i am very new and just flushed system from antifreeze, i pulled the grey and black valve, but my question is, how do I know if these valves are open or closed. they don't seem to push back in. also, what is an inline filter for water hose? i had low water pressure. wasn't sure if i needed water pump on or off, i used hose hooked up and left it on. i was told to take all filters off shower and sink faucets and use an inline filter on hose? is this correct and is that what i ask for, "inline" filter? also do u think i need a plug in voltage meter to keep an eye on my amps. is it true, it shouldn't go below 105, if it does, do i turn off something, like air cond.