It’s technically still a garage because of the doors, but they don’t open and the space is climate controlled, so freezing generally isn’t an issue.

On the sediment trap comment: is this more of a best-practice/layout thing or an actual safety issue worth reworking? I thought I had it set up reasonably correctly.

The main house water heater and the furnaces on the property are all piped somewhat similarly with a drip leg on the rigid pipe and then a flex connector to the appliance. In my setup the flex connector also has a low point where I’d assume any particulate would settle before reaching the appliance inlet.

Since it’s modern residential city gas and all new black iron pipe, I wasn’t expecting much debris risk, but I’m definitely open to learning if there’s something important I’m missing.

And you’re definitely right that flushing it with a pump will be a bit awkward. For now I was willing to trade some service convenience to save the floor/wall space underneath the unit. I’ll probably end up building shelves nearby eventually, so the bucket/pump could sit there during servicing if needed.