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Was driving home this evening when I got stuck in a jam on M25, as I was musing out of the window I noticed an ASHP on a farm building and observed the cable tray running from it to the building which, from where I was, looked crowded. It struck me that we have not made provision for the ASHP connections to the new house as yet and that I should get this aspect of the scheme into my head and onto some drawings.

 

It looks like you need to get two well insulated water pipes, inlet and return, one condense drain, one power cable and probably a control cable, which I guess might be CAT6 or something simpler. A couple of thoughts struck me:

 

  1. Is there any limit to the length of the water pipes?
  2. Is it sensible to put them, the water pipes, into the slab, insulated, or run them outside the building. (I think that things which look like an after thought, such as pipes outside buildings should be designed out if possible)
  3. Can the condense drain run into the soak away or must it be piped to the sewer?

 

Any thoughts anyone.

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Ref No.1 The Samsung manual mentions a recommended maximum run of 25m but I would imagine the advice might differ by make/model.

 

Ref No.2. I think it's @jack that has put his flow and return into an eps channel in the slab which is definitely a great idea. We couldn't do it easily due to our split level so in the end went for a pre-insulated pipe set which enters the slab from outside and runs to the edge of the building below the outside finished level. It was expensive and HUGE and very difficult to get a bend radius on. 

http://www.ebay.co.uk/itm/PRE-INSULATED-UNDERGROUND-INSULATED-PIPE-KIT-DUO-TWIN-PIPE-32mm-/112440664851

We've run a 3 core SWA and 2 CAT5 to the same location.

 

Ref No.3 The Samsung unit we looked at just said that you should have a permeable area below the ashp that the condensation can drain into. 

 

Hope that helps

Edited by Barney12

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1. I think the max pipe length is likely to be manufacture specific primarily based on the pump capacity.

2. We have pre-insulated pipes set into the slab, so no visible nasties. We have also run a couple of Cat5 and a couple of 3 core to the location.

3. No idea what the correct answer  is but ours will soak away directly into the sandy soil below the ASHP.

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Check with the supplier as when you go up past 6kw IIRC some require you going with 28mm not 22mm pipe. 

 

I'm about to move ours as it's caught me out as I forgot the pipes when we did the slab and there is no easy or elegant way to get pipework to the unit without heading up into attic spaces etc or running it in skirting boxes which is my other option. 

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FWIW, I've found that the pump in our re-badged Carrier is a standard variable speed circulating pump.  Our pipe runs are short, less than a metre of 22mm copper, plus 900mm 19mm bore flexible pipes at the ASHP itself.  I had to turn the pump in the ASHP down to its lowest setting, as the flow was far too powerful with it on setting 3.

 

Given that the pump looks to be a standard unit, it may well be possible to substitute a larger one if needed.  The only things inside the ASHP on the water side, apart from the pump, are a standard looking plate heat exchanger, a tiny expansion vessel, a drain cock and an air vent.  All except the plate heat exchanger could be removed and replaced pretty easily, I think.

Edited by JSHarris

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You're lucky @JSHarris - I need to put a pump into ours but the current plan is to get another Wilo like the one on the Wunda manifold as they are near silent. 

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