Cummins Marine Diesel Repower Specialists Forums General Discussion Testing a generator siphon Break

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  • #58465

    Joe Monaco
    Participant
    Vessel Name: Tunacious
    Engines: 3126 TA 420 hp
    Location: San Diego
    Country: USA

    Saw a sticker saying I need to test the syphin every 6 months. How do I do this and do people really check their syphins every 6 month? How do they stop working?

Viewing 9 replies - 1 through 9 (of 9 total)
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  • #61200

    Joe Monaco
    Participant
    Vessel Name: Tunacious
    Engines: 3126 TA 420 hp
    Location: San Diego
    Country: USA

    Thanks Rob! I put a copy in my boat file.

    #60792

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    Vetus Air Vent

    That’s a Vetus Air Vent unit. Here’s the manual

    #60773

    Joe Monaco
    Participant
    Vessel Name: Tunacious
    Engines: 3126 TA 420 hp
    Location: San Diego
    Country: USA

    Here’s a photo of my set up. I didn’t notice before it has a hose coming off it. Looks a bit different from the setup shown in the artical.

    #59115

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    I have seen “pissers” on sailboat engines… and of course on mains too.

    #59030

    Justin Riege
    Moderator

    Anti Siphon.. That Makes more sense.

    Pics always help…

    Did you see number 8 in the article you posted… A fail safe anti siphon diversion hose.

    “8. If a valve fails, the consequences could be dire. I and other people have sometimes removed the valve from the loop in the engine system (NOT the head discharge) and installed a hose from the air vent in the loop to a vent overboard[/u] where a small amount of diverted water flow can be easily seen when the engine is running. With this arrangement, you don’t worry about the valve hanging up. The vented passage is always open. And you can easily tell when the water is running and when it stops. This flow, however, must not be of such volume that it adversely affects the cooling of the exhaust.”

    For a generator this would probably need to be a pretty small hose so you don’t bypass too much water.

    Thoughts on these on a generator…Rob???

    #58922

    Joe Monaco
    Participant
    Vessel Name: Tunacious
    Engines: 3126 TA 420 hp
    Location: San Diego
    Country: USA

    Thanks Rob,

    I’m out of town so I can’t check but I think your right. I did some googling and found this.

    https://www.boatus.com/magazine/2018/april/anti-siphon-valves.asp.

    I need to look at my set up more closely. I don’t remember seeing any valve on top. That’s what had me baffled, didn’t see anything to check, but it must be there and yes the artical says that salt/crud can build up and render the valve “break” inop and if that happens you could flood your generator with salt water after it stops running.

    I noticed the Red warning sticker by the plastic U high on the bulkhead the other day and didn’t have time to look into it but now it appears it’s a pretty big deal if it stops working.

    Anyone ever seen this happen? I never heard if this? I guess Im the only one that wasn’t checking his generators syphon valve every six months! I’ve owned the boat 4 years and I’d bet money it hasn’t been checked in 10+ If ever…

    Now I’m wondering are there other random or unusual checks I’m missing…

    #58867

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    It’s after the raw water pump, correct? There should be a small valve at the top of the siphon break that closes under pressure and then opens when pressure is lost (engine shutdown). There should be a removeable cap at the top of it so you can check and clean it, no? How about some pictures.

    #58842

    Joe Monaco
    Participant
    Vessel Name: Tunacious
    Engines: 3126 TA 420 hp
    Location: San Diego
    Country: USA

    It’s not the sea strainer. It’s a plastic upside down U in the raw water circuit. I think it is an anti syphin device to prevent water from running into the engine with it off. The sticker says test every 6 months. I’ve never tested it and I’m not sure how? Maybe take the hose off the generator side and see if water comes out? Every 6 months? Asspain…does anyone do this. It’s just a hollow tube how would it ever stop “working”?

    #58743

    Justin Riege
    Moderator

    Siphon

    I am assuming you are talking about the raw water circuit from the thru hull, thru the sea strainer to the raw water pump.

    I would be monitoring that at all times in one way or another. First by making sure you have water flowing which is critical to any engine.

    As long as water is flowing you are “probably” good on the Siphon. It is possible to have an air leak, loose sea strainer lid, loose fitting, in which case air could get sucked into the system. I would take a peak at my sea strainers a lot more often than once every 6 months. Raw water flow is something you should be monitoring at all times.

    Take a peak at the strainers before every run. If the sea strainers are full with water and the engine has plenty of raw water flowing, good engine temps etc, then you are good to go. If the strainers have a lot of air in them, you might have a leak on the suction side essentially breaking your siphon.

Viewing 9 replies - 1 through 9 (of 9 total)

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