My fiance's house has a solar collector heat supplement system that we believe was installed in the 70's. We have no paperwork on this system, and haven't seen a label or insignia that would tell us what brand it is.
The collector is wedge shaped and is on the roof of the attached garage. There is a single duct that blows air into the kitchen/living room area. It works very well, and on sunny days the main furnace does not run much, even when the temps dip below zero. The bedrooms get pretty chilly, but who cares, since it's daytime. The problem is that when it first kicks on, there is nasty odor - sort of like garbage. It doesn't smell like mildew - I know that odor well. You can even kind of taste the odor - if you know what I mean. The odor goes away after about an hour or so. It only happens when the solar hasn't run for a few days, like when it has been cloudy.
Is anyone familiar with these units? We feel like he has the only functioning unit around here. He doesn't want to stop using it, because it saves him a fortune every winter.
Sounds gross but it is possible that mice/rodents got into the duct, made a nest and did some "business" (pooped) in there. Somebody/exterminator? may need to open the duct and inspect it. Have watched Mike Rowe from Dirty Jobs and sh*t like that happens.