It's High time I change the original (I think) deisel/water separator filter. this is the first filter from the tank. I was thinking of going with a Racor system with a 20 micron element. Does that sound about right? the other choices are 30 and 2 micron. 2 seems small for the initial filter. Thanks.
- Status
As controversial as varnish
There are endless battles about which size Racor to use as the primary filter. Racor does not recommend the 2 micron, but many people use it. I don't believe Racor makes a 20; your choice is 10 or 30. By the way, if your filter is Yanmar factory supplied, it could well be a Racor with a spin-on filter. That's what they've been using for at least the past few years.
There are endless battles about which size Racor to use as the primary filter. Racor does not recommend the 2 micron, but many people use it. I don't believe Racor makes a 20; your choice is 10 or 30. By the way, if your filter is Yanmar factory supplied, it could well be a Racor with a spin-on filter. That's what they've been using for at least the past few years.
Staged prefiltration ......
You probably have a small 2µM filter *on* the engine just before the lift pump (most yanmars do). It should be a small disposable filter inside of the small metal cannister with a bleed screw on the top. Typically each 'stage' that is upstream should be 5 times larger in 'rating'. So a 2µM should be prefiltered with a 10; a 10 with a 50, etc. Dont get carried away as these 'ratings' are only very approximate and 'really' dont reflect the true/'absolute' removal rating of the filter. The REAL answer is what is the present condition of your tank??? .... lots of sludge build-up on the walls, lots of bacteria growing in the bottom of the tank ... and how has the system behaved in the last year. If you have had NO problems, simply put the same 'rating' back in place. If you are having problems install a LARGER (surface area) filter, and consider to add a prefilter (5X) to the stage thats showing 'problems' .... or clean the tank. For less trouble, ALWAYS put on the LARGEST filter that fit into your present set-up. Filtration isnt something that one can be 'intuitive' about ... filters are not 'screen-doors'. Take this advice from one who is deeply involved in filtration engineering. When filters are plugging up ... what its telling you is the *system* is dirty .... then, go clean-out the system and get rid of the crap! BTW - if you are not running pressure/vacuum gauges on yuur filters .... think about installing them, as the gages will tell you WHEN to change the filters. There is NO need to regularly change a filter if the pressure/vacuum gage says you dont have to! Conversely if the pressure gage is rapidly changing over time ... CLEAN the TANK. ;-)
You probably have a small 2µM filter *on* the engine just before the lift pump (most yanmars do). It should be a small disposable filter inside of the small metal cannister with a bleed screw on the top. Typically each 'stage' that is upstream should be 5 times larger in 'rating'. So a 2µM should be prefiltered with a 10; a 10 with a 50, etc. Dont get carried away as these 'ratings' are only very approximate and 'really' dont reflect the true/'absolute' removal rating of the filter. The REAL answer is what is the present condition of your tank??? .... lots of sludge build-up on the walls, lots of bacteria growing in the bottom of the tank ... and how has the system behaved in the last year. If you have had NO problems, simply put the same 'rating' back in place. If you are having problems install a LARGER (surface area) filter, and consider to add a prefilter (5X) to the stage thats showing 'problems' .... or clean the tank. For less trouble, ALWAYS put on the LARGEST filter that fit into your present set-up. Filtration isnt something that one can be 'intuitive' about ... filters are not 'screen-doors'. Take this advice from one who is deeply involved in filtration engineering. When filters are plugging up ... what its telling you is the *system* is dirty .... then, go clean-out the system and get rid of the crap! BTW - if you are not running pressure/vacuum gauges on yuur filters .... think about installing them, as the gages will tell you WHEN to change the filters. There is NO need to regularly change a filter if the pressure/vacuum gage says you dont have to! Conversely if the pressure gage is rapidly changing over time ... CLEAN the TANK. ;-)
Tell me more
about the pressure vacuum gage. Sounds very interesting. Is there a web site we can go to for details, pricing, etc?
about the pressure vacuum gage. Sounds very interesting. Is there a web site we can go to for details, pricing, etc?
