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Grant 13kW Aerona3 - issues getting zones to temp

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(@crimson)
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Posted by: @heacol

@crimson Unfortunately unless you change the installation, anything you do will have little effect on the performance of the system. Heating systems are dynamic and change every minute of the day, Balance it now, with your system, and in 10 minuets it will be out again.

I am developing a Delta T controller which we will install on @admin 's system in a month or so. It will be commercially available shortly after that. This will help considerably improve the performance on units like yours as it will actively balance the flow rate to the demand, ensuring best performance.

 

Thanks @heacol, I can only keep pursuing the builders/plumbers on this project, I see you're based in Cumbria, don't suppose you'd ever venture out to Suffolk should we never get this resolved?

I've looked back at the heat calc for this project which states:

image

Don't suppose this is where I could hold it to the plumbers if this is the design max flow temp?  Or is that just referencing the heat pump?

 


   
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(@derek-m)
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Posted by: @crimson

Posted by: @heacol

@crimson Unfortunately unless you change the installation, anything you do will have little effect on the performance of the system. Heating systems are dynamic and change every minute of the day, Balance it now, with your system, and in 10 minuets it will be out again.

I am developing a Delta T controller which we will install on @admin 's system in a month or so. It will be commercially available shortly after that. This will help considerably improve the performance on units like yours as it will actively balance the flow rate to the demand, ensuring best performance.

 

Thanks @heacol, I can only keep pursuing the builders/plumbers on this project, I see you're based in Cumbria, don't suppose you'd ever venture out to Suffolk should we never get this resolved?

I've looked back at the heat calc for this project which states:

image

Don't suppose this is where I could hold it to the plumbers if this is the design max flow temp?  Or is that just referencing the heat pump?

 

From the information just provided, I suspect a 10kW heat pump would have been more than adequate.

As @heacol has indicated it will be impossible to balance the flow rates accurately, because the speed of the water pump within the heat pump varies with changing operating conditions, so unless the secondary water pump speed is also varied to match, then balanced flow rates will not be possible. The best that you can probably achieve is to try to ensure that the secondary flow rate is lower than the primary flow rate.

Probably the best solution would be to have the LLH, secondary water pump and possibly zone valves removed, along with installing a smaller capacity heat pump.

 


   
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(@derek-m)
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@crimson

The other important aspect to confirm is that the total capacity of the heat emitters is capable of emitting 7.86kW of thermal energy with a maximum water temperature of 40C.

I would suggest that you ask the installer and builder for a copy of the design calculations for your system.


   
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(@crimson)
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Posted by: @derek-m

@crimson

The other important aspect to confirm is that the total capacity of the heat emitters is capable of emitting 7.86kW of thermal energy with a maximum water temperature of 40C.

I would suggest that you ask the installer and builder for a copy of the design calculations for your system.

 

Hi Derek, I have the to hand, but not posting here as has address details, happy to DM you directly if useful?

I believe the calcs were done based on this, but I'm seeing potential issues now looking through some it based on factors such as floor type.

I think calcs were done assuming a D20 correction factor against rads.

 


   
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(@derek-m)
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@crimson

Please feel free to DM if you wish.


   
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@crimson

According to the heat loss calculations the design called for two K2 600mm x 1400mm radiators in both Living Room 1 and Living Room 2. Each of these radiators were sized to be able to provide 583W of thermal energy at a LWT of 40C, a RWT of 35C, giving a MWT (Mean Water Temperature) of 37.5C. The DT between MWT and IAT would therefore be 37.5C - 21C = 16.5C, not 20C.

The DT50 for each radiator was specified as 2464W.

According to the data for the actually installed Eskimo radiators (if I am looking at the correct model), the 200mm x 1694mm has a specified DT50 of 1540W and the 200mm x 963mm radiator has a DT50 of 880W.

Could you please confirm the model of Eskimo radiators that have actually been installed?


