This has me baffled. I've had the gas checked and was told it's ok. Checked and replaced just about everything in this 1 year old LRZ400, and I still can't keep the heater lit for more than 5 minutes. It shuts off, cycles a couple of times then the above fault message appears and it shuts down. I've checked for blockages, cleaned every darn thing in the system, but no luck... Help!! and thanks in advance.