ASHP concrete base

[Wagas]

Hi, my installer wants me to put down a concrete base for the ASHP. I'd rather it goes on the paving slabs that will form the paths and patio but he seems reluctant. Do you guys all have your ASHP's on a concrete base?

[Jeremy Harris]

The spec for our ASHP gave the dimensions for the concrete base, with two options, either two cast concrete piers or one larger, single, one.  It so happened that the dimensions of each pier in the two pier option was very close to the size of a block laid on it's side, so the base for ours is made up from two piers, each consisting of two blocks laid on their side, bedded on a concrete foundation.

 

I don't think you'd be able to secure it to paving slabs for a couple of reasons.  Firstly, the ASHP really needs to be raised above ground level a bit, both to allow easy access to the condensate drain connection underneath (this is easier with the thing on two piers) and also because it may tend to be noisier if mounted on slabs (although fitting a rubber anti-vibration mount under each leg might make that work OK).

 

I find that, at this time of the year, the ASHP tends to draw dead leaves in around it, so having a decent gap underneath it to sweep this area clear is handy.  If doing it again I think I would opt to raise the ASHP up a bit more, maybe using three, or even four, blocks per side,  mainly to make cleaning around it easier.

[ProDave]

Mine is on two 60cm square slabs, the 50mm thick heavy ones.  

 

It weighs less than an oil fired boiler and I see plenty of outside oil boilers doing just fine on a couple of slabs.

 

It sits on four anti vibration mounts.  Drill carefully and fit a suitable rawl plug and you can fix the anti vibration feet to the slab.

 

 

There is no specific condensation drain point on ours, it just drips condensation from various holes under the fan area.  In this case it is not part of a path to walk on, and the condensate just disperses onto the ground.

[joe90]

Mine is on a block made of concrete blocks on their side (6) then cast concrete around them. Didn’t use vibration pads and it’s very quiet.

 

Edited November 17, 2019 by joe90

[ragg987]

You need to ensure condensate can drain. In the winter this will freeze over, on a patio it would be asking for trouble.

[joe90]

8 minutes ago, ragg987 said:

You need to ensure condensate can drain. In the winter this will freeze over, on a patio it would be asking for trouble.

 

+1, my “mount” has gravel behind it to absorb condensate, and it’s more than I thought.