Hayward Heater transformer failed - H300ed1?

[InheritedAnthony]

Hi!
This forum has been excellent at helping me get the old pool I got last season up and running, and I was hoping I could breath some life back into my old gas pool heater before it truly bites the dust.
It's a Natural Gas Hayward H300-ED1, configured to use 120v. It's on a 20A Breaker.
See attached photos.

It worked fine until a short storm over the weekend and this morning showed no signs of life.
Opening it up I checked that the power leads from the breaker and they showed power.
Since not even the system status LED was going on and I did not detect any low voltage on the boards, tested the transformer, and could not detect any voltage on the LV side.
Testing the terminals on the transformer for resistance showed only .25 between the not used Orange and the white. All other combinations on the HV and LV side did not return any resistance.

Is this as simple as a blown transformer?
If yes what is the correct one to replace this?

Is there anything else I can check on the circuit board or other components to see if perhaps something else caused the transformer to go?

Any help would be appreciated!!

 

[InheritedAnthony]

Followup Questions I had when looking for transformers:

1. Why is there such a dramatic price difference when I look up transformers with the same specs, vs when I look for Hayward heater transformers?
   Class II transformer, 40VA, 120/240 primary, 24v secondary
   For example this $20 one vs this $80 one vs this $120 one?
2. Is the "1/40c" Current ratio important? most replacement transformers do not specify it?
3. Does this whole control system run on 24AC? I'm just checking as I don't see any DC on the diagram I attached. Mostly just curious.

 

[InheritedAnthony]

Reposting for Visibility, if that's OK?

 

[ajw22]

Since @swamprat69 is back maybe he has some answers for you.

 

[swamprat69]

It appears that the higher priced transformers reflect the Hayward markup. 40C is the ambient temperature rating for most non-oil jacketed transformers. Nothing wrong with using a non Hayward transformer with the same ratings as the original. I do not see an insulation rating on the original which would conform to this chart

 

[InheritedAnthony]

It appears that the higher priced transformers reflect the Hayward markup. 40C is the ambient temperature rating for most non-oil jacketed transformers. Nothing wrong with using a non Hayward transformer with the same ratings as the original. I do not see an insulation rating on the original which would conform to this chart

Thanks!
I swapped it out with the amazon one I listed and it fired up nicely!
Hopefully, I get another few years out of it.

Do I need hi-temp or damp-rated wire nuts for the connections inside the heater?