Welcome! Here are some tips for using this forum.
I have a Lochinvar boiler that has started throwing an error "lockout - outlet temp diff"
Boiler repairman has replaced both sensors and on Friday the main control board ($800) and it ran fine Friday night, Saturday night, and this morning I get the same damn error. I'm now into this repair for $1500 and getting the same error. Any Lochinvar experts got any ideas?