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3/8" or 1/2" Oil Supply Line?

BinDerSmokDatBinDerSmokDat Member Posts: 23
I'm replacing an old 330 gallon outdoor tank with a new 275 gallon tank.
The current fuel line comes off the tank with 3/8" bare copper fuel line, through about 14" of dirt (about 6-8" deep and then about 6-7 inches to wall) then through a hollow block wall, with hydraulic cement sealing the hole the line enters. The line runs along basement rafters, about 40' between tank and boiler with a Westwood cartridge filter installed. The boiler is a Weil-McLain Gold WTGO circa 1997-98 vintage.

I want to run plastic coated fuel line, ideally through some sort of conduit/plastic piping at the wall to protect it from the masonry and dirt, adding a vertical coil outside to allow for any expansion/movement.

I've read some recommendations to use a 1/2" line, but everywhere I look tank valves and Westwood fittings are all 3/8". For example standard fuel tank valves are 1/2" x 3/8" and I can only find old style bowl types with 1/2" fittings for industrial uses.

What is the advantage to using 1/2" line? Is it possible to find 1/2 x 1/2 valves and filter housings to use 1/2" lines? Or just stick with 3/8" as it necks down anyway?
Weil-McLain Gold P-WTGO-4 DOM 07/09/96, rated 1.25 GPH
Beckett AFG Burner DOM 05/23/96, F4 Head
Delavan 1.0gph 80° B solid nozzle
10 Micron Westwood spin-on


  • STEVEusaPASTEVEusaPA Member Posts: 3,481
    edited September 3
    Is the entire run gravity down to the burner? If not, can you post a sketch with dimensions?
    You may need an oil safety valve also.
    If it’s all gravity, I would have a firomatic valve right where it enters the house (code).
    Then I would do a general filter and a spin on. Then continue oil line across joists, drop to boiler.
    Depending on total drop, I’d either put an OSV right after the filters or at the drop to the burner at a maximum 3 ft above boiler, then another firomatic.
    In this scenario, 3/8 would be fine. Depending on all your dimensions, if there is lift involved then you may have to either bump up to 1/2”, or maybe a 2 stage pump. Again would like to see a sketch first with dimensions.
    Expansion loops outside and at the burner are a good idea and code.
  • BinDerSmokDatBinDerSmokDat Member Posts: 23
    So the fuel flows all by gravity downhill to boiler.

    330 gallon tank> 1/2"x3/8" bottom Firomatic valve at tank> about 30 ft 3/8" copper line > stem valve shut off> 4ft feet of 3/8" copper to westwood cartridge filter> flexible braided westwood line to burner. No check/OSV valve.

    I don't recall a firomatic inside of house, but I'd have to double check. Unless the stem valve has a built in fire fusible, but I don't think so, just a regular ol' red handled stem valve (rated for oil of course.) I always thought that was weird, a firomatic outside with little chance of a fire with a brick house, steel tank on concrete pad with nothing around to burn, but no firomatic in house with combustible stowed in basement and flexible supply line to boiler.

    Current system has been in place for the 20 years I've lived there, no issues.

    Weil-McLain Gold P-WTGO-4 DOM 07/09/96, rated 1.25 GPH
    Beckett AFG Burner DOM 05/23/96, F4 Head
    Delavan 1.0gph 80° B solid nozzle
    10 Micron Westwood spin-on
  • ronron Member Posts: 140
    for an outdoor tank an advantage of 1/2" over 3/8" line is the larger line will be less likely to have the fuel oil gel in cold climates. for outdoor and dealing with cold you want to maximize diameter wherever possible because the smaller the diameter the easier it will chill and fuel will gel when exposed to cold moving air. Also you can do longer runs with 1/2" line over 3/8". You can reference the total length and maximum lift from the suntec pump manual. Generally for whatever extra it costs for 1/2" it kinda rules out any possibility of oil feed line being too small in most residential applications.

    1/2" stuff very common

    mip x 1/2" flare very common:

    the common general 1a-25b oil filter housing has 3/8" threads because it's the small guy. But ideally u don't want that outside or near cold, u want something like that near the boiler in which case you use a 3/8 MIP to 1/2 flare. Or get a larger 2a general filter housing that has the 1/2 threads if you prefer. I prefer the filter at the tank keeping clean oil in the line on way to burner, and like the gar-ber spin on stuff. if u have an above ground outdoor tank in cold climate then be mindful of being able to service such a filter at the tank if it does gel and block.
  • STEVEusaPASTEVEusaPA Member Posts: 3,481
    You need a firomatic right after the fuel line enters the building, by code.

