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@potatoman Hi Potato, just contact LG and ask them, they will confirm if it will effect the warranty or not, in my experience the whole buffer no buffer thing comes from manufacturers designing them in on their schematics, if you look in most installation manuals they have them drawn in on most designs. I think there is an element of safety for the manufacturer to design them in as then all the manufacturer needs to worry about for their warranty is the buffer and minimum volume / flow is correct and is available, nothing much the house design side can then cause damage to the ASHP.
In my view check with them and don't void the warranty on this brand as they are known for compressors and evaporator fan issues, good news is if there are any issues with the actual ASHP an LG engineer will attend to fit the parts under warranty.
AAC Group Ltd covering the Kent Area for design, supply and installation of ASHP systems, service and maintenance, diagnostics and repairs.
@bobbt9866, can you please give us some insights on the 7 year warranty being connected to an LG heat pump requiring some form of hydraulic separation?
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Posted by: @ashp-bobbain my experience the whole buffer no buffer thing comes from manufacturers designing them in on their schematics,
I have the same impression. They sometimes design other things in too and don't make it clear whether its because they are needed or just illustrative to show how a system could work and where to put component X if it is included. It seems to me that its convenient for installers who want to put buffers in not to know which!
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.
Posted by: @ashp-bobbaHi Potato, just contact LG and ask them, they will confirm if it will effect the warranty or not,
I would love to hear the outcome of this phone call. If they're anything like Samsung, good luck!
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@potatoman Bob (who I refer to as Mr. LG) sent me some docs (which I've attached) along with the following explanation: "The 7 -year warranty is not given to everyone, but the documents drawn up by LG show buffer vessels as being installed and accepted. The warranty only applies to the units themselves and not the installation of which the buffer vessel is part. So, they would not specifically refer to it in warranty paperwork."
The attached docs could prove useful.
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@editor Perhaps I may be a sceptic but… It rather suggests to me that they mean the buffer tank and its’ installation is not covered by the warranty. That is a different kettle of fish with regards to whether the buffer tank is a required component to comply with the warranty requirements I think? Regards, Toodles.
Toodles, heats his home with cold draughts and cooks food with magnets.
@editor Thanks for the information, I had an interesting phone call with Unitherm Heating Systems today, they seem involved with the verification process of the LG 7-year warranty process, for my installer at least. They said, to get the 7-year warranty the installer has to undergo extra LG training and among other things submit photograph evidence of hydraulic separation, either a buffer tank or a volumiser and a LLH. This information has to be sent to Unitherm Heating Systems via the installer, once they have vetted the information it is sent to LG and then if all is correct a 7-year certificate is issued from LG to the homeowner.
I did ask about removing the buffer after I received the 7-year certificate, and they firmly said if there was a problem with the heat pump and the installer found you had removed the buffer tank, regardless of what the problem was on the heat pump there would be no warranty as the buffer tank "protects " the heat pump in numerous ways.
So unfortunately It's going to be no buffer tank for me, I just hope other manufactures are more accommodating, but also people who recommend the removal of the buffer tank on efficiency savings that can be made should also urge caution and get people to check their warranty conditions first .
Posted by: @potatomanpeople who recommend the removal of the buffer tank on efficiency savings that can be made should also urge caution and get people to check their warranty conditions first .
Agreed
However if the above is the official lg position it's a good argument in future to avoid lg, which is disappointing. I wonder if their quoted performance takes into account a typical buffer tank as installed. Oh, wait a minute, I think I can guess.
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.
@potatoman there’s also the option of a three port buffer, which limits distortion. Still considered hydraulic separation.
🔥 Britain’s Heat Pump Shitshow
How Installing a Heating System Became a National Nervous Breakdown
Free UK shipping.
📗 Heat Pumps Explained
A Jargon-Free Guide for Homeowners
Rewritten and updated for 2027
📘 From Zero to Heat Pump Hero
🛠️ Bodge Buster
New to heat pumps?
Take the Heat Pump Fundamentals course and use INTRO50 at checkout for 50% off.
Posted by: @potatoman@editor Thanks for the information, I had an interesting phone call with Unitherm Heating Systems today, they seem involved with the verification process of the LG 7-year warranty process, for my installer at least. They said, to get the 7-year warranty the installer has to undergo extra LG training and among other things submit photograph evidence of hydraulic separation, either a buffer tank or a volumiser and a LLH. This information has to be sent to Unitherm Heating Systems via the installer, once they have vetted the information it is sent to LG and then if all is correct a 7-year certificate is issued from LG to the homeowner.
I did ask about removing the buffer after I received the 7-year certificate, and they firmly said if there was a problem with the heat pump and the installer found you had removed the buffer tank, regardless of what the problem was on the heat pump there would be no warranty as the buffer tank "protects " the heat pump in numerous ways.
they do allow a volumiser to be used, so the obvious question is could a 4 port buffer be configured as a volumiser and stay in warranty?
2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with SCOP >4) open system operating on WC
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