I'm puzzling over an issue I'm having. For some reason, the condensate from my AC coil seems to prefer going out the secondary drain. The primary works fine for a few days, then I'll find it spilling out the secondary drain on the floor. The primary is not clogged. I ran bleach water down it last time this happened, and put 2 gallons down with no issues.
Here's what confuses me...it only does this if the vent before the P trap is capped. If I remove it (as pictured) everything works well. But if I put a cap back on that vent, it's going out the secondary drain in a couple days.
This is an upflow furnace. The coil is under positive pressure. I suspect static pressure is higher than optimal, just based on how the installer zoned the system. We have one big zone, one small zone, and the fan is not a variable speed one. There is a bypass damper, but it's wide open when the small zone runs.
And for background - I installed the primary drain you see last fall. It was previously vinyl tubing coming out the primary. The secondary was capped. I moved the vinyl tubing over from the primary to secondary, then built the PVC drain you see in the picture for the primary. The issue I was trying to solve was that the tubing kept getting algae growing in it and plugging. Then I had condensate all over, since the secondary was plugged.
Here's my only guess as to what's happening - it's probably wrong but it's all I could come up with. The secondary drain is not trapped, so it does pass air. With the cap on the primary drain before the vent - it's not passing air. Could it be possible the air blowing out the secondary is taking the condensate with it? It's all I could come up with.
I could leave the cap off the drain forever, and that seems like it would solve the issue. But it seems like there is a deeper underlying issue, and I'm trying to figure out what that is. I'd appreciate any thoughts!
Here's what confuses me...it only does this if the vent before the P trap is capped. If I remove it (as pictured) everything works well. But if I put a cap back on that vent, it's going out the secondary drain in a couple days.
This is an upflow furnace. The coil is under positive pressure. I suspect static pressure is higher than optimal, just based on how the installer zoned the system. We have one big zone, one small zone, and the fan is not a variable speed one. There is a bypass damper, but it's wide open when the small zone runs.
And for background - I installed the primary drain you see last fall. It was previously vinyl tubing coming out the primary. The secondary was capped. I moved the vinyl tubing over from the primary to secondary, then built the PVC drain you see in the picture for the primary. The issue I was trying to solve was that the tubing kept getting algae growing in it and plugging. Then I had condensate all over, since the secondary was plugged.
Here's my only guess as to what's happening - it's probably wrong but it's all I could come up with. The secondary drain is not trapped, so it does pass air. With the cap on the primary drain before the vent - it's not passing air. Could it be possible the air blowing out the secondary is taking the condensate with it? It's all I could come up with.
I could leave the cap off the drain forever, and that seems like it would solve the issue. But it seems like there is a deeper underlying issue, and I'm trying to figure out what that is. I'd appreciate any thoughts!
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