Question about garage door torsion springs
I know this topic has been covered fairly well, but I have a situation that appears to be unique.
I have 3 torsion springs on a double garage door.
Home was built in 1980 and the third spring looks like it is "original" (equal patina on all the metal parts involved). Recently, I have been having issues with the door with turned out to be unrelated to the springs, but I am concerned because the door is so heavy.
Ultimately they will break (have to eventually). The door is very heavy ...probably 400lbs without the springs (older wood/composite door with thick 3/4" cedar siding on the front). The thing is a bear to get up now and the springs are supposedly "working".
So here is my question: if and when I replace these springs, should I revert to 2 springs or stick with 3? The door is a pretty standard double garage width, so there is no extra width, just extra weight.
Is the 3 spring design adequate for the door or is this a bad idea? This isn't a question of whether the springs have the right torque for the door, but rather if it is even possible to get good performance from a 3 spring design.
Anyone else ever seen 3 springs on a residential door before?