If you are selling your primary residence then no issue. If you move to the investment and then sell it later then the 4 rental years are counted towards capital gain when you sell that one (ratio against the years you lived in it as a primary resi).
Be aware of what you can claim against the investment. Lots try and claim all sorts of repairs as deductions for the year but it has to be like for like, no upgrades allowed.
Have a chat to a Fin Advisor you know - lots on the internet to point you in the right direction on the rules.