Re: Off set is for a sensor
The 'center' one is not a plug, it is what you put a wrench on and turn to remove the lower assembly. It's basically the head of a long bolt that extends up through the filter and screws into the head assembly. You don't drain water out of it, or anything else for that matter, because it doesn't come off. You can use a strap wrench of some kind on the lower assembly body, but personally I wouldn't risk it except as a last resort, because the lower bell is pretty thin aluminum and could crush or deform pretty easily. When you get the lower assembly off, there will be a rubber gasket trapped in the rim of the upper assembly that you will need a pick, awl, or some kind of sharp pokey thing to remove. You should get a new one with the R11T element that the Racor 110A uses. The 'offset' plug on the bottom is the one that you can remove to drain water and debris from the filter element. The vent plug is on the side of the upper assembly. There's a rumor that the 110 doesn't filter water, but the spec sheet for the R11T element claims that its "aquablock technology removes water" from the fuel. Which I assume you drain out the bottom. From the offset plug.
