Panasonic Air Source Heat Pump

[PeterW]

TBH that is my thoughts on all of these as you can stick an immersion in the buffer and get a backup if the ASHP fails or if you want a dump load for a PV array. For the sake of £2-300 it does seem like the logical solution, but in this instance the OP is referring to, the installation is authorised and as per the MIs so Panasonic need to cough up and fix it. 

[Rohan]

On 14/12/2020 at 22:29, PeterW said:

So in the MIs it states the following :

 

 

Go back to Panasonic, quote their own MIs

and say this did not require a buffer as over 50 litres. Give them the exact reference above and then ask them when they would like to send their engineer .... 

The problem I am having is who is telling the truth. Panasonic say that a buffer tank should be fitted as part of the installation requirements. The installer is saying on his commissioning paperwork that there are 50ltrs water volume so doesn't require one. As an ordinary householder how do I know what is required. He says that he has fitted over 300 heat pumps with no buffer tanks. I am know faced with a bill to put this right by another installer.

[SteamyTea]

9 minutes ago, Rohan said:

The problem I am having is who is telling the truth

Let's tackle the problem from another direction.

 

What is the power range of your heat pump? i.e. 3 to 12 kW

What is the heat load range? 4 to 7 kW

 

Then it should be easy to work out  if a buffer is needed.

[jack]

3 hours ago, Rohan said:

The problem I am having is who is telling the truth. Panasonic say that a buffer tank should be fitted as part of the installation requirements. The installer is saying on his commissioning paperwork that there are 50ltrs water volume so doesn't require one. As an ordinary householder how do I know what is required. He says that he has fitted over 300 heat pumps with no buffer tanks. I am know faced with a bill to put this right by another installer.

 

Can't you figure out how much the volume of your system is? I assume you have an UFH heating design somewhere, telling you how many metres of UFH loops you have. You can also estimate the volume of pipework between the manifold and the ASHP.

 

Assuming all that amounts to at least 50L, the installer situation becomes irrelevant, because you have it in writing in Panasonic's own manual that a buffer tank is only needed if the volume is less than that. What they say verbally is irrelevant given that it appears to contradict their own written instructions.

[Paul Birley]

Can i just query if this issue was ever solved? I have exactly the same issue with my Panasonic unit. A H65 error whenever the external unit is working at 0 Deg C or below outside. It is definitely having an issue defrosting / deicing itself. I don't have a buffer vessel either an if I did, i don't see why this would make it better. Any help you could offer would be appreciated. 

[Marvin]

Hopefully @Rohan will be able to help.

On 22/12/2020 at 17:42, jack said:

Assuming all that amounts to at least 50L, the installer situation becomes irrelevant, because you have it in writing in Panasonic's own manual that a buffer tank is only needed if the volume is less than that. What they say verbally is irrelevant given that it appears to contradict their own written instructions.

Assuming this was not updated information. I would check with the manufacturer for the latest.

[ReedRichards]

2 hours ago, Paul Birley said:

... I don't have a buffer vessel either an if I did, i don't see why this would make it better. 

 

Your heat pump needs a heater or a heat source to defrost.  So an easy option is to use the warm water in the buffer vessel as the heat source.

[Paul Birley]

Many thanks for the replies, I am struggling for space to fit a buffer vessel, I wondered if anyone had experienced installing one and if so, what size they went with and if they found that it worked better as a result of installing it. 

[JohnMo]

1 hour ago, Paul Birley said:

I am struggling for space to fit a buffer vessel

 

Grant do a LLH, volumiser with integrated immersion, could be made to fit any heat pump.  Looks really compact.

 

https://www.grantuk.com/about/news/heat-pump-and-low-loss-header-are-a-winning-combination/

 

They also do an external mounted volumiser.

 

Both could be made to fit other heat pumps

 

 

 

 

grant-combined-volumiser-low-loss-header-installer-uk-doc-0184-rev-1-0-november-2022 (1).pdf grant-external-volumiser-installer-uk-doc-0183-rev-1-0-november-2022.pdf

[Paul Birley]

Cheers JohnMo, that's really helpful. Appreciate the help.