Yes the burner tray comes out. Its not difficult. Shut off electric and gas. Take out 4 allen screws on top of gas valve that connect the gas valve 90 to the hard pipe. Remove the burner tray screws and disconnect the moles connections. The entire unit slides out. Then remove the pilot assemble screws once its out and replace. You might as well remove the top panel of the boiler jacket and brush down the heat exchanger then vacuum the combustion chamber before sliding everything back in.
you can remove the front burner cover and disconnect the thermocouple at the gas valve and then get down and reach in an loosen the nut that holds the thermocouple in place and unscrew it and then pull it out and replace it.
The question is why are you changing it, has it been tested by taking millivolt readings? See RESOURCES ABOVE THEN LIBRARY THEN TIM'S CLOSET FOR HOW TO DO THAT.
As for replacement it depends on the pilot but a Honeywell Q 340 will usually cover most applications, they run as far as durability and performance right next to a Johnson (now Baso Gas Controls LLC) Husky. If you are having issues with frequent changes a Baso K16LRA corrosion resistant, high temperature thermocouple will take care of that.
This post was edited by an admin on March 31, 2014 12:18 PM.