[davepl]

Does anyone know offhand which direction these work?

Does the weight pull it open or hold it closed?

Does the spring pull it open or hold it closed?

I assume they work opposite each other and the spring is thermal, but I don't know which does which job.

I'm trying, in the end, to figure out what happens when your heat riser gets old and maybe the spring gets weak. Does it fail to close or fail to open properly?