The Truth About Drain Lines

drain line ductless hvac mitsubishi

GEN3 is working on becoming Philly’s leading installer and servicer of mini splits. (What’s a mini split? Click here!) A frequent source of confusion from customers or potential customers looking to cool their homes efficiently is the drain line. We do our best to let folks know what the finished product will look like and to explain the process from start to finish.

What is it? Part of any air conditioning system is cooling. Part of cooling is removing moisture from the air. A drain line allows the moisture that is removed from the air (sucked in at the top and spit out at the bottom after crossing a cooling coil) to exit the unit. It turns into water quickly, especially on the humid days! Installing a drain line allows the excess water to be directed somewhere versus just leaking all over whatever is under the unit. Have you ever stood under a window unit on hot day? Chances are you will have felt a drip if so. The drain line can do its job in a few different ways.

Gravity! Sir Isaac Newton and his apple tree are a huge help when it comes to drain lines. The easiest way to get the water away from your unit (and often your bedroom/living room/prized possessions, etc.) is with a little bit of help from our friend gravity. Mini split indoor units come standard with a drain pan and a small hose. The drain pan catches the water and the hose allows it to exit the unit. The hose that comes with the unit is about a foot or so long (depending on the brand). Often during installation an extended drain line to this hose. This can be done so that the drain line can reach outside (if your unit is on not on exterior wall or if your walls are thick for example), to the ground (some folks prefer to not have something dripping on passersby from above or don’t want something sticking straight out of their wall), or to a pre-existing structure (such as a laundry tub or slop sink in a basement).

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Pitch perfect. The actual drain line itself can either be a flexible hose or hard piped PVC. Differing installations call for different applications and we have established some drain lines with a combination of these two methods. In any case, the drain line must maintain pitch so that the water does not sit in the line instead of draining and gravity does its job properly. In cases where water sits, it will begin to backup all the way to the unit and overflow the drain pan. To maintain pitch, GEN3 installers follow one simple rule: there must be a ¼ inch angle downhill per foot. This can be checked easily with a level!

Pump up? What about situations where aesthetically a pitched drain line is not an option? Or it’s not plausible physically to have a gravity run line installed in a home (space limitations, or all party walls, etc.)? Condensate pumps can work miracles in these situations. A condensate pump uses tubing (flexible line of PVC) attached to the drain hose of the indoor unit to bring the water to the pump’s reservoir. When the water reaches a certain level it is then pumped out of the reservoir to a drainage area electrically through another tube. Pumps come in various shapes and sizes. Some can be tied into the unit’s electrical and some require an outlet (this can be easily installed by one of GEN3’s electricians).

Something to consider about pumps is aesthetics (depending on the make and model they are often visible.) An example of how a pump with a reservoir below an indoor unit can be found in GEN3’s office. The white piece underneath the mini split head houses the pump and its tubing. In the office’s case the pump sends the liquid to our central drain line in the ceiling across several workspaces and then eventually outside. Another consideration is that these pumps are not silent — you can hear when they turn on and pump the water out. For that reason, some folks prefer not to have a pump in a bedroom unit or anywhere it might be disturbing.

Now you know the truth about drain lines! An informed consumer makes a happy customer. Schedule a free mini split estimate today by calling our office. One of GEN3’s qualified technicians will visit your home or office and work to meet your drain line needs.