   
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(@crimson)
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Posted by: @derek-m

@crimson

According to the heat loss calculations the design called for two K2 600mm x 1400mm radiators in both Living Room 1 and Living Room 2. Each of these radiators were sized to be able to provide 583W of thermal energy at a LWT of 40C, a RWT of 35C, giving a MWT (Mean Water Temperature) of 37.5C. The DT between MWT and IAT would therefore be 37.5C - 21C = 16.5C, not 20C.

The DT50 for each radiator was specified as 2464W.

According to the data for the actually installed Eskimo radiators (if I am looking at the correct model), the 200mm x 1694mm has a specified DT50 of 1540W and the 200mm x 963mm radiator has a DT50 of 880W.

Could you please confirm the model of Eskimo radiators that have actually been installed?

 

hi Derek those are the ones installed. So essentially they were talking about D20 when really should have been talking about D15? And weren’t referring back to the proposed calcs, this could be where sizing has just gone terribly wrong. I think upstairs could be undersized too but as the temp requirement is more 18-19c not noticeable. Though that zone can effectively hit that temp with TRVs right down to 1

 


   
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(@derek-m)
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Posted by: @crimson

Posted by: @derek-m

@crimson

According to the heat loss calculations the design called for two K2 600mm x 1400mm radiators in both Living Room 1 and Living Room 2. Each of these radiators were sized to be able to provide 583W of thermal energy at a LWT of 40C, a RWT of 35C, giving a MWT (Mean Water Temperature) of 37.5C. The DT between MWT and IAT would therefore be 37.5C - 21C = 16.5C, not 20C.

The DT50 for each radiator was specified as 2464W.

According to the data for the actually installed Eskimo radiators (if I am looking at the correct model), the 200mm x 1694mm has a specified DT50 of 1540W and the 200mm x 963mm radiator has a DT50 of 880W.

Could you please confirm the model of Eskimo radiators that have actually been installed?

 

hi Derek those are the ones installed. So essentially they were talking about D20 when really should have been talking about D15? And weren’t referring back to the proposed calcs, this could be where sizing has just gone terribly wrong. I think upstairs could be undersized too but as the temp requirement is more 18-19c not noticeable. Though that zone can effectively hit that temp with TRVs right down to 1

 

Unless you instigated the changes, I would certainly question why the originally specified radiators were changed to the ones actually installed.

 


   
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(@crimson)
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Posted by: @derek-m

Posted by: @crimson

Posted by: @derek-m

@crimson

According to the heat loss calculations the design called for two K2 600mm x 1400mm radiators in both Living Room 1 and Living Room 2. Each of these radiators were sized to be able to provide 583W of thermal energy at a LWT of 40C, a RWT of 35C, giving a MWT (Mean Water Temperature) of 37.5C. The DT between MWT and IAT would therefore be 37.5C - 21C = 16.5C, not 20C.

The DT50 for each radiator was specified as 2464W.

According to the data for the actually installed Eskimo radiators (if I am looking at the correct model), the 200mm x 1694mm has a specified DT50 of 1540W and the 200mm x 963mm radiator has a DT50 of 880W.

Could you please confirm the model of Eskimo radiators that have actually been installed?

 

hi Derek those are the ones installed. So essentially they were talking about D20 when really should have been talking about D15? And weren’t referring back to the proposed calcs, this could be where sizing has just gone terribly wrong. I think upstairs could be undersized too but as the temp requirement is more 18-19c not noticeable. Though that zone can effectively hit that temp with TRVs right down to 1

 

Unless you instigated the changes, I would certainly question why the originally specified radiators were changed to the ones actually installed.

 

 

hi Derek, I think the issue was what they suggested in these calcs couldn’t fit and they started going on about adding 2 tall rads with shorter ones (600mm height wouldn’t fit under the windows) and wouldn’t come with other options so I found the Eskimo ones based on Delta 20. However upon asking if those would work they said they would. We even asked if could go wider in one of the rooms. Am sure this will be a circular blame game though. Frustratingly the builder said he had the heat specialist check sizing but I’m not certain he did.

