Help From Owners (or installers) of Mitsubishi PEAD Ducted Heat Pumps

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Paul1977

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#272244 16-Jun-2020 11:24

Following up from my more general thread about condensate drainage, I now have some very specific questions:

We are having a PEAD-M125JAA installed. The outdoor unit is a PUZ-ZM125VKA-A.TH and is to be located in a concreted utility area (the concrete has not yet been poured).

I can't find any diagrams or dimensions showing drainage hole(s) for the outdoor unit, and haven't yet had a lot of joy getting the info from the installer - except that they have multiple drainage points.

I have found specs for the UK model PUZ-ZM125VKA.UK

If I'm reading this correctly (and assuming the NZ model is the same) it looks like there are 5 drain holes.

1. Am I correct that these units have 5 drain holes?

2. If so, is there a way to do some sort of soak pit to capture the drainage from all 5 drain holes?

3. Does anyone have access to the specs/service manual of the NZ model so I can confirm the dimensions and placement of holes are the same as the above diagram

4. How are others who have these units draining the condensate?

Any help or advise would be greatly appreciated (especially from owners or installers of Mitsubishi PEAD ducted systems)

Thanks

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Froglotion

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#2505931 16-Jun-2020 16:32

I don't have that unit.

But what i'd suggest doing is just digging a hole under where the heatpump is going, fill it with stones and put a 40mm waste pipe into it. Have the 40mm waste come up under the heatpump against the wall. They can run a flexible conduit from the unit to that drain. The unit will sit on feet that will allow enough fall from anywhere on the bottom of the unit, to get to the drain. 2c

Paul1977

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#2506685 17-Jun-2020 14:38

Froglotion:

I don't have that unit.

But what i'd suggest doing is just digging a hole under where the heatpump is going, fill it with stones and put a 40mm waste pipe into it. Have the 40mm waste come up under the heatpump against the wall. They can run a flexible conduit from the unit to that drain. The unit will sit on feet that will allow enough fall from anywhere on the bottom of the unit, to get to the drain. 2c

This is a similar approach to one of the suggestions the installer had.

But he thought create a rebate in the concrete slightly larger than the unit, with a soak pit in it. The heat pump sits in the rebate so no matter where the condensate comes from it can't get past the edge of the rebate. The concrete would be sloped to direct the water into the soak pit. Fill the soak pit and the entire rebate with stones level to the finished (higher) surrounding concrete.

His other suggestion was put it in steel brackets attached to the side of the foundation with an unconcreted area beneath it filled with stones.

Have started a new thread specifically about advantages/disadvantages of outdoor heat pump units on brackets vs a concrete pad.

Kickinbac

468 posts

Ultimate Geek
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#2508355 19-Jun-2020 20:01

Yes, five drainage holes in base.
I can get access to service and technical manuals at work.
Usually the outdoor unit comes with rubber plugs and a hose connection to gather the condesate and pipe it away. If not you can usually buy a kit with these.

Kickinbac

468 posts

Ultimate Geek
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#2508613 20-Jun-2020 10:52

That outdoor unit is 113kg. I would be cautious about hanging on a wall brackets unless its the only way.

elpenguino

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#2508693 20-Jun-2020 13:04

A good thing about being on the wall is that leaves and rubbish won't collect around the bottom of it.

Your wall will need to be strong for 113kg though.

For tidiness I like the idea of the sloping concrete underneath leading to a soak pit but i suggest you think of the future. What happens in 5 years when this outdoor unit fails and another of different shape and size is fitted?

Don't paint yourself into a corner of customisation.

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Kickinbac

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#2508695 20-Jun-2020 13:19

elpenguino:
A good thing about being on the wall is that leaves and rubbish won't collect around the bottom of it.

Your wall will need to be strong for 113kg though.

For tidiness I like the idea of the sloping concrete underneath leading to a soak pit but i suggest you think of the future. What happens in 5 years when this outdoor unit fails and another of different shape and size is fitted?

Don't paint yourself into a corner of customisation.

Personally I wouldn’t hang such a large unit off a timber or steel framed wall. The risk of noise transfer into the house becomes greater as larger units have one or two fans and a larger compressor. Most outdoor units are set on plastic feet on slab or pavers to allow air flow and clearance to clean out. It should have at least a 100mm gap to the wall for cleaning and airflow clearance. The OP seems mainly concerned with condensate under the outdoor, possibly due to it being next to a path.
Also a heat pump unit will last (hopefully) at least 10 years, more like 12 to 15 years.

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Paul1977

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#2508933 20-Jun-2020 20:25

Thanks for the responses. My gut tells be a concrete pad is the way to go as far as mounting. For condensate drainage the installer and concrete contractor both have different ideas.

Installer suggests a rebate and soak pit as described in previous post.

Concrete guy is suggesting strip drains around the unit, but I’m not sure about the looks of that idea. I’ve seen it done at a show home and thought it looked a bit odd.

Kickinbac

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#2508958 20-Jun-2020 21:30

Paul1977: Thanks for the responses. My gut tells be a concrete pad is the way to go as far as mounting. For condensate drainage the installer and concrete contractor both have different ideas.

Installer suggests a rebate and soak pit as described in previous post.

Concrete guy is suggesting strip drains around the unit, but I’m not sure about the looks of that idea. I’ve seen it done at a show home and thought it looked a bit odd.

Is the soil free draining? Why not build a mini soak hole? Get a length of 150 PVC pipe, drill holes around it dig it down vertically as deep as possible (at least a metre) and fill with scoria. Get the bung/hose kit for the unit and put a hose in the top. Ideally put it directlly under the outdoor unit to hide it.

I did this on a project with this actual problem as client was complaining about the always wet path. We pumped outdoor unit down, moved the outdoor unit, core drilled through the path, used a post hole borer to dig down as deep as we could and filled with gravel. Sorted the problem.