I noticed my hydronic floor heat was no longer heating, and the circulator pump was extremely loud. This system was new in 2009 with one valve, pressure tank, and electric boiler replaced in 2021.
It sounded like it was likely a bad circulator pump so I ordered a new matching pump - Taco 0011-BF4 - I ordered a Taco 0011-Bf4-J to replace it.
The pump came today so I removed the old one - first shutting the valve above and below the pump. The pressure tank says it is charged to 15 psi so I wasn't surprised when I heard a small hiss when undoing the bolts for the old pump. But after that I expected a drip, and got nothing at all - taking the pump off it is completely dry.
Here's a photo of the whole system (hot water heater (hydronic only) to the right):
Shouldn't there be water in this section? (I last tried turning it on about 48 hours ago) If so, what could cause it to be dry? I don't see any valves closed other than the two I closed to remove the pump - but admittedly don't understand it all. I've ready of air trapped in the system but was under the understanding that the supervent at the top should prevent that. Am I missing something?