excess gas pressure
had good pro out to look at Lennox hi eff. 92% about 15 year old smallest they made at time , furnace. It has probably been used 10 of those years. pro says it has froze, which it has,,,,have to rip it out and replace it, cant fix it.
MAIN problem is excess gas pressure. "Before the gas valve about 7 water column inches,,,after gas valve it reads 5.9 on his digital meter. Says its adjusted all the way down. He even took the spring completely out and it didnt even change after pressure at all. What would cause valve to not regulate pressure? If its stuck or bad would it not be cheaper to replace gas valve than whole furnace???
When it turns on for first time after being off for awhile it sounds like 2 bricks being slammed together,,,,very loudly. Is my ONLY option complete furnace replacement? tech said furnace reliability is questionable