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LG Therma V R32 Monobloc. Setup advice inc flow temperature & weather compensation

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(@tim441)
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Background info:

  • Grade 2 Listed building (90sq m) with modern extension (75sq m)
  • Oil c/h upgraded to LG Therma V R32 16kw Monobloc ASHP in 2020
  • 100l buffer tank + 300l h/w tank
  • standard LG RS3 controller
  • 27 solar pv panels + batteries
 
Old part:
  • Modernised but old stone walls, single glazed, insulated floor, thatched roof
  • u/f heating downstairs (pipes set for oil heating) & 3 zones
  • Radiators upstairs with TRVs (target temp cool say 17deg)
  • Digital Thermostat in main room (kitchen - used a lot - target temp 20 deg day). 
  • Standard thermostats for 2 other rooms (mostly unused - so maintain low temp only) (target temp cool say 15deg)
  • Standard programmer (2 way for radiators & u/f heating)
 
Modern Extension (2015)
  • Double glazed, insulated floor, insulated roof & walls
  • u/f heating (pipes set for oil heating) & 3 zones
  • single storey
  • Digital Thermostat in main room (lounge & used a lot)  (target day temp say 20deg)
  • Digital thermostats for 2 other rooms (mostly less used - so maintain low temp only)  (target day temp say 19deg)
  • Standard programmer (1 way for all u/f heating)
Usage
  • WFH - so assumed need heat all day 
  • Keep it running 24x7
  • trial & error on flow temps. Installer set at 50deg i think. Progressively reduced to current 37deg
  • flow temp at 37deg is sufficient - except in recent coldest snap
  • Using digital thermostats main living areas drop overnight 1 or 2deg. Depends on external temps. 
  • During mild Nov using typical 35kw daily
  • During Dec using typical 50kw daily
  • During cold snap using typical 70-75kw daily with peak day 90kw
Issues
  • AI is currently off. Should it be?
  • Assume "Seasonal Auto Temp" is therefore offering no weather compensation – please advise.
  • Can access installer menu but so far not changed anything
  • Any suggestions please? Happy to use trial & error
  • Particularly interested in other views on best flow temp and whether i should use some weather compensation?
  • Not deeply technical but can follow instructions or use common sense!
This topic was modified 1 year ago by Tim441

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


   
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(@tim441)
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Posts: 166
Topic starter  

should also mention that during cold snap the ashp seemed to perform well and provided most of our heating needs. We needed a boost sometimes and rather than increase flow temperature we used a convector heater for an hour or two and in the afternoons & evenings quite often used a woodburner. Wood burner was nice option for ambiance as well as boosting heat.

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


   
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(@derek-m)
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Posted by: @tim441

should also mention that during cold snap the ashp seemed to perform well and provided most of our heating needs. We needed a boost sometimes and rather than increase flow temperature we used a convector heater for an hour or two and in the afternoons & evenings quite often used a woodburner. Wood burner was nice option for ambiance as well as boosting heat.

I would suggest that you have a read through the manual and ensure that your system is set for weather compensation, then gradually adjust the settings so that the weather compensation curve matches your home's heat loss as close as possible. This should provide efficient operation.

 


   
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(@benseb)
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Posts: 105
 

You want to avoid the thermostats doing anything and keeping as many radiators etc open. 

So set them as say 30c and then adjust the WC until it keeps the room at your desired temp. If all the rooms gets too hot, turn the curve down. If just one room then turn the flow to that room down 

 

That way it’ll run low and slow rather than stop starting. 

250sqm house. 30kWh Sunsynk/Pylontech battery system. 14kWp solar. Ecodan 14kW. BMW iX.


   
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(@tim441)
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@derek-m thats easier said than done. 

The installer manual is unfathomable to me and the user manual is pretty useless also - unless one has a decent base understanding. Installers unfortunately don't seem to see it as part of the process to help with knowledge transfer.

I'm hoping that someone with direct knowledge of LG  Therma V controls can help with some pointers.

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


   
ReplyQuote
(@derek-m)
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Posted by: @tim441

@derek-m thats easier said than done. 

The installer manual is unfathomable to me and the user manual is pretty useless also - unless one has a decent base understanding. Installers unfortunately don't seem to see it as part of the process to help with knowledge transfer.

I'm hoping that someone with direct knowledge of LG  Therma V controls can help with some pointers.

I fully agree that the LG manual leaves a great deal to be desired.

I have attached a copy of the Installer Settings section of the manual, which you may or may not have. Read through the manual and raise any question for items about which you are uncertain.

 


   
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(@tim441)
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@derek-m many thanks. 

Currently I have "Heat" setting with flow temp 37deg and h/w 45 deg

The "Settings" are almost same as shown in your pdf

1. If I understand correctly I need to change "Heat" to "Auto"? That changes the flow temp to show "AI"

2. Looking through the Installer Settings I'm trying to understand the relevant ones for weather compensation and to set best efficiency. 

