Pool will be closed tomorrow. Our lines are blown out, because we're in Minnesota. Once that is done, is it possible or advisable for me to take any of the pipes apart? I'd like to check the pipes into our heater. It consistently refuses to fire because the pressure isn't high enough, even after I've backwashed and cleaned the filter. I'm wondering if there's some debris that's blocking the flow to the heater. We've replaced every part on the heater; it should work perfectly. But the pressure switch doesn't seem to let it fire.