Are you allowed to deduct the $1000 from $1400?
No, you can only deduct from the $1,400 of rental income those expenses that are related to the rental activity.
If paying a mortgage you could deduct the mortgage interest, and you could deduct insurance, HOA fees, property taxes, repair costs, etc.
You'd also depreciate the condo and deduct that expense from your rental income.
It could be a financially beneficial situation still, depending on how much it costs you per month to live in the condo, but it isn't likely a good way to increase cash on hand.
Edit: I did not notice the Canada tags when answering, in general the answer holds true, but it'd be capital cost allowance instead of depreciation expense and appears to be optional.