Kevin a few things. Make sure that the tank is sealed. Meaning, is the fill point closed off, is the city water inlet capped? Do you have a winteriztion system? Have you turned it back to normal use and made sure its capped off? Is your water heater closed too? Any of these can allow your pump to lose prime.
If you're getting 30 gallons I would think it's closed off properly. Dealer might be able to assist you over the phone too, my dealer got me in and out 2 days before a trip and installed a fridge even, they can step up sometimes and shock you, it's worth a call.
Two Wire Fox Terriers; Sarge & Sully
2007 Winnebago Sightseer 35J
2020 Jeep Gladiator Rubicon