Sorry I don’t have the exact model but I assume they all mostly function the same. I have a brand new heater that was installed in September and has been an issue from the beginning. Unit fires when turning on first time for the day and reaches temp. Then turns off and when spa cools and heater needs to turn on, it won’t fire. It never fails to fire on the first time for the day. If I give it some time to chill, it’ll fire up and stay lit until reaching temp. I don’t think it’s a propane issue because I would think it would either work or not or at least sometimes not work on the first attempt of the day. I should also add that when it does fire, I smell gas right before it fires. When it doesn’t fire I smell no gas. Is it a gas valve issue?