Absolutely the best heater ever!!! I am jealous, lol. Mine finally dies about a year ago and it still brings a tear to my eye. I had to fabricate a new wire mesh ball for mine after the original had burnt out. It helped extend the life of the unit by a few years, but it finally bit the biscuit.
Broke down and got the Mr. Heater, but liked the Focus 5 a lot more. Best $25 I ever spent on ice fishing!
Best of luck on the maintenance. Sorry I cant help with that tough.