katysdad wrote:
Check the propane detector. Most motorhomes have a LP detector that will shut off the propane by use of an electric valve just downstream of the regulator if fumes are detected. Most also take several minutes to warm up and allow power to valve. Either could be defective. Even if not, if over seven years old both pieces should be replaced as a set.
That would be my first thought. If they plumbed the external tank in after the tank regulator they probably bypassed the electric solenoid connected to the propane detector.