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Ecodan - optimal external installation?

rhh2348 · 2024-02-03T11:21:25Z

Hello all, First time post, been a lurker for a while. Looking to understand best (Mitsubishi-approved) installation practices to minimise noise (heard both externally, and currently internally!) and maximise efficiency/performance of a year-old Ecodan PUZ-WM60VAA in a modern house. Have had a search around the site and can't find anything similar; if there is, please signpost me to it and I'll delete this post. Our external unit sits c. 300mm in front of a house wall with the flow and return pipes snaking to a length of c. 450mm behind it before entering the building. With the attached diagram in mind (found from clicking the 'Air Source Heat Pump Diagram' button on ...from the wall there is the foam-like (I think it's called Class O) insulation over the copper pipes to the isolator levers maybe 60mm along, then more Class O secured by cable ties over copper piping that bends down at 90deg then again to create a square 'U' before the second half of the pipework is copper pipe with a different shiny cover insulation that then goes over (not attached to) the flexible hoses to the back of the unit. I can't see any anti-freeze valves or full bore ball valves. The unit is mounted on 600mm rubber feet that sit on a concrete base. I don't know if they are bolted to the base or not (there seems some movement when the top edge is pushed). Rain collects to one side on the top so I assume it isn't level. My initial challenge points are around the length/configuration of the pipework between the wall and unit - I've read shorter runs create vibrations that can also travel along the internal pipework the unit should be level/straight in all directions - for balance / to ensure the blades turn optimally / minimise noise downwards from the feet - Mitsubishi's installation manual says to bolt the feet to concrete with a maximum of 30mm exposed out of the concrete. I note they do list the feet as an accessory (as 'anti-vibration mounts', and separately 'anti-vibration fix-it-foot' optionally with a slab), along with Anti-freeze! I'm considering replacing the pipework between the isolators and flexihoses so it is longer and straighter (and probably secured by wall-mounted rubber brackets). Is there an optimised run/length? This means I'd create a new (level) base alongside existing - whether a slab or two concrete plinths, with the rubber feet possibly bolted to it/them. Also wondered if there is an optimal unit height, relative to the pipework runs from the house? Grateful for people's critique / thoughts / suggestions on my thinking, anything I've missed, and other possible optimisations. Thanks in advance.

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HarriUp

(@harriup)

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13/02/2024 2:00 am

I think this notion of an 'optimal' install is something of a chimera. Every installation is different, and the majority of forum users have experience of just the one installation. From what you have said (though images are worth a thousand words) your installation seems to be fine, the installers haven't done anything stupid.

If you are having vibration issues at the heat pump then it might be an equipment issue rather than a pipework issue. I have noise inside introduced by the circulation pumps, but only small amounts of occasional mechanical noise and the sound of the air being moved from the outside unit. The units weigh around 100kg so you wouldn't want any slight vibration to be converted into sound or transmitted to the rigid, fixed pipework, but they aren't going to move around like washing machines.

You ask a few questions:

28mm pipework should run as far as you can take it into the house - you need volume of water in the system to cover defrosts.

You protect the outside pipework and the pump either by having glycol so the water can just sit at very cold temperatures, or you circulate the warm water in the pipes to keep the outside parts from freezing – the anti-freeze valves are a fail-safe should you be unable to power the water circulation. You would not want to be dumping glycol.

Full bore valves are isolating valves...

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HughF

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13/02/2024 8:17 am

I’d consider my system to be installed quite optimally… I have one anti freeze valve, no flexis, and over 20m of buried primary pipework.

I also don’t have any hydraulic separation, and I have 400mm clear to the rear of the evaporator.

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rhh2348

(@rhh2348)

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Topic starter 19/02/2024 1:07 pm

Posted by: @harriup

↑

28mm pipework should run as far as you can take it into the house - you need volume of water in the system to cover defrosts.

Yes. Where would the optimal position and method of stepping down? I assume nearest the unit, so at the unit's inlet/outlet - but not sure how.

You protect the outside pipework and the pump either by having glycol so the water can just sit at very cold temperatures, or you circulate the warm water in the pipes to keep the outside parts from freezing – the anti-freeze valves are a fail-safe should you be unable to power the water circulation. You would not want to be dumping glycol.

Thank you.

Full bore valves are isolating valves...

From the BES component diagram in the OP (relevant section below), it shows 'isolator valves' and 'full bore valves' - though, having just looked at it again, I've just noticed the isolator valves are inside the property:

The isolator valves I mentioned describing my install are Inta lever ball valves - I assume these should be full bore to maximise flow rate and be positioned as the primary pipework exits the brickwork outside? Is there any value in having a second set at the unit's inlet/outlet too?

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rhh2348

(@rhh2348)

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Topic starter 20/02/2024 11:58 am

Posted by: @rhh2348

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What's the optimal / minimum length and shape of flexihoses (and why, if not for best performance and least vibration)?

I'd appreciate anyone's thoughts on this, having read in one or two posts (I now can't find...) that longer hoses can reduce/eliminate vibrations travelling through the primary pipework elsewhere.

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