I am a very strong trouble shooter, but I can’t get this boiler running. Please help me! We have three 15 year old boilers in a penthouse serving a make up air unit. The boilers are intermitently locking out on pilot failure. We have checked the grounds, replaced the pilot assemblies, tested the gas pressures, and had the gas company come and test the building pressures and replace the regulator. I had two boilders running overnight and one locked out on pilot failure this afternoon. We can reset the boilers, but not know which one will continue to work. HELP ME!