The manufacturer may have a parts list showing if this piece is separate from the tank.
For a second opinion as to repairs, find a machine shop that makes house calls.
You can modify a $16 water level detector to alarm when, and if, this thing starts leaking.
If this boiler can be considered "HVAC equip.", 83% have lasted longer than this.
If it's comparable to a gas WH, 81% have lasted longer.