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Low loss header

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(@batalto)
Famed Member Member
3655 kWhs
Joined: 3 years ago
Posts: 1091
Topic starter  

Does anyone have the latest info from freedom on low loss headers? I asked my fitter to remove the current one and he won't do so because he said it would invalidate the warranty.

I'm sure someone said it's been updated in their documents to not be required anymore.

12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE


   
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(@batalto)
Famed Member Member
3655 kWhs
Joined: 3 years ago
Posts: 1091
Topic starter  

I've spoken with Freedom and after a really long and useful call (the guy has very helpful in talking over the system) he said the following things at the high level

  • There is no reason why you need a low loss header and they will warranty a system without one provided the proper calcs have been done and your system has been designed/confirmed to work without one
  • They say a low loss header loses you around 10%-15% efficiency 
  • They put them in (low loss headers) to ensure customers don't have issues through poor design from the trade
  • Weather compensation is set high as they expect the installer to have done the work to set the correct curve
  • Midea specify low loss headers in their documents so Freedom is just repeating the statement
  • Ideally you should run off the controller and not a thermostat
  • They do have an additional sensor to monitor return temps that allows the system to adjust weather compensation on the fly (or that was my understanding)

Now its down to me to see if I can get my fitter to actually make the changes and calculations needed. 

12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE


   
Kev M, ChickenBig, Derek M and 3 people reacted
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(@kev-m)
Famed Member Moderator
5562 kWhs
Joined: 3 years ago
Posts: 1299
 
Posted by: @batalto

I've spoken with Freedom and after a really long and useful call (the guy has very helpful in talking over the system) he said the following things at the high level

  • There is no reason why you need a low loss header and they will warranty a system without one provided the proper calcs have been done and your system has been designed/confirmed to work without one
  • They say a low loss header loses you around 10%-15% efficiency 
  • They put them in (low loss headers) to ensure customers don't have issues through poor design from the trade
  • Weather compensation is set high as they expect the installer to have done the work to set the correct curve
  • Midea specify low loss headers in their documents so Freedom is just repeating the statement
  • Ideally you should run off the controller and not a thermostat
  • They do have an additional sensor to monitor return temps that allows the system to adjust weather compensation on the fly (or that was my understanding)

Now its down to me to see if I can get my fitter to actually make the changes and calculations needed. 

10-15% is a lot of money at upcoming prices (I appreciate not so much for you personally!).  But sounds like good news. Maybe your guy could bypass the LLH but leave in place just in case?

This post was modified 2 years ago by Kev M

   
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(@batalto)
Famed Member Member
3655 kWhs
Joined: 3 years ago
Posts: 1091
Topic starter  

@kev-m speaking frankly I'm not sure my installer is up for it. He's more of a plumber by his own admission. I might need to call freedom and see if they can recommend an engineer Vs a technician.

12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE


   
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(@saenergy)
Trusted Member Member
105 kWhs
Expert
Joined: 3 years ago
Posts: 15
 

The low loss header (LLH) is typically used to ensure flow rates and reduce call outs due to restrictive conditions in retro fit setups.

whilst they do work, in practice there is a trade off as the secondary pump, the one which then becomes the heating circulator, has no modulating control from the heat pump.  A modern heat pump, such as the Midea, controls flow temp using a combination of fan speed, compressor duty and circulator flow rate.   It’s extremely efficient when used this way. 

When you separate the ASHP and house circulation this way, the only compensated flow is the primaries from the ASHP. 

ideally we wouldn’t use them.  In practice there are a number of issues. 

1- lack of maintenance leads to flow issues.  An LLH Reduces load and gives a low speed area of water in the vessel, this naturally aerates and drops dirt to the internal magnet.  Therefore extending the period between faults.  It’s a fix rather than a cure. 

2- retrofit plumbing can have a number of issues.  Unknown pipe routes.  Unknown sizing etc.  separating the flows means we don’t have to worry too much about that. 

3- the manual actually shows it installed.  Most installers will not go off piste and the manual is gospel and the word of the warranty gods.  Most of it is pure nonsense but it will cause a bun fight in the event of a claim. 

there are situations where an LLH is a must.  Micro bore setups will not generally allow the high flow rates needed for heat pumps and will constantly fault on flow.  LLH fixes that.

In an ideal world, we wouldn’t bother with separation at all.  If your plumbing system is good, then theoretically it will work fine.  It’s an acceptance of liability.  If you were asking me as an installer, I’d be ok with it, I’d just provision to retro fit later, so leave space in the pipework for the LLH and a pump.  Four lever valves to allow a section of pipe to be easily removed on the flow and return.  Probably install the auto bypass in that section as it can go when an LLH is used. 

hope some of this helps.

Internationally recognised award winning installer of heat pumps and stuff


   
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(@batalto)
Famed Member Member
3655 kWhs
Joined: 3 years ago
Posts: 1091
Topic starter  

@saenergy I have a feeling you are the person who has been recommended to me by Freedom to modify my system. I sent you an email yesterday (if you're that same SA energy they recommended)

12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE


   
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(@saenergy)
Trusted Member Member
105 kWhs
Expert
Joined: 3 years ago
Posts: 15
 

ah that is likely.  I’ll be in touch.  Been laid up with a broken back.  

Internationally recognised award winning installer of heat pumps and stuff


   
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(@batalto)
Famed Member Member
3655 kWhs
Joined: 3 years ago
Posts: 1091
Topic starter  

@saenergy that'll be you. The nice lady on the phone said you were at home because of an injury and were just doing emails etc - and clearly checking forums. Hope you make a speedy recovery. In the meantime happy to share any info you might need to understand my system/issues I am trying to fix.

12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE


   
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(@batalto)
Famed Member Member
3655 kWhs
Joined: 3 years ago
Posts: 1091
Topic starter  

@saenergy any idea when you might be able to come to make those system changes?

12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE


   
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(@sunandair)
Prominent Member Member
2545 kWhs
Joined: 2 years ago
Posts: 345
 

Posted by: @batalto

 any idea when you might be able to come to make those system changes?

 

hi @batalto I’m interested in what you did in the end. Did you manage to remove your low loss header? What was the layout you chose. I’m thinking of leaving the LLH in place and connect the returns through it and then bypass the two flows, connecting them together, with an air vent included.

 


   
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