Most of my work is on furnaces, don't do a lot of fireplace stuff but some.Went to look at a Napoleon GDS28 that is shutting down. the pilot will light, turn on wall switch and main valve takes about a minute to open? will go for about 30 seconds then the pilot shuts down, main valve snaps closed about 10 seconds later.

We currently have a real cold snap here in southern Ontario so real busy, I just popped in to see if it may be just a T-couple or something easy, not the case.

My question, does the spill switch shut down just the pilot or the main as well?

Any suggestions are appreciated.