My heater stopped working the other day and from what I've learned, it's the flame sensor. The exhaust fan comes on, glow plug lights up, then burners ignite but go out after about five seconds. This keeps on repeating. My unit has a smartvalve with a combination glowplug/flame sensor. I was cleaning the sensor and while doing so, I broke the glowplug. So I replaced the flame sensor in my arcoaire furnace but the burners still will not stay lit. Does anyone have any ideas or know of ways to test the smartvalve? Thanks in advance.