Gauge monitoring
Most Racor filter sets (housings and filter heads) have a port to which you attach a vacuum gauge. As a filter accumulates more and more debris the matrix of filter media will become clogged. A diaphargam pump 'downstream' works by 'balancing' flow rate or pressure (vacuum); either you get high flow and low pressure(vacuum) or high pressure(vacuum) and low flow. The gauge is used to monitor how the pump is 'straining' - the higher the vacuum indicating how full the filter is filled with debris and how hard the pump is working to overcome the accumulating restriction to flow. If you plot on a graph (you dont really need to) the life a of a filter will show that there will be a straight-line of total gallons filtered versus the gauge pressure(vacuum). When the filter 'starts' to become clogged and the plot just 'starts' to deviate from the straight line you can assume that the filter is 80-90% full of "crud capacity" and will soon totally 'plug' with debris (because there is no dirt capacity left). You dont want a diaphargm pump to be straining all the time with low flow and high presure (vacuum) as you will soon rupture the diaphragm and destroy the pump. The question becomes at what gage pressue do I change? the answer is: when you first install the gage, close the valve from the tank and run the pump to determine its maximum 'dead-head' pressure (willl be few psi). Change the filter when the vacuum gauge shows 80% of this value - simple! Actually a pressure feed system (pump at the tank) will allow better deposition of crud ON the surface of the filter media and will result in vastly longer service life of the filter. A filter in vacuum service forces the debris to deposit INSIDE the thickness of the filter media and you get much shorter life. The risk with a pressure feed system is that a tubing joint will vibrate open and you will risk filling your bilge with oil --- that makes the CG very unhappy. A vacuum system when it leaks, sucks air and shuts the engine down. The WORST thing you can do with a fuel oil system is put FINER rated filters in the line than what was designed .... makes the pump work VERY hard, and the filters will clog exponentially faster .... because in nature there are exponentially MORE smaller particles than larger particles. If for some reason you DO change out to a finer retention filter you MUST vastly increase the surface area of the filter (much BIGGER filter) to 're-balance' the system and not rapidly break the pump. On my boat I use a simple independent permanently installed recirculation/polishing system to do all the 'prefiltration' and water removal .... and havent changed out the 'final' filter in almost 5 years. Such a system uses VERY cheap and quite large retention rating filters and produces a resident particle distribution - in the tank - that is well into the 'sub-micronic' level; hence, NO challenge to the delivery fuel system filters - they just sit there as a 'guard'. hope this helps .... Fuel Filters are easy: intall the largest filter that will fit and use a gauge so you know WHEN to change.
Most Racor filter sets (housings and filter heads) have a port to which you attach a vacuum gauge. As a filter accumulates more and more debris the matrix of filter media will become clogged. A diaphargam pump 'downstream' works by 'balancing' flow rate or pressure (vacuum); either you get high flow and low pressure(vacuum) or high pressure(vacuum) and low flow. The gauge is used to monitor how the pump is 'straining' - the higher the vacuum indicating how full the filter is filled with debris and how hard the pump is working to overcome the accumulating restriction to flow. If you plot on a graph (you dont really need to) the life a of a filter will show that there will be a straight-line of total gallons filtered versus the gauge pressure(vacuum). When the filter 'starts' to become clogged and the plot just 'starts' to deviate from the straight line you can assume that the filter is 80-90% full of "crud capacity" and will soon totally 'plug' with debris (because there is no dirt capacity left). You dont want a diaphargm pump to be straining all the time with low flow and high presure (vacuum) as you will soon rupture the diaphragm and destroy the pump. The question becomes at what gage pressue do I change? the answer is: when you first install the gage, close the valve from the tank and run the pump to determine its maximum 'dead-head' pressure (willl be few psi). Change the filter when the vacuum gauge shows 80% of this value - simple! Actually a pressure feed system (pump at the tank) will allow better deposition of crud ON the surface of the filter media and will result in vastly longer service life of the filter. A filter in vacuum service forces the debris to deposit INSIDE the thickness of the filter media and you get much shorter life. The risk with a pressure feed system is that a tubing joint will vibrate open and you will risk filling your bilge with oil --- that makes the CG very unhappy. A vacuum system when it leaks, sucks air and shuts the engine down. The WORST thing you can do with a fuel oil system is put FINER rated filters in the line than what was designed .... makes the pump work VERY hard, and the filters will clog exponentially faster .... because in nature there are exponentially MORE smaller particles than larger particles. If for some reason you DO change out to a finer retention filter you MUST vastly increase the surface area of the filter (much BIGGER filter) to 're-balance' the system and not rapidly break the pump. On my boat I use a simple independent permanently installed recirculation/polishing system to do all the 'prefiltration' and water removal .... and havent changed out the 'final' filter in almost 5 years. Such a system uses VERY cheap and quite large retention rating filters and produces a resident particle distribution - in the tank - that is well into the 'sub-micronic' level; hence, NO challenge to the delivery fuel system filters - they just sit there as a 'guard'. hope this helps .... Fuel Filters are easy: intall the largest filter that will fit and use a gauge so you know WHEN to change.
- Status