Can you smell what's cooking?
I bet that machine still has the new dishwasher smell to it!
This machine will last you at least 30 years with just reasonable care. Just start collecting some spare parts for it while you can. Get yourself 2 shaft seal kits and at least as many washarm supports which include the fine mesh filter housing. A spare washarm would help too.
These machines were produced for a good number of years.The last ones made by Whirlpool, but with the Hobart design just like you see, it had the bituminous sheets covering the whole tank, top sides and most of the bottom and inside the door then a layer of fiberglass. These were far quieter than the same machines built by Hobart. If yours is a true Hobart unit,you can buy some dynamat and wrap the tank the same way and really insulate it. I was surprised at how much quieter ours is than the 18 it replaced(the 18 I had used a 20 series tank).
The 21 series was produced from Approx April '84 thru Feb of '89.
In my opinion, it was the best designed machine ever made by Hobart and cleans better than anything they ever made before or since!
I AM partial to the 18's like most of the people on this site because of its cleaning ability and the multiple prewashes and washes as well as the 2 or 3 after rinses it provides. The short cycle provides 2 after rinses and all other full cycles use 3 rinses.And does it all faster than the 21.
The 21 provides basically a purge after the 2nd wash and then one final rinse.
The fine filtration system and the mini garbage sisposer in the 21 is unsurpassed by anything before or since its use in a domestic or commercial undercounter dishwasher.
There should be a small date code on the front cross member near the water inlet valve. It will give you the day and year the machine was built. If it is an early production unit, it will have the round shaped Hobart built reversing motor. If it is a slab sided motor, it is the Emerson built motor that was used in later models.
(Hobart still uses the 18-20 series motors and pumps in their current production SR24 series dishwashers). Too bad it wasnt the reversing style pump..we would have had an alternate source for replacement parts for the future!)