Clogged Furnace Condensation Drain Hose

[Activities Editor]

This week I noticed water overflowing from the condensation pump near the furnace. The 3/8” drain hose that leaves from the pump to the upstairs laundry room drain was clogged from algae and debris. Apparently it has happened to others in HWs as well. To fix this issue, you need to clear the obstruction by adding air pressure through the hose. Either by blowing or using an air compressor.

To help reduce the chance of it occurring, you can add tablets to the pump every week or two to prevent the algae from growing in the line. The link to the ones I bought is: Rectorseal 68115 Hydrex A/C Tabs-200 Tablet Bottle https://www.amazon.com/dp/B008A3UCYS/ref=cm_sw_r_cp_tai_4XenAbB4G5RY8

[John Goglia]

FYI, according to Jason LaMarche who installed many of our furnace humidifiers you can also add 1 cup of vinegar to a gallon of water and pour that into the pump once or twice a year to keep the system from clogging. Myself and others have done this w/o any problems – John Goglia

[Mary Lou Gould]

Hi Folks

We experienced a similar problem about a year ago. I could not clear the line with air pressure and was unable to snake it clear. I purchased materials and replace the entire run.

I altered the new run a couple of ways to avoid future issues. The most significant issue–and I think the root cause–was the way they ran the hose into the laundry-room trap. In our instance, the drain hose was inserted too far into the laundry drain pipe. The hose was resting INSIDE the trap. What we witnessed was a backflow sufficient to actually EMPTY the trap. The backflow could be seen traveling back down the hose, into the basement, and back into the condensate pump well…along with any grime that collected within the trap. This behavior over time resulted in significant build up of residue on the walls of the drain hose…and eventually clogging it along a significant portion of the hose run.

My solution was to install a backflow preventer, AND ensure that the hose in the laundry room DOES NOT rest in the pool of fluid within the trap.

We’ve observed no further discoloration of the hose, nor flow problems since.

…also the noises from the laundry room when the condensate pump is in operation are no longer noticeable.

best regards,

Fred (29 black forest circle)

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