    1/2" & 3/8" will gel at the same time. If it's that cold, or you're using a heavy bio mix, treat the oil for moisture and lowering it's pour point (which you should do anyways). Treat the tank, stick with 3/8", as long as you don't exceed 6" of vacuum, which you can check on your current system.
    No filters outside, of course.

    I'd do it the way I described in my first post. The only judgement call would be the drop to the burner.
    If you bleed the oil line (burner not running) and check the line at the burner with a pressure gauge and you get 2 psi or more, I'd put in the OSV at the maximum 3' height on the drop (that's 3' max from the burner). If you are not reading 2 psi or more, I'd put the OSV after the filters. Then you are protected from the OSV to the burner, should the oil line leak, from dumping the entire contents of your oil tank into the basement.
    No check valves.
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 6,109
    What burner is on this? Residential or commercial?
  • BinDerSmokDatBinDerSmokDat Member Posts: 23
    Thanks guys that's a lot to digest so let me start with...

    I'm the homeowner and the entire set-up I'm discussing is residential.

    For the last 20 years I have used DieselKleen Winterizer/AntiGel with the first big fill after summer and any mid-winter fills.
    (Yeah, I know it isn't for heating oil.)
    In 20 years I had only one iced/gelled line. We had sustained temps in the 0's for a few days, so tough to say if it was gelling, water or sludge kicked up. The supplier, who was also providing service at that time, came out did an emergency call and got it running. It died again a few hours later at 3am. I took a hairdryer to the outside portion of the fuel line, thawed it and blew back with compressed air, solved problem. I added more DK antigel the next day and never had a problem again.

    I have also never been told by a tech that I have any kind of fuel starvation issues and when I have bled the fuel line to see what is coming out, it flows pretty fast, faster than the burner can burn it, i'm sure of that. I have gauges, I'll see if I can attempt the test STEVEusaPA, but right now I don't think I have an issue with fuel delivery. I think that also says I don't need a filter at the tank, but I might consider one just to keep the line clean, but if I do it will be a spin-on, I hate changing the felt filters.

    That said, while I'm doing the job, it sounds like I might as well upgrade to 1/2" along the way.

    So if I add "Firomatic right after the fuel line enters the building, by code"...

    330 gal vert tank> ???? > 1/2 inch copper line with horizontal loop then subgrade through basement wall (2-3 feet) > inline 1/2" firomatic fusible> 35'-40' upgrade existing ball valve to 1/2" > upgrade about 6' of line to 1/2" > OSV valve >leave existing 3/8" Westwood spin-on and call it a day? Or do i need to go 1/2' all the way to the burner?

    Also for my "????" above, what is the recommendation for coming off the tank since I won't be using a bottom Firomatic? 1/2 thread 90 > ball valve > 1/2 MIP to flare?

    Also when I run the line through the hollow block wall, what is recommended? Electrical conduit? PVC pipe? I was thinking a pre-bent 3/4" PVC electrical conduit protects the line through the wall and dirt.
    Weil-McLain Gold P-WTGO-4 DOM 07/09/96, rated 1.25 GPH
    Beckett AFG Burner DOM 05/23/96, F4 Head
    Delavan 1.0gph 80° B solid nozzle
    10 Micron Westwood spin-on
  • STEVEusaPASTEVEusaPA Member Posts: 3,481
    I think you need to re read my posts.

    They make an angled tank valve with a flare-less fittings/less leaks. No filter outside, 3/8" all the way of coated copper. The coated copper is enough to protect thru the wall, seal with caulk both sides, expansion loops at tank and burner.

    All flare fittings...
    -Angled tank valve, expansion loop
    Enter building...
    -Firomatic, both filters, cartridge then spin on. Usually the spin on comes with a bracket you can mount to the wall, or you can make one. Just make it so you can get something under the filters when you change them.
    -OSV it proper place (still waiting on the sketch), then expansion loop, firomatic at the burner.
    For bleeding, I usually disconnect the flare after the osv. Depress the button and bleed into cup until you get oil. When you release button oil should stop. Which is a good way to check it every time you replace filters.
    Then reconnect, go to the burner, fire it up and power bleed it properly.
  • BinDerSmokDatBinDerSmokDat Member Posts: 23
    First, thanks to everyone for being so patient and taking the time to explain things.

    SteveusaPA, I was taking a little bit of what everyone said and putting it together. Your suggestions of expansion loop, inside inline firomatic and OSV + going with 1/2" line. I missed the part about a cartridge AND a spin-on (more on filters below).