 

looking at my vlookup sheet of Eskimo rads for Living 2 doubling the height from 200 to 400 would give 4504W against the adjust delta 16 requirement of 2979W for living 2 (Eskimo correction of 0.33 for delta 16). Even just doubling one would meet it but for balance both should do it.

 

Ill report this back and see what everyone says

This post was modified 3 months ago by Crimson

   
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(@derek-m)
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Posted by: @crimson

Posted by: @derek-m

Posted by: @crimson

Posted by: @derek-m

@crimson

According to the heat loss calculations the design called for two K2 600mm x 1400mm radiators in both Living Room 1 and Living Room 2. Each of these radiators were sized to be able to provide 583W of thermal energy at a LWT of 40C, a RWT of 35C, giving a MWT (Mean Water Temperature) of 37.5C. The DT between MWT and IAT would therefore be 37.5C - 21C = 16.5C, not 20C.

The DT50 for each radiator was specified as 2464W.

According to the data for the actually installed Eskimo radiators (if I am looking at the correct model), the 200mm x 1694mm has a specified DT50 of 1540W and the 200mm x 963mm radiator has a DT50 of 880W.

Could you please confirm the model of Eskimo radiators that have actually been installed?

 

hi Derek those are the ones installed. So essentially they were talking about D20 when really should have been talking about D15? And weren’t referring back to the proposed calcs, this could be where sizing has just gone terribly wrong. I think upstairs could be undersized too but as the temp requirement is more 18-19c not noticeable. Though that zone can effectively hit that temp with TRVs right down to 1

 

Unless you instigated the changes, I would certainly question why the originally specified radiators were changed to the ones actually installed.

 

 

hi Derek, I think the issue was what they suggested in these calcs couldn’t fit and they started going on about adding 2 tall rads with shorter ones (600mm height wouldn’t fit under the windows) and wouldn’t come with other options so I found the Eskimo ones based on Delta 20. However upon asking if those would work they said they would. We even asked if could go wider in one of the rooms. Am sure this will be a circular blame game though. Frustratingly the builder said he had the heat specialist check sizing but I’m not certain he did.

 

looking at my vlookup sheet of Eskimo rads for Living 2 doubling the height from 200 to 400 would give 4504W against the adjust delta 16 requirement of 2979W for living 2 (Eskimo correction of 0.33 for delta 16). Even just doubling one would meet it but for balance both should do it.

 

Ill report this back and see what everyone says

It bodes the question "if 600mm high radiators will not fit, why were they specified"?

Will 400mm high radiators fit?

 


   
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(@crimson)
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This was the battle I had I think in June last year, they were just useless and I asked if we could get other plumbers but was reassured (incorrectly it seems as since they’ve parted ways).

400 will fit but I suspect for the pipe work slightly tight. May mean skirting boards have to come off again (they got pipe centres wrong even though I said why does the room with 2 equal width rads look like one wider apart than other).

Doubling heights in living room could mean no decorative work potentially or minimal. But hallway would need to double in width which would mean decorative work.

I’d see this however as them not checking sizing before commissioning the system. And also why are they bumping the temp up beyond the design is beyond me too.

This post was modified 3 months ago by Mars

   
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(@derek-m)
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@crimson

The quantity of thermal energy that can be emitted by a radiator is dependent upon its size (emitting area), the MWT and the IAT. As the IAT increases the quantity of emitted thermal energy actually reduces for a given MWT. Increasing the MWT will of course increase the emitted thermal energy at a given IAT, which in turn should cause the IAT to increase until balance is obtained.

The loading on a heat pump is therefore dependent upon the quantity of thermal energy that can be absorbed and emitted, which is why the RWT increases as the heating demand reduces. The heat pump therefore reduces its output by throttling back, or stopping when it cannot go any lower.


   
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