Quote:
Originally Posted by Fuzz
Ya, that brings fresh air into the furnace(not for combustion), mine has a damper that closes it so it only opens when the furnace is running. I've never had a condensation issue, I assume it would only happen when really cold.
|
Ya that's makeup air.
Same line-in from the outside as combustion air, except makeup terminates in the cold air return rather than just in the furnace room for combustion air. Newer houses the makeup air generally is motorized (both a motorized damper and power sucked in by code) and/or run through an HRV to warm it up before it gets sent to furnace.
But most older houses just have a line right into the cold return and sometimes a manual damper. OP its nothing to be alarmed about. I'd be slightly concerned (strong word) if the condensation was IN the cold air return (possibility of getting some mold/mildew), but you can check that directly through the little black plug you can pull out and feel around. And if it were pooling inside the cold duct too, you can just drill a small hole for it to drain through and leave it unplugged without issue.
If it only happens when it below -20 I wouldnt stress much anyways, lots of weird #### happens at that temp