ᐅ Experiences with stone foundations and heat pumps?

Hello everyone,

perhaps someone here can help me based on their experience.

I want to build a foundation next week myself for our air-source heat pump. In the foundation plan from the company Vaillant, it says to fill about 80 cm (31.5 inches) of the approximately 1 m (3.3 feet) deep foundation with permeable coarse gravel, and the remaining 20 cm (7.9 inches) with crushed stone. The pump will later be installed on two strip foundations.

The problem is that my heating technician is on a two-week company vacation and cannot be reached... But I have to finish the foundation because the paving work will continue the week after next, and everything should be properly integrated then.

My question is:

What exactly is meant by permeable coarse gravel? The building materials supplier says the term is too general...

Could I simply use washed river gravel or similar, sized 16 - 32 mm (0.6 - 1.3 inches), and fill the entire foundation with that? There will still be a 100 mm (4 inch) drainage pipe about 80 cm (31.5 inches) long in the foundation to drain the condensate.

Has anyone done this before?

I would appreciate any feedback.

Regards

Heiko

Where do you direct the condensation water?
If it’s flowing away, why bother with the drainage gravel?

Heiko2022 schrieb:

Has anyone done this before?

I simply poured a strip footing (on gravel) about 80cm (31.5 inches) thick made of screed concrete. Then I placed the heat pumps on the supports shown in the picture. This is also recommended by Panasonic, for example. It’s not as complicated as you make it out to be.

Additional note: Condensation water drains away naturally; there is a driveway with a drainage channel to the left of the footings.

The condensate water should be able to flow directly down through the underground pipe into the frost-free zone. This is what the foundation plan for the Arotherm Plus by Vaillant specifies. I have agreed with the heating engineer that I will handle this myself. Of course, I want to do it exactly as required, so that if there are any issues later on, it won’t be said that it wasn’t done correctly. That’s how it is described, but I’m not sure what to do about the coarse gravel…

I also saw that on the foundation plan 😉

But nobody does it that way... Everyone just uses strips on the left and right and then attaches the components there.
Distance to the wall is 30 cm (12 inches) and that's it.

I specifically looked at 5 houses in the area with Vaillant pumps (we're getting one too).

Reggert schrieb:

and then dowelled onto that

I would recommend using decoupling. It helps prevent noise.