I have an ev 150c upright freezer and the suction sealing of the door works intermittently.

SOURCE: new freezer has bad door seal

it often works to warm the seal with a hairdryer and reshape it

SOURCE: Kenmore freezer

if the gasket isn't torn and the gap isn't caused by a door hinge problem you might try putting some vaseline on the door seal. If that doesn't help you may have to replace the seal.

SOURCE: Sears Upright freezer-the door does not have the suction anymore

You may need the hinge adjusted or a new door gasket but you might first try putting a layer of vaseline on the gasket. If none of those things help the problem is probably other than the door seal.

SOURCE: Kenmore commercial upright freezer not sealing well - thawing

If the door seal does not seal completely, replace it. This is very important for freezers.
Contact Rick at Restaurant Parts and More.
\1-888-814-1110. He can most likely get what you need. Just have model and serial numbers and he'll do the rest.
Home Depot and Lowes is a definite no.