Originally Posted by Bigd2
The unit takes a Garber Type "R"
NAPA 3109 (~$9) Use them all the time.... I've got over 4,000 hours using the NAPA filters (which is made by WIX). Use the number above or have NAPA cross part number "R" just for fun, it works!
Roger Berke has excellent prices on filters and complete annual service kits (if you are replacing the filter it is a good idea to replace the nozzle as well).
RV Hydronic Heater Repair - Home
BTW If you go to a oil heat place they have the Garbers in spades, it's the standard oil furnace filter used in stix-n-brix.