The drain pipe system under the sink. Not the actual one, but very similar.
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Some of you may recall a similar Air Conditioning Incident all the way back in September 2021 (almost 5 years ago now, if you can believe that), especially if you’re a veteran TechStation reader. After all this time, the same kind of incident has just cropped up again, in the height of summer. Incident details are shown below.
It was the afternoon of Thursday, August 13, 2026, the day when Air Conditioning Incident II took place. A serious clog had been observed in the bathroom sink, which had emerged nearly out of nowhere and stopped up the entire draining process such that no water could get through. This was the second clog in under two months, which was extremely unusual and a serious red flag. (Getting deja vu yet?)
This came during a time when the H was very bad and in dire need of attention–an unfortunate thing because this would most likely delay the completing of the H even further. But enough of that (and as of October 9, 2026, there was no delay whatsoever). During the bathroom sink unclogging process, a steady drip was observed coming out of the secondary air conditioner condensate drain pipe in the gutter, outside the guest room window. This is exactly what had happened after a Bike Session™ in September 2021. The dripping was in fact quite constant and perhaps even more aggressive than that of the previous incident, oscillating with the intensity of the air conditioning system.
For context, no periodic HVAC service had been performed on this system on a regular basis since the last cleaning, in 2021. The dripping had not been observed prior to the unclogging of the bathroom sink; earlier that day there was no dripping whatsoever. This is an interesting observation and might lead you to believe that the clogging process resulted in the condensate drain line going off the wall, getting clogged, and initiating an emergency procedure.
The immediate next step was to contact an HVAC contractor to first fix the dripping condensate line issue. This mirrors the first action that was taken in 2021. After that, the intent was to contact a plumber to resolve any new issues with the drain that may have resulted from the flush causing trouble, and investigate some miscellaneous leaking faucets.
Results from the HVAC contractor call
This call took place in August 2026 serviced by The Cold Truth. A follow-up periodic maintenance appointment was scheduled for the winter (November-December). Hopefully they will do it properly™.
During the call, the clogged secondary air conditioner drain line was unclogged and blown out through the bathroom sink. The broken/intermittently-malfunctioning diverter motor was also disabled entirely during the call, following the diagnosis of the failing motor. As a result, the entire house would be supplied with air when the upstairs thermostat requests the system to turn on, instead of just the upstairs zone.
This initial call from August also involved the blowing of the primary air conditioner drain line, which would go on to cause another bathroom sink drain clog due to contaminants moving gradually through the system from the blowout. Following are the details on this subsequent incident.
The second clog, October 2026
On October 8, 2026, the same bathroom sink stopped up completely again, with almost no warning whatsoever. While the outside air conditioner secondary drain was not dripping at the window, the sink was exhibiting all of the same symptoms as it had during the previous few times, pointing to an issue with air conditoning condensate contaminants.
A plumber was called and arrived the following day; the sink drain was fully cleared out and flushed, and it was confirmed that the same algae contaminants were clogging the system. Hot water was run through the system and no further clogs were observed. A possible explanation for this is that the air conditioning service from August 2026 resulted in a gradual flood of bacteria back into the sink drain–or the service contractors simply did not clear the system effectively. We will see if the sink clogs again in November or December; a report will be published here on this blog if so, or an edit will be made to this post. The total cost for the sink unclog operation was $318.
As a side note, an outdoor water spigot was also replaced during this October plumbing call. The cost for replacing the spigot was $422. No other issues were observed.
