Minisplit code requirements
Minisplits installs are rarely inspected and there seem to be many variations on how people do things. im trying to find some definitive answers to some code related questions.
1. Condensate drain lines: assuming 3/4″ pvc. Im aware it can drain outside on the ground or into a floor drain. can it be drained into a washing machine standpipe? How about the stand pipe garbage disposals drain into? I.e. with an air gap.
2. Would this drain line require a ptrap in the case of a ducted air handler? I dont see the point of a trap unless its tied into the sewer pipe directly?
3. Can 2 drain lines be combined before the drain location? I.e. 2x 3/4″ pvc into a Y then to one of the drain locations mentioned above? (This could be useful when draining multiple air handlers into a washing machine standpipe box which isnt that big to accomodate multiple drain lines and the washing machine drain itself.) Can the 2″ stand pipe accept the washing machine drain pipe as well as a 3/4″ condensate drain anyway?
4. Should any cleanouts be installed? If so where?
5. Are secondary drain pans with its own drain line required to be installed under a ducted air handler? Like a water heater drain pan?
6. Electrical: is it required to have 3′ of clearance between outdoor condensers? I read some argue that NEC requires the 3′ because there’s live electrical connections there. Yet, most manufacturers says minimum clearance between units being around 12″. Obviously many people have installed multiple outdoor units with less then 3′ between them out of necessity – myself included.
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Are you looking for references in the I codes? I can give you some references to municipal codes, but I expect you'll be disappointed
2. P trap in your condensate line will eliminate air flow through your condensate line. There are p traps designed specifically for condensate lines that allow easy cleanout options
3.Yes multiple drain lines can be linked. look at manufacture installation instructions for specifications for different units. this is common in flush ceiling split units
4.see 2.
5. yes generally (or always?) drain pans are required and the ducted unit must have an auto shut off if it detects water in the drain pan.
6. Use manufacturer clearances as they are all UL listed and code says you install to code or manufacturer specification
Thanks for the info!
Why is airflow bad in the condensate line if no swewer gases are involved? (Draining to a floor drain with an air gap).
Is this ptrap required by code?
A drain pan requiring its own drain line as well as an auto shut off is a component i didn't know i have to install. The drain pan i can source - get my roofer to bend up a pan for me. Adding yet another drain line to the floor drain is doable but a real pain as its starting lower than the condensate drain, so i might have to furr the ceiling below down for tis additional drain line. The auto shut off system i really have no idea where to even begin. Is this some additional module i order and plugs into the airhandler? Do you have a link to point me in the right direction? This is for a 12kbtuh slim/consealed ducted unit.
It’s either an auto shut off or a drain. And the drain has to go to conspicuous place so you know if it’s running, like over a window is common. But the auto shut off is often a part from manufacturer of air handler. I’m sure there are also relay ones but have never used one.
The air through condensate will enter your house, so depending on how tight you want your house, this is an air leak that will effect ACH. No I don’t believe it’s required by code
If you don’t install p trap you should at least install a clean out.
Understood. I found the code section relating to secondary drain pan or water sensor etc. problem is that my unit has the electrical box access screw as well as the filter access from below, so a drain pan would simply get in the way. I wonder if this particular unit isn't designed to have s secondary drain pan under it......
I doubt it is not required as its required for all evaporator coils that can damage the building structure if they leak. Usually you will hang the handler and then have the pan either hanging lower or on floor below. Just do a google image search of "indoor air handler drain pan" to get some ideas.
My minisplits intensely dislike p traps. They can be problematic to drain even with an 15 foot drop. I put a piece of coarse foam[ridge vent] in the end of the drain to keep the bugs out.
I have heard it said here that the p traps can dry out during the heating season when there isn’t any condensate being produced.
https://www.greenbuildingadvisor.com/question/how-best-to-manage-minisplit-condensate-drainage
https://www.greenbuildingadvisor.com/question/condensate-drain-line-installation-for-minisplit-head-units-when-you-cannot-run-outside