Incorrect installation of the air conditioner condensate drain pipe will lead to water leakage problems, especially when the drain pipe is hidden. not only do we need enough slope, isolations and other aspects are also important.
A/C condensate drain pipe can be installed in two ways; a) exposed, and b) hidden. most drain pipes are not hidden. they hang above the ceiling or run along the exposed wall.
Reading: How to connect ac drain pipe
for hidden drain pipes, they can be installed inside the concrete floor and inside the brick wall. concealed drain pipes offer a better interior that is normally practiced in luxury places such as mansions, condominiums, hotels and high-end offices.
Exposed drain pipes are more common in residential homes because they are cheaper, easier to install, and have less risk of failure.
The most common type of air conditioner is the wall-mounted type. the condensate drain pipe for wall mounted type air conditioner is very simple. but make sure the drain pipe is always lower than the air conditioning unit.
The condensate trap and drain pipe riser are not required for the wall mounted model. For all drain pipes, make sure to have at least 1/100 or 1% slope for even water flow.
For such a gradient, the slope of the drainage pipe can be easily noticed with the naked eye.
however, the industry used 1/4″ per foot as the standard for any pipe size less than 3 inches that uses gravity flow. such a standard is equivalent to a gradient of 1/48 or nearly 2%.
As for drain pipe insulation, 3/8″ thick closed cell insulation is usually sufficient to prevent condensation. if your drain pipe is exposed to high temperatures (over 30°c), you should use 1/2″ thickness instead.
For concealed drain pipes, the concrete wall and floor act as insulation, and therefore there is no need to have insulation for drain pipes that are hidden within the wall or floor.
Insulation must cover the entire drain pipe (except hidden sections), including joints and connection to the air conditioning unit. any pipe surface left outside could cause condensation.
supports and accessories
Drain pipe should be supported with galvanized steel hanger at approximately 3-4 foot intervals to prevent sag, which will allow sediment to form at a faster rate and eventually clog the drain line. p>
It is usually best to place the support near the elbow of the pipe.
If you hide the drain pipe and discharge into a floor trap, be sure to use a suitable adapter at the outlet to join the drain pipe and plumbing downspout properly to prevent condensed water from entering the floor. concrete.
Also, you should protrude the drain pipe about 1 inch into the plumbing pipe to prevent condensed water from dripping back onto the concrete floor.
When I started working, I didn’t know anything about the drain pipe adapter. we just make a hole in the plumbing pipe, insert the drain pipe into it, and call it a day. consequently, we end up with many defects where condensed water returns to the concrete floor. it took us a few weeks to fix them all. so make sure you don’t repeat my mistakes.
however, you can wear a simple slimming t-shirt and it will work too.
Installation of condensate drain pipe for ducted air conditioners is different from wall-mounted type. the drain pipe of ducted air conditioners should have a condensation trap to prevent the air conditioners from being exposed to the open ended drain pipe which creates a suction preventing condensed water from being discharged.
Ducted air conditioners typically have strong suction due to their high airflow. without a condensation trap, the condensation water will not flow into the drain pipe but will overflow into the air conditioner.
Some people place a secondary drain pan under their ducted air conditioners to reduce the risk of leaking condensation water destroying the ceiling. if you want to do the same, you can use a drain pipe for both the secondary drain pan and the air conditioner.
When it comes to the drain pipe for ceiling cassette type air conditioners, you should raise the drain pipe according to the manufacturer’s instructions stated in the user’s manual to reduce the noise of the drain pump inside the unit cassette.
however, you can back off half the length of the standpipe after elevation so your roof can be higher or the drain pipe can travel further while maintaining a good slope.
all drain pipes can be joined as long as they are the right size.
good installation practices
As a general rule, we should avoid having too many bends when installing the drain pipe. each curve is resistant, which will increase the chances of water stagnation, which will accelerate the formation of sludge that will eventually clog the drainage pipe.
for exposed drains, class d pvc pipes are usually used. As for hidden drain pipes, you should use class e pvc pipes that have a thicker wall to withstand the harshest conditions, especially during the pouring of the concrete floor.
If the drain pipe penetrates through the walls, be sure to install a pipe sleeve that is 1 or 2 sizes larger than the drain pipe to prevent the drain pipe from cracking due to movement or compression off the wall after a while. yes, brick walls and concrete walls can move on a small scale due to thermal expansion/contraction and others.
flow test and leak test
Most of the time, a basic flow test is enough to check if the drain pipe is installed correctly and can drain water properly. you only need to pour water into the inlet to see if the water flow is good. pour slowly to mimic the flow rate of condensed water.
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However, for the concealed drain pipe, I would recommend doing a leak test by sealing the outlet and filling the drain pipe with water for 24 hours to check for any leaks.
Concealed drain pipes are difficult to detect water leaks. however, you can use a moisture detector to find the leak inside the wall or floor. note that you don’t need an expensive one since the drain pipe is not deeply embedded in the wall or floor.
A/C condensate drain pipes should have a slope of at least 1/100 or 1%. Most of the time, 3/8″ thick closed cell insulation is sufficient, but you can go with 1/2″ thick if the drain pipe is exposed to temperatures above 30°C.
Drain pipe should be supported with galvanized steel supports at approximately 3-4 foot intervals, and it is usually best to support the elbow of the pipe.
If you are hiding the drain pipe, be sure to use a proper socket adapter and protrude the drain pipe about 1 inch into the plumbing pipe to prevent condensed water from dripping back onto the concrete floor.
always install a condensate trap for ducted air conditioners and raise the drain pipe according to the manufacturer’s instructions if you are installing ceiling cassette air conditioners.
all drain pipes can be joined as long as they are the right size, but avoid having too many bends.
exposed drain pipes should use class d pvc pipe and concealed drain pipes should use thicker class e pvc pipe.
Perform a basic flow test after installation to ensure water can flow smoothly. Also, you can do a leak test by sealing the outlet and filling the drain pipe with water for 24 hours to check for any leaks, especially if the drain pipe is hidden.
Check out my post on Air Conditioner Water Leaks: Symptoms, Causes, Solutions and Problems. prevention to understand all water leak problems so you are aware of them and take steps to prevent them from happening.
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