Porta Vault is just the name Hamilton gave it
True portable vaults are exactly what the name implies. Small bank branches who didn't need a large walk in vault, but still needed the security could buy what amounts to a real bank vault door installed on a very heavy body. Although most of these weigh between 8,000 and 12,000 pounds, they are considered portable.
A locksmith said I should have the lock serviced.
They are correct. If you have a safe tech available in your area, you should use them first. A locksmith with safe and vault experience should work if a safe tech isn't available in your area. You should ask about their experience, because a locksmith without safe and vault training can be just as bad as any other do it yourselfer.
What does that mean? It has the S&G dial, do they need to be serviced often? Thanks for the help!!
Locks on safes and vaults get serviced just like any other mechanical device. Consider it similar to changing the fluids in your car.
The lock is usually torn down, inspected for wear, relubricated, and reassembled. On a 20 year old commercial safe, an original lock may be worth replacing. In commercial use, locks should be serviced once a year. In residential use, once every 5 years is typically fine. Lack of service is a leading cause of lock outs for mechanical locks.
If the safe has a time lock, have your safe tech disable it. Time locks are expensive to service, and are very finicky.
These safes are very expensive to drill open (what you're paying for the safe isn't far off from what it could cost), so you want to make sure everything is working properly before you use it.
