I bought a new 5 brick ventless heater two years ago and just now got around to having it hooked up. It works great on low and medium. But when turned on high, where all 5 bricks are lit up... it works fine for about 3or 4 minutes, then shuts off.... pilot light goes out. It relights just fine.
It doesn't do this on low or medium, just when turned on high. Is it an oxygen flow problem? Or a heat sensor?
Any advice and/or help is greatly appreciated.