Now that the heater is fixed... what the heck is this thing (Sorry, no pictures - maybe Wednesday night):
On the return from my friend's pool, he has a jandy valve on the return from the pump/heater/etc...
This jandy-valve output normally is "hard-set" to his in-floor cleaners, the other output sends water to what looks like a skimmer basket in the deck next to the side of the pool (it is not a skimmer) that, when on, blows water through this to a single return output in the pool.
Lifting the lid, it has (looking top-down)
- a pressurized clear on lid (could not get it off)
- it looks like a floating wier underneath the lid, and under that, a basket...
I think it is clogged pretty bad, as almost no water goes through it when the valve is set to this thing (and filter pressure goes way up while it's routed that direction).