So I have a reverbaray XTS20-75N tube heater that is giving me a headache trying to diagnose, the induction motor comes on but nothing happens after that, I checked the ignitor for power but it never gets 120v, so I checked the pressure switch tube to the exhaust side for debris and found non, after fighting with it for awhile to get access to the internals to check the pressure switches and hoses, I was informed by tech support the only way to get into the thing to check the pressure switches was from the top, which the thing is mounted 4” from the cealing, which means I had to disconnect the gas,power, and tube and drop the dang thing to get access to the internals...stupid design considering these things are usually 12-16ft in the air, anyways now that it is on a bench and i have hard wired to a plug, and have checked all the hoses for vacuum leaks and cracks, checked continuity of the switches to make sure NO pressure switch is not stuck closed and NC pressure switch is not stuck open, I dont have an actual pressure switch tester like the fieldpiece one with the internal pump, so how do I tell which switch is not opening or closing and If its the switches or the ignition module, because tech also informed me you cannot run the thing with the top cover off because it seals the exhaust side and intake side. So how the heck am I to check for voltage/continuity when its running to see which component isnt working?! Any ideas or do I just order both switches and a module to be safe and call it good? I hate doing that but this thing is really being a thorn in my side do to engineering...