution' which would require a flow-sensor to be added on the heat-emitters side.
If there's a way of assessing the balance of a buffer by strapping contact-style temperature sensors to the pipes, then householders are much more likely to attempt that.
If there's a way of assessing the balance of a buffer by strapping contact-style temperature sensors to the pipes, then householders are much more likely to attempt that.
One conventional way as I mentioned earlier is sensors at one third and two thirds up the vessel. However buffer tanks are insulated so unless the vessel comes with the sensor pockets pre-installed (which surely all should but probably some dont) not very practical as a retrofit. There also appear to be a lot of LLHs out there, no idea how you balance these.
@uk_pete_2000 I do not think there is 1 manufacturer that insists on a buffer, what they do insist on is adequate open flow and system volume. Flow should be around 2 L/mim/full load Kw and system volume should be around 15l/Kw full load.
You are correct that there is a way of controlling the flow on either side of your buffer, however, it will probably cost more than your entire installation as it will need full active real-time flow and temperature management. The best thing to do is remove it, and if you are worried about your house cooling down, change the buffer to a 2-pipe volumisor on the flow.
There is no difference between a 3-pipe and a 4-pipe buffer, they are exactly the same.
There is no difference between a 3-pipe and a 4-pipe buffer, they are exactly the same
There is plenty of difference in my case.
A 4 pipe 300l buffer, we have to get the balance down below to say 2° flow temp across the top. In order to do that I have to restrict the HP flow.
As the HP has a greater flow then the central heating side ( and yes I have tried all three setting on both the HP and the CH pumps), we use the ball valves to slow the HP flow ( mine was not fitted with a flow meter, even though it should have been).
If we go to a three port buffer and fit a flow meter, we are then forcing all the flow temp into the CH side, thus allowing us to drop the HP flow to 23 to 25°.
Having read @jamespa reply on open loops, if we remove the buffer and change to an open loop then when our system does a 12 hour, anti-freeze cycle all the heat in the house will be drawn out into the heat pump, rather than being confined to a buffer. It will not make any difference when defrosting.
I’ve raised this with several manufacturers, and it’s interesting to see how their positions have evolved over the past couple of years. Back then, it was very common for manufacturers to insist on buffers, with some even making them a warranty requirement. Vaillant, for example, was one of the main players pushing this approach, but they now strongly deny that buffers are mandatory.
@uk_pete_2000 I do not think there is 1 manufacturer that insists on a buffer, what they do insist on is adequate open flow and system volume. Flow should be around 2 L/mim/full load Kw and system volume should be around 15l/Kw full load.
If they did in the past but dont now then there are at least three contractual questions that arise
1. If they insisted on a buffer as a condition of warranty, and didn't provide the means to control it, then is there a claim for mis selling on the grounds that they advertise a COP which in practice cannot be achieved in the system they have sold you
2. If they formerly insisted on a buffer as a condition of warranty but dont now, is it the case that the warranty will now be honoured if you remove the buffer
3. If they formerly insisted on a buffer as a condition of warranty but dont now, why, was the previous insistence a mistake, and should it be removed under warranty given (1)
Of course pursuing these questions (other than (2)) would not be easy, but given that there are several 100,000 installations a good proportion of which are likely to be materially compromised, someone might be tempted to have a go!
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
Would it be asking too much for MCS to do the same?
I wish they would. Ours made out we needed a 13kw system. More because of the size of the house, then the makeup of it. Seems back then it couldn't cope with our wall thickness etc.
Having looked over various figure we could have gone down to a 5kw system and still been over capacity.
Having read @jamespa reply on open loops, if we remove the buffer and change to an open loop then when our system does a 12 hour, anti-freeze cycle all the heat in the house will be drawn out into the heat pump, rather than being confined to a buffer. It will not make any difference when defrosting.
The defrost energy has to come from somewhere, ultimately from the heat pump!
Just to be clear I have neither a buffer nor a volumiser in my system and obviously defrost stops the house being heated for a while but doesn't actively cool it. Even if the defrost water comes from a buffer it still has to be replaced, depleting the energy to the house. I read that Viessman pre-heat a specific defrost buffer which is then 'released' for the defrost operation. Is this over-engineering? Dunno.
This post was modified 1 month ago 2 times by JamesPa
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
I also found that nearlly all HP manufacturers say you should have one otherwise the warranty is invalid. Hopefully this will change as they too come to grips with HP
I love the idea of HP manufacturers eventually getting to grips with HP 🤣
Would it be asking too much for MCS to do the same?
Let's remember that there's a substantial profit to be made by installers adding large tanks... and most UK homes built since the 1970s have very little space to accommodate them.
Yes @uk_pete_2000 , I too think this forum should be able to offer a possible solution to check the balance of a buffer tank, and to allow it to be better configured to optimise efficiency.
That is, after all, a requirement of Building Regs Part-L, Section-8
However, I'm wary of any 'solution' which would require a flow-sensor to be added on the heat-emitters side.
If there's a way of assessing the balance of a buffer by strapping contact-style temperature sensors to the pipes, then householders are much more likely to attempt that.
I don't believe the installation of a buffer tank, complies with the building regulations.
If there's a way of assessing the balance of a buffer by strapping contact-style temperature sensors to the pipes, then householders are much more likely to attempt that.
One conventional way as I mentioned earlier is sensors at one third and two thirds up the vessel. However buffer tanks are insulated so unless the vessel comes with the sensor pockets pre-installed (which surely all should but probably some dont) not very practical as a retrofit. There also appear to be a lot of LLHs out there, no idea how you balance these.
Just thinking about this measuring the temperatures on all 4 ports should, I think, provide enough information to achieve a reasonable balance. Somebody has to design the control circuit though and provide for various situations like defrost, cycling etc. It feels doable in principle, but is anyone going to bother particularly as they will also have to deal with the myriad of options of how the pumps are configured/currently controlled.
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