I have a State Censible Mod. # PRV 40 NOVT1, 40 gal. Ser #K9691712. THe problem that I 'm having is the vent motor doesn' t shut off at all I checked out the unit and i see were the wire goes from the disc. switch to the gas pressure valve and then to the air valve, and the wire is on the com. side of the limit it it looks to me as thou as soon as the gas vale opens then the fan comes on. I looked for a temperature limit but didn't see any on the diagram.