Understanding Condensate Drain Lines

The primary condensate drain lines normally drains into the household sewer system through an open connection to an active p-trap. In some cases, these active p-traps are the bath tub or bathroom sink p-trap; should this be your case, be sure to read the special instructions in maintenance, below. Should the evaporator coil’s primary drain line become clogged or should the primary drain develop a leak, condensate should overflow or leak into the emergency drain pan thence into the emergency drain line. The emergency condensate drain line, drain line, drains to a conspicuous place outside the home. Water dripping from the emergency drain line is a warning indicator that something is drastically wrong with primary condensate drain system. You should not delay in calling a service technician.

Problems- With primary condensate drain lines stem form plant pollen, fungus spores and other particulate matter entrained in the air stream passing over the wet evaporator coil. They are captured by the condensate draining off the coil and are carried into the drain system. There they produce algae, mildew, and fungus growths which can clog the primary drain system. While the emergency drain lines are normally dry and clear, they are open to the atmosphere. Wasps, called “mud-daubers”, are known to nest in these open drain lines, there by rendering them useless; always at the wrong time.

The larger diameter pipe of the household sewer system yields two results. First, it usually precludes problems with condensate. Second, the maintenance and repair beyond the open connection to the p-trap is outside the scope of the air conditioning technician. Some older systems drain into an inactive p-trap; this can lead to the long term build up of sediment, dried algae, etc… in the trap and result in an overflow of the plumbing drain system. If the active p-trap also services a bath tub or bathroom sink, clogs can be caused by hair, soap scum or other material draining from the tub or sink. Clogs in the household sewer system require the services of a licensed plumber.

Maintenance- Test both the primary and emergency drains with water. If a restriction is detected, he or she clears the obstruction with compressed air. Blowing out a drain line will usually open a clogged drain line, but it cannot remove growing algae or other deposits from the pipe wall. Our technician will place algicide tablets in the primary drain pan. While algicide is used prevent algae buildup, algicide kills any existing algae. The dead algae may slough off the pipe wall and pass into the sewer system or drift down stream to a restriction and accumulate there resulting in a clogged drain.

Special Instructions- Bathtub or bathroom sink p-traps. If the active p-trap in your system is the trap for a bath tub or bathroom sink, there is the possibility that material flushed from the condensate drain system may combine with bathroom debris already in the trap, to begin formation of a clog. Should one of these plumbing drains clog, condensate will fill the sink or tub and overflow without any warning such as water dripping form the emergency drain line. After any work on your condensate drain system, the drainage of the sink and tub should be observed. If either drains slowly or backs up, plumbing maintenance is needed.

Other measures our technician my recommend are the installation of a float switch in the emergency condensate drain pan and an Easy Klear clean out valve. Should both the primary and emergency drain systems fail, the float switch functions to turn off the air conditioning system, stopping the production of condensate until the clog is cleared and the drain pan emptied. The Easy Klear helps improve drain line maintenance.

Despite all of these precautions, there can be no guarantee that your condensate drain system will remain clear. Your condensate drain system can become clogged at anytime and should be watched closely after it has been serviced, especially when algicide has been applied. Older systems with accumulations of algae can become clogged anytime algae breaks loose from the pipe wall and drifts downstream to a restricted point. At a restriction, algae will accumulate and grow unit it blocks the drain pipe. These restrictions can grow into a fully clogged drain line in less than one month.

Should a problem occur or our technician detect a problem with the p-trap or plumbing drain line (household sewer system), he or she will recommend the services of a licensed plumber. In our opinion, blowing out a large diameter plumbing drain line is not and effective repair. The household sewer system, beginning at the open connection to the condensate system, is the domain of the licensed plumber.

Liabilities- Whenever the air handling unit of an air conditioning system is located in an attic or the upper stories of a building, the risk of water damage due to drain stoppage and condensate overflow is inherent and unavoidable. Proper design and installation coupled with timely and consistent maintenance can minimize the probability of an overflow, but cannot absolutely prevent it. Therefore, our warranties specifically exclude liability for water damage due to condensate overflow, and special, consequential or incidental damage caused by stoppage of a condensate drain system.

Your homeowner’s insurance should include coverage for water damage resulting from condensate overflow or other water leaks. We suggest you confirm your coverage.