I visited a house a couple of days ago that was full of HVAC issues. About 4000 square foot house with multiple systems including two poorly installed ERVs. Summer house, so it is infrequently used. When I opened the covers on each ERV an oily substance dripped out. At first I thought it might have been water from uncontained condensation, but it had an oily consistency. I mentioned it to another rater and he said he'd seen the same thing in three other systems. The units still worked, but could it have been coming from the motors? Anybody else seen this? Anybody know what it is?