I put in this water heater several years ago. [As a favor to a friend for his wife and step-daughter, now a FWPD with a bad attitude] I was gritting my gums the whole way home (4 miles).
A EweToob search for "4 blinks water heater" brought up a billion hits.
Who else does Honeywell work for? Defense industry, and Joe MFing Bidet.
I'm pretty unhappy about that water heater thing. I'm really unhappy about a former Marine/Civ firefighter dropping dead. 2 kids/wife, 48.