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Newbie: utterly confused with my Mitsubishi Zubadan air source heat pump running on 55C set flow temperature

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(@davidnolan22)
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It’s got a zone valve, isnt that just the flow and return to the manifold 


   
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(@sandman1600)
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@davidnolan22 What would I be looking for if I'm looking for a header? Is it going to be obvious?

@JamesPa The uninsulated pipe is from the original install and its going to the valve I queried earlier. The heavily lagged pipework is the stuff that was used as part of the heat pump install.

I've attached a few more photos around the tank to see if there's anything that looks notable. 

 

IMG 4426
IMG 4427
IMG 4431
IMG 4429
IMG 4428
IMG 4430

   
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(@davidnolan22)
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there is a lot of pipes going in out of that tank, its that a HWT and buffer in one? you got a tank anywhere else in the house?


   
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(@jamespa)
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Posted by: @sandman1600

@davidnolan22 What would I be looking for if I'm looking for a header? Is it going to be obvious?

A header (or low loss header - LLH) can be identified because

  • flow from HP and
  • flow to emitters and
  • return from emitters and
  • return to HP

all join either end of a pipe.  Here is a diagram, in this case showing two flows/returns to/from emitters - there need be only 1.

It can literally be a 28mm or 32mm pipe, or it might be fatter, some are even square section.

Its quite difficult from the pictures to tell what is connected to what!

This post was modified 1 day 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.


   
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(@sandman1600)
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Posted by: @davidnolan22
there is a lot of pipes going in out of that tank, its that a HWT and buffer in one? you got a tank anywhere else in the house?

This is the only tank we have. I can't see any reference on the tank to a buffer and it was never mentioned when it was being installed... not that this means anything.

They said they'd included a lot of air vent pipes (no idea why) and something to help with hard water. Other than that, I'm in the dark.

@JamesPa I've looked at everything that's not hidden by lagging and I can't see anything but honestly, I'm baffled by it.

I think I need to go back to them now and just raise my concerns and see if they can maybe get somebody else to look at it. They're a big company with loads of different teams with different skill sets so maybe somebody there is better equipped to take a look.

 

 


   
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(@jamespa)
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Posted by: @sandman1600

They said they'd included a lot of air vent pipes (no idea why)

On other threads people complain about gurgling, which is due to dissolved air coming out of solution during the first couple of weeks.  It took nearly a month for mine to clear and unfortunately this involved bleeding a radiator every 2-3 days because there was a high point not portected by a vent'  I guess they are trying to avoid that.  Not a silly decision

Posted by: @sandman1600

I think I need to go back to them now and just raise my concerns and see if they can maybe get somebody else to look at it. They're a big company with loads of different teams with different skill sets so maybe somebody there is better equipped to take a look.

Very sensible at this stage, you probably have all the data you are realistically going to collect.  Hopefully its better now you have reduced the FT somewhat, but I cant help feeling it could/should be better still.  

 

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.


   
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(@davidnolan22)
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IMG 8131

I think you have a 50L buffer at the bottom of the tank. this adds a bit of compelxity, but I think you need a good chat with installer.

 

 

This post was modified 1 day ago 2 times by davidnolan22

   
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(@sandman1600)
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@jamespa That's good to hear about the vents. Gives me some faith that they knew what they were doing.

I'll update as and when I progress this and fingers crossed there's a satisfactory resolution. In the meantime I'll keep tweaking the WC and see if I can get it lower without affecting our comfort temperatures and hopefully improve the COP.

Thanks again for the guidance and thanks to everyone on this thread that's offered really constructive help. It's been invaluable..

 

 


   
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(@jamespa)
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Posted by: @davidnolan22

 

IMG 8131

I think you have a 50L buffer at the bottom of the tank. this adds a bit of compelxity, but I think you need a good chat with installer.

 

 

Well found.  If that's the case and assuming it's 3 or 4 port not 2 port that could account for another 10-15%.  Ideally it needs to go but installers will probably BS a 'reason' for it being there.  

 

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.


   
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(@sandman1600)
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Posted by: @davidnolan22

I think you have a 50L buffer at the bottom of the tank. this adds a bit of compelxity, but I think you need a good chat with installer.

Apparently its the 210ECYLPPSS model which I think might be a bespoke/modified version of their Climacyl range.

IMG 4432

It's here:

Looks like a 50 litre integrated buffer vessel. So is this another headache?

 

 

This post was modified 1 day ago by Sandman1600

   
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(@jamespa)
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Posted by: @sandman1600

So is this another headache?

Yes 

The problem with buffer tanks (unless they have only 2 ports) is that you get mixing between flow and return, unless the pumps either side are balanced, or alternatively they are probably controlled, which is rarely the case.

This reduces the ft to emitters frequently by the deltaT across the emitters.  There is a 2-3% efficiency penalty for each degree which soon mounts up.  Also they make fault finding difficult and hide faults that should be fixed, which is why so many installers still fit them.  The more enlightened installers will tell you that they are unnecessary in almost all domestic situations.  It's worth asking why they fitted it and getting the answer in writing if you can.

 

This post was modified 1 day ago 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.


   
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(@davidnolan22)
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@sandman1600 

not a massive problem.  I've got a lot loss header that's a similar theme to a buffer and I get COPS (on Mel cloud measuring) over 5 in mild weather around 4 close to freezing. I've found having a separate secondary system, 5 pumps, 2 manifolds, 9 zones really tricky to work out what's going on as you only get data for the primary circuit. But after 12 months of tinkering I think I've got it working pretty well.   But fitting buffers is still very standard and lots of manufacotrs recommend them and I find installers just parrot that.  I'd like to take out my Header and run it open, but my installer has currently indicates that's not possible. 

 


   
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