Author Topic: Diesel tank vent plumbing  (Read 347 times)

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linback

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Metal Workbench With Hanging Board
« Reply #9 on: October 22, 2020, 07:09:09 AM »
The metal workbench has a tool hang plate with louvre hanging plate and square hanging hole and can hang any kind of tools. The small work table can be equipped with lighting racks, hangers, shelves, square hole hanging boards, louvre hanging boards, power sockets, electrical boxes, parts box hanging strips, etc. The metal top of worktable can be customized. The clients can choose stainless steel or cold-rolled steel, offering ample space for a multitude of operations and tool solutions. It is made of a solid steel frame with advanced technique and strict quality control during the manufacturing process. A pegboard with hooks is ideal for hanging small tools, easy to take on and off. the non-slip rubber feet add stability and do not scratch your floor. The colour is optional.

jt11791

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Re: Diesel tank vent plumbing
« Reply #8 on: October 08, 2020, 05:42:45 PM »
Well after additional exploration, I'm fairly sure I understand the plumbing of my fuel tanks.

Plumbed to fittings on the tank cover are the main engine draw, the generator draw, and the return lines:


Then, off to the side, are the lines for the deck fill and the vent.  As noted by Ripple, the vent line is larger that the draw and return lines:
S/V Renegade  H54-19

Ripple

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Re: Diesel tank vent plumbing
« Reply #7 on: October 08, 2020, 05:07:34 PM »
Are we sure, I have spoken on this topic in the past and am still confused.
Hylas 49' #32 Shamaya
  My last post was cropped to the first word for some reason but I think it may have something to do with the use of an apostrophe. As I was saying, the vent hose is required to be 9/16 inch ID which is significantly larger than the fuel hoses. If one hose to the inspection plate is larger than the others, maybe it is a vent hose. If not you will have to look elsewhere for the vent hose. JR

800lance

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Re: Diesel tank vent plumbing
« Reply #6 on: October 08, 2020, 04:07:27 PM »
Are we sure, I have spoken on this topic in the past and am still confused.
Hylas 49' #32 Shamaya

jt11791

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Re: Diesel tank vent plumbing
« Reply #5 on: October 05, 2020, 12:55:31 PM »
I had not considered that there might be other connections to the tanks.  I assumed that the three lines I can see are fuel draw, fuel return, and vent, but I did not consider that there are two fuel draws, one for the main engine and one for the generator.  So the lines that I see could be fuel draw, fuel draw, and return, with an unseen vent line somewhere else. 

That makes much more sense!  Thanks to all for helping me.  I knew what I was seeing could not be right......
S/V Renegade  H54-19

Knoxan

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Re: Diesel tank vent plumbing
« Reply #4 on: October 05, 2020, 11:11:36 AM »
I would agree that it makes no sense to have the vent connected to a dip tube. From memory on my H46 the vents are taken from the top of the tanks at a side alongwith the filling entry from the deck fitting.
The tops of my three tanks have the following:
A dip tube for supply to the engine/generator/heating manifold.
A non dip tube connection for fuel return from the returns manifold.
A dip stick.
A second dip tube which mearly supports the small bore nylon tube from the bottom of the tank for connection to the tank tender.
A filler cap for checking tank interior.

Andy
True Brew
H46#32

jammin

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Re: Diesel tank vent plumbing
« Reply #3 on: October 05, 2020, 12:29:13 AM »
Hmm. The supply and return lines should be attached to the dip tube pickups. The vent should be attached to the top fitting. There must be no obstruction in the vent line in order for the tank to fill easily (or at all).

Ripple

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Re: Diesel tank vent plumbing
« Reply #2 on: October 04, 2020, 09:36:57 PM »
If I recall correctly on our h46, two dip tubes - for the Yanmar and generator - and a return line for both are in the inspection cover. The vent Fitting is way over towards the hull. JR

jt11791

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Diesel tank vent plumbing
« Reply #1 on: October 04, 2020, 03:13:18 PM »
Recently I installed fuel level sensors in two of my diesel tanks and I noticed something about the tank plumbing that I don't understand. 

There are three hoses plumbed to each tank, fuel draw, fuel return, and a vent line.  The hoses attach to three fittings on the tank cover and two of these fittings have stainless dip-tubes on the inside of the tank that reach down to the bottom.  The fuel draw line obviously must have a dip-tube to draw fuel from the bottom of the tank, but I was surprised to find that the vent line was attached to the other dip-tube.  I checked my other fuel tanks and they are all plumbed this way.  This setup allows air to be drawn into the tank as diesel is drawn out, but air in the tank cannot escape because the end of the vent dip-tube is under the diesel fuel.

Is there some logic to plumbing the tanks this way?  I would have plumbed the vent line to the fitting without a dip-tube to allow the tank to breath freely in either direction.  How are your fuel tanks plumbed? 
S/V Renegade  H54-19

 

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