Looks like the advice about filling the tank more-slowly did the trick. That or fiddling around and swearing a lot did the trick.
I refilled the tank slower until water was coming out the air outlet and then tried again. took a minute, but eventually the pump started pumping water, filled the HW tank and gave me both hot and cold from the faucet and shower.
I'm pretty sure my FW tank was full when all of this started, but I'll just go with what works now and call it a day. Thanks for all the fast responses