Avoid the Heat Pump Villain: Why Low-Loss Headers and Buffers Can Sabotage Your Heat Pump's Efficiency
@jamespa measuring with clamp-on heating pipe thermometer? I see ebay/amazon has them around £6 or £7 .. Good enough?
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
Posted by: @tim441@jamespa measuring with clamp-on heating pipe thermometer? I see ebay/amazon has them around £6 or £7 .. Good enough?
I believe so, we are looking for difference so as long as you can clamp consistently then it doesn't matter if the figure isn't perfect.
I stress there is absolutely no need to do this unless you want to.
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.
Borrowed a clamp on thermometer.
Buffer tank: PAW-BTANK50L-2 buffer tank
Only 48l
According to ashp controls
leaving temp 33deg
Return 31 deg
Arr from ashp BT 34.4flow
Leave BT 34.1 flow
Arr from house BT 33.2 return
Leave 33.8 BT return
I suspect not great test right now... as mild... so not working hard
Will be better to check on cold morning.. perhaps.
Will report again once more results
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
@tim441 the other thing to “check” is where the respective flow and returns are to see if your buffer has minimal distortion. Ideally, it’s plumbed like this:
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Logically the electronic motorised valve.. I think... stops buffer being used when heating DHW/hot water tank. So will be on flow to BT?
With the pump on right on flow from BT?
Tap at bottom right ... return to BT?
So same as your diagram. but I'll try the thermometer a few times in different scenarios
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
Posted by: @tim441Logically the electronic motorised valve.. I think... stops buffer being used when heating DHW/hot water tank. So will be on flow to BT?
Is it a 2 way valve or a 3 way diverter valve. Normally the (3 way) diverter valve is the only motorised valve needed.
As you say taking some temperature measurements when its working harder would be good, but your initial ones are encouraging.
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.
@jamespa it's 3 way
Listed Grade 2 building with large modern extension.
LG Therma V 16kw ASHP
Underfloor heating + Rads
8kw pv solar
3 x 8.2kw GivEnergy batteries
1 x GivEnergy Gen1 hybrid 5.0kw inverter
Manual changeover EPS
MG4 EV
Posted by: @tim441@jamespa it's 3 way
I presume the diverter valve then, which would make sense. As you say you would expect this to be on the inlet to the BT
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.
Hi, so if I wanted to make my system more efficient, It's open loop 28/22/15mm ,all rads,run via a Homely is it possible to remove the buffer tank but still comply with 7-year LG warranty requiring hydraulic separation. Thanks
@potatoman can you share LG's official documentation that explicitly requires hydraulic separation to maintain the 7-year warranty?
If you've got that document, it would be extremely valuable to see it.
Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb
Subscribe and follow our Homeowners’ Q&A heat pump podcast
To me that reads as 'Hydraulic separation optional but if present covered for 7 years if you take out the extended warranty', as opposed to 'Hydraulic separation mandatory'. The very last line in the table (mag filter) would seem to confirm this.
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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