Welcome to the board!!
Sorry I don't know what a CV-VUB-81 is but here are few things to reduce the amount of electricity it takes to keep the soda's or whatever cold.

Keep the machine full.
Make sure there is good airflow through the vents.
Clean dust/grime off of any fins or fan blades.
Make sure main door and bottle door seals are good.

Creighton



 

another trick to help cut the cost of running a soda machine iif it's a lightup sign model, turn off the sign or just remove the lamp & reconnect it when you are entertaining, you can also install an appliance timer (rated for the machine) & have it shut off in the evening & when you're not around during the day. and as stated above, kepping the machine full, clean & the coils free of dust-bunnys will help the machine run effiecently , also don't obstruct the air flow if the machine has the condersor coils that vent to the back of the machine, (like a Vendo V39. if your machine is the kind with a coinmech heater. you can disconnect it. this heater will draw current about 1/2 an amp & it isn't needed on these hobby machines that won't see outside service in the winter again. (this heater is often found on older round-cornered models like Vendo 56,81,V39, etc.)

when I check a machine, I put an in-line Amp meter on it & make a note of the current draw while it's running, & then you can compare that reading to the stated amps listed on the machines ID tag. if it's higher than the tag says. you could have a compressor pulling too many amps of current , which could mean it's getting ready to go bye-bye..just a thought