noise at condesnsate

Heard something weird at an inspection today that is a first for me. When walking on the exterior near the primary discharge I heard some air movement at the pipe. It wasn’t coming out of the pipe but sounded like it was coming from just inside the wall somewhere. It wasn’t your typical blowing sound either, it was more like a burp or gargle without water. Hard to explain. Then when I walked on the other side I heard the exact same noise at the nieghbor’s. Anyone run into this or have an idea what this is?

Could have been sucking air due to improper condensate trap setup.

Some systems are critical and will suck air which blows condensate all over the coil causing rusting and other performance issues.

Any water coming out of it at all? Look like the proper amount?

Had a Trane gas pack once that was like that. Had to prime the trap every spring.

None at all, but it was a bank owned and had been vacant with the temp set at 88ish. Gave it 2 hours with no dripping.


Had similar concern with todays H/I. Vacant house, A/C off at T’stat.
I turn system on at 11:30am upon arrival, set T’stat at 76, and by 11:50 was pouring water.
The T’stat was reading 88 inside, and when I left at 2:00pm, it was still reading 88 on the T’stat. The system was blowing 59 degree air, apparently doing all it can do, and still not budging the indoor temp.
Bottom line… the unit should be dumpimg water fairly quickly if mechanically operating. Noise may be coming from trap design, possible stopage. I’d look at the furnace/evap.coil location for leakage around or through the furnace. I’d probably defer to and HVAC Contr. for diagnostic duties.

Or could have been blowing air through the water filled AC condensate pan drain trap positioned in the supply plenum above furnace.

I wrote if off for evaluation. I also asked for the results. If I get them, I will follow up.

It sounds like a situation I had not long ago. The condensate line was clogged and as a result was being drawn back into the unit (there was an open cleanout directly above the trap, that’s where the noise was coming from)