Is there some secret to getting the faucet running from the tank under the sink? No amount of vigorous pumping seems to have any effect!
I got a response via email from Zebra RV accessories:
There must be no air being "sucked in" from the city water connection. Make sure that the city water fill is securely capped and that all its connections up to the pump are secure.
I guess that means that the city water hose hanging from the faucet must either be connected or capped.