ᐅ Water softening and filling system for heat pump

Hello everyone,

I’m currently frustrated with the HVAC trade.
To begin with, a brine heat pump with around 6kW power will be installed, of course with underfloor heating.
I have already moved past the topic of the buffer tank with an HVAC company while preparing the scope of work. Especially after I made it clear that the heat pump will run on household electricity, so there will be no restricted operation times, they gave up on trying to install a 46-liter (12-gallon) buffer tank for the heating system. Phew.

However, we’re still stuck on the water softening. That’s another “nice extra” they always install (and the costs are not itemized separately). I’m having a hard time finding reliable sources regarding the benefits or even the necessity of such a system. The water hardness in the building area is 12.3° dH.
Is a water softening system really needed for the heating system?

In addition, he wants to install an automatic filling system for the heating water. Does that make sense? I imagine the amounts that need refilling are small and doing this manually once a year (how exactly does that work – my current gas boiler just has a hose and a valve, and that’s it) wouldn’t be a big deal...

I’m a bit stuck here.

I assume you are referring to the softening of the water during the initial filling. This is required by VDI 2035 and should also apply in your case. However, in my opinion, an additional treatment system for refilling would be quite excessive.

I consider an automatic filling system unnecessary in single-family home construction. I agree with you on that. Regarding water softening, please refer to the previous speaker. Please clarify what they mean. Possibly they are not expressing themselves clearly, or you may be too suspicious of them. Karsten

I also think the water needs to be treated. However, I would have expected that for this one-time process, someone would come by with a mobile system, fill it up, and then leave. I’ve since looked it up and found that there are water softener cartridge systems for €150-200 that can soften 4-6 cubic meters of water to below 0.1° dH before the resin needs to be replaced. Maybe it’s something like that. That would still be acceptable if it means avoiding the costs of using a mobile softening/desalination system.

Maybe the filling system is just for convenience? I have no idea.

But thanks already for your feedback.

So, a clear plastic cartridge is also visible in our utility room. And you can believe me when I say that I used only standard components and nothing else. Karsten

We also have a water softening system for our heat pump (unfortunately only for the heating system and not for the drinking water [emoji51]).
This was used to fill the system, and I can refill it if needed.
It was included in the “heat pump” package from our general contractor...