3. After "Screed Drying setting" there are 3 settings (not in pdf) that I guess may be relevant.. currently set as:

Outdoor Temp for Auto Mode
-4 Min   15 Max

Indoor Air Temp for Auto Mode
16 Min   21 Max

LWT for Auto Mode 
20 Min   65 Max

4. I'm not sure if I should simply change to Auto/AI as 1. above or should check/change anything else?

5. In the pdf after "Smart Grid(SG) setting it shows "Seasonal auto temp setting" and "Modbus Address"
But neither of these show in my "Settings" menu. Is that ok?

 

would it help if I post any other current settings?

Thanks!

 

 

 

 

 

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


   
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Mars
 Mars
(@editor)
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@bobbt9866 - with your LG expertise, is this something you could assist Tim with and point him in the right direction?

Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU

Follow our sustainability journey at My Home Farm: https://myhomefarm.co.uk


   
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(@derek-m)
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Posted by: @tim441

@derek-m many thanks. 

Currently I have "Heat" setting with flow temp 37deg and h/w 45 deg

The "Settings" are almost same as shown in your pdf

1. If I understand correctly I need to change "Heat" to "Auto"? That changes the flow temp to show "AI"

2. Looking through the Installer Settings I'm trying to understand the relevant ones for weather compensation and to set best efficiency. 

3. After "Screed Drying setting" there are 3 settings (not in pdf) that I guess may be relevant.. currently set as:

Outdoor Temp for Auto Mode
-4 Min   15 Max

Indoor Air Temp for Auto Mode
16 Min   21 Max

LWT for Auto Mode 
20 Min   65 Max

4. I'm not sure if I should simply change to Auto/AI as 1. above or should check/change anything else?

5. In the pdf after "Smart Grid(SG) setting it shows "Seasonal auto temp setting" and "Modbus Address"
But neither of these show in my "Settings" menu. Is that ok?

 

would it help if I post any other current settings?

Thanks!

The more I see of the LG controller and the manuals, the less I am impressed.

Make a note of the original settings should you decide to make any changes.

Going through the various parameters in order, these are the ones that I feel may be relevant.

Select Temperature Sensor, should be set to 'Water'.

Water Heating Set Temperature, this is the temperature range over which the warm water produced by the heat pump can be varied.

Heater Priority, set to 'Boost heater only ON'.

Heating Temperature Setting, set to 'Outlet'.

I am not certain if 'Seasonal auto temp' will appear in the list if the controller is set to Auto/AI mode, I suspect that you will have to give it a try. The instructions in the manual must rate as the worst ever produced and are about as clear as mud.

If anyone is unfortunate to have an LG system and has been able to decipher the LG code, I would welcome your assistance in setting weather compensation.

 


   
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(@hughf)
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Posts: 479
 

If you set the temperature sensor option to air+water, this will enable a blended mixture of load compensation and weather compensation. In other words, the LG controller will be the thermostat.

This is only relevant if the controller is in a habitable space.

There is a massive thread on buildhub about the Therma V. Well worth a read.

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.


   
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(@tim441)
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Topic starter  

thank you @derek-m & @hughf

I will post my changes & experiences here in case it helps others.... I welcome further input from anyone that has had experience with either flow temp changes or weather compensation in particular on LG Therma V. I will check buildhub and try to extract important suggestions here.

Select Temperature Sensor, was set to 'Water'. So no change so far. LG controller located in a bathroom outside airing cupboard. Bathroom has u/f heating and a towel rad so not sure if it will get meaningful air temps (unless relocated)?

Water Heating Set Temperature, this is currently set to 20 (no change so far). Any views? 

Heater Priority, Currently set to 'Main & Boost On'. Will review for potential change to 'Boost heater only ON'. But want to understand potential impact!

Heating Temperature Setting, was set to 'Outlet'. So no change

'Seasonal auto temp' does not seem to appear in the list if the controller is set to Auto/AI mode or Heat mode. So not sure if that's a documentation error or due to different software? But is probably important?!

This post was modified 1 year ago by Tim441

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


   
ReplyQuote
(@tim441)
Reputable Member Contributor
1426 kWhs
Joined: 2 years ago
Posts: 166
Topic starter  

Heater Priority, Currently set to 'Main & Boost On'. Will review for potential change to 'Boost heater only ON'. But want to understand potential impact!

Is this referring to Immersion Heater? So if I change to Boost only will the hot water heat more slowly (from ASHP) and not use immersion in normal usage? This would not be a problem for us as we are normally just 2 people at home and the tank is good size (300l).

Is Boost Only used just for the legionella cycle?

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


   
ReplyQuote
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