You mean PSI low? I run my forced air at about 5-7, give or take, I think non forced air require higher - like around 10-15 psi.
Tempering is another beast - you can temper with it, but depending on what you need to temper, you might need a more controlled environment or a sharp eye.
Example is - when tempering a knife, you usually temper a high carbon knife (1095) to 400-500 degrees for 2 hours. Twice. With that, I use a toaster over that I actually put an extra electric burner inside to get up to 475… I don’t watch it.
When tempering a hammer made of 1045, how I’ve seen it done, is you have a stack of fire brick that you pile in a certain way so that there is a 1" slit opening or so up on top. You put the hammers ontop of that stack, with the eyes right over the slit. Watch carefully as the temper colors draw, as soon as the hammer faces are straw to dark straw you toss it in water.
Some other people don’t get as technical. My gas forge can’t get down to 500 degrees, maybe if I had a different burner I could but I couldn’t, so I really don’t use the forge for tempering. Others very well may though.
I don’t think you can ever ask too much from the tool if you can figure out new and different ways to use it I know the guy who makes hammers up here in Minnesota (Nathan Robertson), I see him use a pile of bricks for getting forging temperatures, as well as annealing, heating, and tempering.