Investors and rental owners

Yes if you have UCC for a class 8 asset (Equipment/Appliances) then enter the lesser of original ACB or its current market value determined at the time of purchase. Do this only if the value of the Class 8 item is stipulated in the purchase agreement. If no value was discussed then it is likely the value (depending on age) is now zero and proceeds would be recorded as $1.00. Most Class 8 items if older will have no (or minimal) value on sale.
The bigger issue would be with any Class 1 asset and prior CCA taken. This may result in Recapture and income reported on the T776 from the sale.