The long story: We have hot water baseboard heat which has always been less than satisfactory. Last year I installed a ps (which has a switch) to power pc cooling fans in 7 of the baseboard units which has greatly increased the comfort level while decreasing the utility cost. I have it wired so the fans come on when the hot water circulating pump starts. I've used all the 12v leads on the present ps. I have 8 more heat exchangers that need the fans installed but can't figure how to make the ps always hot so it too will be dependent on my pump cycles.