New evaporator coil plumbing

[Mandrake]

The drain for an evaporator coil should have a trap and then slope to septic / sewer.

The secondary drain is on the catch pan and can slope to an eave or anywhere you don't mind getting water someday. (If I understand this correctly).

Is there an issue with running both to the same drain stack? Is that asking for trouble on the day they clog is somewhere past the stack?

[Robert Adams]

Yes there is an issue. The secondary drain needs to be run somewhere you will see it dripping. Usually over a kitchen window etc. So if you see water dripping you know your drain is plugged and needs to be fixed. If you don't notice it the pan drain will eventually plug and overflow water and damage your ceiling.

[daddo]

Adams is right.

Also, if your draining into a septic/sewer, you should have a larger trap. A 1.5" or 2" PVC trap will lessen the chance of the trap going dry in the winter.

[Mandrake]

Thanks,

I'm debating the location of a new installation in my workshop. The choices are either a closet installation located above the slab (door access from the main floor with the bottom few feet being the air return) versus an attic installation.

With the closet, I have the drain connection in the slab. However the unit would be too low to gravity drain the pan to anywhere except the same drain.

With the attic installation, I can hit the same main drain, and run a line for the pan 10' horizontal and out an eave. The eave location would be by the back door, so it would get noticed whenever someone went to the back yard.

If I eliminate the closet idea, that adds a few more usable square feet to the finishing room, but maintenance on the unit would require a trip to the attic. But that is also how all of the homes in our area are built.

[daddo]

I have never liked them in the attic. Reasons being that the drain, no matter how careful you are can end up leaking on a ceiling and causing damage or the ceiling to collapse. The unit sitting in 130+ temps is not the best conditions and if there isn't ample room to service the unit, it won't get serviced as well. There is always the chance of sweating during certain times of the year.
But that is your decision to make.

If it is installed in the attic, you'll have a main drain shut off switch and aux pan and shut off switch- each separate runs.

In the closet, you will have a main drain shut off switch, an aux pan as well and an aux pan shut off switch and drain.
What I would do is install the aux pan under the unit in the closet on the main floor with it's drain running to the main drain but with a shut off ***** at the pan so the pan will fill up if there is an overflow- the aux pan switch will shut down the a/c. This way you know there is a problem with the main drain. Once the main drain is corrected, then you can open the shut off ***** and drain the aux pan via the main drain connection- then close the ***** back up for the next time.
There is a secondary tap on the indoor coil for the aux drain. That will be piped directly to the aux pan underneath. The aux pan should cover the intire floor underneath and can be tilted toward the aux pans drain connection where the shut off switch is also.

Works for me.

[Mandrake]

Sounds good. I think I will stick with the original plan to do the closet install. The switches and pipe configuration make sense.

Thanks

[Robert Adams]

The only things I like about the unit being in the attic are the non wasted space in a closet. Much easier to put returns in the ceiling which is good in the heat belt. And attic units are way way quieter. Got a 5yo Lennox upflow in our house and it's as noisy as a jet engine. However the Rheem I put in my parents house is whisper quiet in comparison... Ours gets replaced soon.

[daddo]

Robert Adams said:

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The only things I like about the unit being in the attic are the non wasted space in a closet. Much easier to put returns in the ceiling which is good in the heat belt. And attic units are way way quieter. Got a 5yo Lennox upflow in our house and it's as noisy as a jet engine. However the Rheem I put in my parents house is whisper quiet in comparison... Ours gets replaced soon.

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My BIL, just south of Weatherford has a second floor system in the attic. You can't hear yourself think when it's running. The air handler was installed right at the ceiling return grill.
When we visit overnight, I have to run the blower in the "on" position because it will jolt me awake every time it starts up.

Poorly done install.

[Robert Adams]

daddo said:

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[blockquote]Robert Adams said:

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The only things I like about the unit being in the attic are the non wasted space in a closet. Much easier to put returns in the ceiling which is good in the heat belt. And attic units are way way quieter. Got a 5yo Lennox upflow in our house and it's as noisy as a jet engine. However the Rheem I put in my parents house is whisper quiet in comparison... Ours gets replaced soon.

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My BIL, just south of Weatherford has a second floor system in the attic. You can't hear yourself think when it's running. The air handler was installed right at the ceiling return grill.
When we visit overnight, I have to run the blower in the "on" position because it will jolt me awake every time it starts up.

Poorly done install.

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[/blockquote]

Ugh see that allot here. Our unit is just loud and echoes through half the house. The closet it is in is going away so the new one is going in a larger closet and getting super insulated.

Weatherford is a short drive from here too.

[Mandrake]

Insulating the closet for sound is a good idea. I'll be insulating a dust collector closet nearby as well.

But with a closet unit, I imagine an updraft with an intake plenum framed up just below it. Like your examples, I suspect most of the sound transmission will be through the filter grate.

I'm thinking it would be smart to find someone who can run a heat load calc on the building, size the capacity, and help pick an actual air handler / evap coil unit. That will give me a physical size to ensure what I'm framing has enough room and that I can add proper room for insulation if needed.