Re: bad oder from drain pipe
Floor drains should be equipped with a special device that slowly dribbles water into them so the trap doesn't dry out. If your drain doesn't have this, the trap has probably dried out, and that could be the source of your bad odor. Before cleaning, the drain may have been so nearly plugged that the odor was minimal.
I'm assuming that the A/C condensate line and water heater T/P valve drain into this floor drain (above the grating).
Normally, I'd expect the condensate line to keep the trap full, but in the wintertime the A/C doesn't run, so there's no condensate to refill the trap. If you live in a climate that is very dry in the winter, the trap can dry out enough in just a couple of days to let gases past.
Try pouring a quart of water down the drain every day, and see if that helps. That will keep the trap full and the sewer gases at bay.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.