Yes, PRESERVER is a Scrabble word!

Letter values in Scrabble US: P 3, R 1, E 1, S 1, E 1, R 1, V 4, E 1, R 1.

Is it a valid word?

PRESERVER is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a skilled worker who is employed to restore or refinish buildings or antique furniture
a cook who preserves fruits or meat
someone who keeps safe from harm or danger
rescue equipment consisting of a buoyant belt or jacket to keep a person from drowning

Also: life preserver, flotation device.