Panasonic Aquarea - H12 error

Hi,

I have a Panasonic Aquarea WH-SDF16C9E8 installed for underfloor heating and it's been running fine for 4 years, but the last 2 months it is throwing H12 error (indoor-outdoor capacity umatched). Strange thing is that the H/T can go on working fine for 5 days and then it could start throwing the error twice a day, and then again after three or four occurrences run again for 5 days.

Any idea what I can do to find the source of this error? Could this be a communication error or that one of the units (indoor/outdoor) is drawing more power for some reason (e.g. water pump is drawing more power because underfloor needs flushing or whatever) triggering the error?

Installer says that's it's probably the outdoor PCB and I should get it replaced.
Thanks!

have good luck and a lot of spared parts to change....by trial and error.....

try first the sensors and then proceed with more expensive parts as pcb and the like...

Hi Greek Engineers

My suggestion is to contact Panasonic in your country and get a service manual sent to you.

But having said that all it says is check indoor \ outdoor models are compatible.

If they are compatible models then change the indoor and main outdoor PCBs.

Cheers

Loops

IN GREECE even the central dealer may advice you to perform by trial and error!
no one knows or takes the responsibility to change a part and be 100% sure he found the error.

I downloaded the service manual and it says that in a fault event first carry out measurements of pressure, electric current, temperature and water flow. If everything comes out fine than you should check with the error codes and troubleshooting actions. So trial and error is not the first option given here.

I cleaned the filter that's installed before the water inlet, there was a lot of dirt trapped inside and some sort of glue on the mesh (brass pipe glue maybe?). I suppose that this was putting stress on the water pump and probably slowing down the water flow. So far that seems to have resolved the issue, it's been running fine without any errors for a week.

The weather these days has been really good here, so I was wondering if the error is also somehow connected to cold conditions. Low or too high gas pressure maybe ?

In any case I will bring a technician in to check the refrigeration cycle, pump-down the system and measure the refrigerant.