Laars/Jandy LX400 sensor stud assembly replacement

[DKLO]

Hello,
I have an 8 year old Jandy LX400 heater. Water is penetrating high limit switch cavity and corroding switches. I had the brass sensor stud assembly replaced by a gas tech 4 years ago and have to do it again.

I want to do it myself this time and have the pieces. I have removed top shroud, and header bolts(8). I have to take off header and it is stuck on really well. How do I back it off to access stud assembly?
I'm worried that by trying to forcefully back it off I may crack aluminum (?) piece on which black header fits. Perhaps should I use a block of wood placed on edge of header lip and tap it out?

Please help and thank you in advance!

DKLO

 

[ps0303]

The pieces are either stainless steel or polymer(Plastic). It should just pop off with a good pull.

It's a shame you have to replace this again but unfortunately I see this alot on these units and to me if it happens alot, it's a design flaw. At no time should you have to replace a part a like this. There are so many other units out there that this doesn't happen on.