I have a Raypak 2100 heater that won't ignite. Worked fine last year, I replaced the board last July. It turns on fine now, sparks, but then pilot doesn't ignite. It's as if it isn't getting gas. Valve is on, seems like orifice might be blocked. My question is how to get to the pilot to disassemble it? Do I need to take out the whole burner drawer? The pilot is behind a bracket that is I can really get to to unscrew. I realize this heater is getting to the end of its life but trying to get another season or two out of it. Thanks!!