Stone foundation heat pump experiences?

Hello everyone,

maybe someone here can help me from experience.

I want to make a foundation myself for our air heat pump at the beginning of next week. In the foundation plan from the company Vaillant, it says to fill about 80 cm of the approximately 1 m deep foundation with permeable coarse gravel and the remaining 20 cm with gravel. The pump will later be placed on 2 strip foundations. The problem now is that my heating engineer is on a two-week company vacation and is not reachable... But I have to finish the foundation because the paving work will continue the week after next and everything should then be neatly integrated.

My question:

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

Can't you just use washed Rhine gravel or something similar in 16 - 32 mm and fill the entire foundation with it? A 100 mm KG pipe about 80 cm long will also be installed in the foundation so that the condensate can drain away.

Has anyone done this before?

I would appreciate feedback.

Regards

Heiko

Where do you direct the condensate? If it is gone, why bother with the drainage gravel?

Has anyone done this before?

I simply set the strip foundation (on gravel) (approx. 80 cm screed concrete foundation). Then placed the heat pumps on the supports shown in the picture. This is recommended, for example, by Panasonic. Not such an effort as you have it.


Addendum: Condensate water just drains away, to the left of the foundations is the driveway with a drain.

The condensate should be able to run directly downwards through the KG pipe into the frost-free zone. This is stated in the foundation plan for the Arotherm Plus from Vaillant. I have agreed with the heating installer that I want to do this myself. Of course, I want to do it as prescribed so that if there are any problems later, it won't be said that it was done incorrectly. That is how it is described, but I don't know what to do about the coarse gravel....

I also saw that in the foundation plan like that ;)

But no one does it like that... Everyone only does strips on the left and right and then dowels on top
Distance to the wall 30cm and that's it

I specially looked at 5 houses in the area with [vaillant pumps] (they are getting one too)

and then dowelled onto it

Would advise you to decouple. Prevents noise.