    I agree that an angled valve off the tank is the way to go. In my original post that's what I meant about a lack of fittings in 1/2". I can't seem to find a one piece 1/2" MIP to 1/2" flare angle valve. If I can get all 1/2" flare fittings, I see no harm in going from the tank to the filters with 1/2". As others have commented, if gels or crud show up 1/2" is better than 3/8" right? Also wouldn't that help flow, at least up to the 3/8" fittings on filters?

    As for filter options, I know there are as many opinions as their are guys qualified to do this work. (And more from guys who aren't. ;) ) For now I'll leave the filter discussion out of this (other than OSV pre- or post- filter) and stick to the fuel line.

    I got a chance this morning to do a diagram.

    Weil-McLain Gold P-WTGO-4 DOM 07/09/96, rated 1.25 GPH
    Beckett AFG Burner DOM 05/23/96, F4 Head
    Delavan 1.0gph 80° B solid nozzle
    10 Micron Westwood spin-on
  • STEVEusaPASTEVEusaPA Member Posts: 3,481
    Last time, then we have to explore your name, specifically the 'SmokDat' part.

    Based on your drawing...
    All flare fittings
    -Regular tank valve outside, not firomatic, then expansion loop.
    -3/8" jacketed oil line all the way.
    -Firomatic where the number "36" is in your drawing, then filters.
    -After filters, thru the 2x4 wall, no stem valve (against code).
    -At a max height above floor of 3', an oil safety valve.
    -For easy of maintenance (swinging the boiler door), I'd put a firomatic mounted at the right side of the boiler, then the 24" flex into the bottom inlet port of the fuel pump.
    Here's an example of double filters and an oil line coming in from the outside, but you wont be putting the OSV in that location due to your 7' drop.

  • BinDerSmokDatBinDerSmokDat Member Posts: 23
    Thanks Steve, 3/8" all the way it is!
    In case it wasn't clear, that drawing is my current set-up.
    I knew the stem valve wasn't code, they want you to exercise the firomatic valve. I always thought it odd that I have NO firomatic inside the house, where a fire is actually most likely to occur. But I have one outdoors with a brick wall, concrete pad and asphalt driveway with no cars or flammable material within 20 feet.

    One last question, the block wall will be a finished wall shortly, stucco over block.
    I don't think filters hanging off my den wall will make She Who Must Be Obeyed happy.
    Can the filters be mounted between the 2x4 wall and boiler, say in the location the stem valve is now? Then the OSV ≤ 3' up from boiler?

    As for my name, I'm a cigar smoker but I've cut back.
    I now only smoke cigars on days ending in "y."
    Previously I'd smoke on days ending in any old letter. ;)
    Weil-McLain Gold P-WTGO-4 DOM 07/09/96, rated 1.25 GPH
    Beckett AFG Burner DOM 05/23/96, F4 Head
    Delavan 1.0gph 80° B solid nozzle
    10 Micron Westwood spin-on
  • STEVEusaPASTEVEusaPA Member Posts: 3,481
    edited September 11
    The filters are better closer to the tank. But they can be anywhere that makes everyone happy. You wouldn't want them in a finished room.
    I'd still put the firomatic where it enters the house even if it means a small access panel or above a drop ceiling.
    I personally hate the firomatic valve, specifically because it's a PIA when (not if) you have to replace them.
    I'd bet the person who put them in the code has a relative who makes the valves.
    I've never seen or heard of a story (I'm sure they're are a few) where the firomatic 'saved the day' in a house fire.
    But better safe and annoyed than sorry and sued (for me).
  • BinDerSmokDatBinDerSmokDat Member Posts: 23
    I can put an access panel and hide the firomatic with a little creativity. The filters would be harder to hide.

    I've never even tried to turn my outdoor firomatic. The line was replaced between the tank and stem valve because of corrosion on the outside by the company providing service and oil at the time. The tech who came to do it said he hates that part of the job, if the firomatic won't turn or breaks or won't open again after it's closed, there is nothing to do but drain the entire tank and replace the valve. Thankfully it turned fine.

    I'm not concerned with the firomatic now, because I'm going to run the tank down to almost empty, siphon off any remaining fuel through a canister filter rigged to a fuel transfer pump then put it in a drum. It will serve as fuel for the multi-fuel garage salamander which runs on #2/diesel/kerosene. I want a clean start.

    I'll switch to the all new tank, line and filters. At most the boiler will be offline for 30-60 minutes while I switch the tanks and then add 30 gallons of fresh diesel to the tank to cover me until the first fill-up.
    Weil-McLain Gold P-WTGO-4 DOM 07/09/96, rated 1.25 GPH
    Beckett AFG Burner DOM 05/23/96, F4 Head
    Delavan 1.0gph 80° B solid nozzle
    10 Micron Westwood spin-on
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