Water tank vents

[mesteve]

On our 43DS, we have 2 tanks that total 153 gallons, that based on the water pump running constantly, we figured had been emptied.  So we filled them.

The problem is, the water pump was still running…. After a few trial and error attempts at chasing down what might be going on, I opened a deck fill back up, to be welcomed by a woosh of air going into the tank…. So the water pump was creating a vacuum in the tank, hence no water.  My initial assumption is water in a low point of the vent line.  Que the next problem; we don’t have any overboard vents like I’ve seen on other makes.

Where should I look (without starting at the tank and chasing upwards) to find a tank vent on a Jeanneau?

[nieamm]

On my j57 the tank vents are located on the topsides directly `outside` of the filling caps. When filling you should be able to hear a wuushing sound in them even with the air escaping through the filling cap also.

[Don Reaves]

On my SO35, the aft tank has a vent through the topsides near the tank. The forward tank vents in the anchor locker.

[mesteve]

Ah! There are 2 vents in the anchor locker!  Hadn’t chased down what those were yet…

That seems as good a place to start as anywhere.

[wheelsucker]

Unless you have a very unusual 43DS, you have should have 3 tanks for your 153 gallons (one under the V-berth, one on the starboard side under the settee, and one in the bilge just forward of the diesel tank).

If the fresh water pump is still running after you filled the tanks (all 3), you may need to bleed air out of the lines by turning on the faucets in both heads and the galley at the same time (and maybe the wash down hose in the stern).  I only have two tanks (prior owner replaced the V-berth tank with a 2nd diesel tank) and only need to turn on the the head & galley faucets to bleed the lines.

Note that I've found that the fresh water pump sounds different when pumping air (quieter, higher frequency) vs. water (louder, lower frequency).  The faucets will spurt as the air is bled out.

Let us know how it goes.

[mesteve]

Under the nav station, we have a set of valves labeled starboard, bilge, and accumulator, in the factory gray lines; no indication of a forward tank there. Also haven’t seen a 3rd deck fill, but to be fair, we have a dingy and jerry cans covering most of the foredeck.

And unfortunately our v berth is stil covered with the remnants of moving aboard…

[wheelsucker]

This is from a local 43DS charter boat guide that we used before we bought our 43DS.  In our boat, the top (bow tank) valve has a big "X" through it since it is now a diesel tank.  Which tank is currently being used on your boat?

[mesteve]

Same “manifold” very different labels…

All 3 are open at the moment

[wheelsucker]

That could be part of your problem - I've only seen (and heard) of one valve being open at a time; the other two are shut.  Usually that is to make sure that your water consumption meter is accurate per tank, but if you have an empty tank (bow?) and they are all open, I'm not sure the if the fresh water pump can overcome all the air in lines.  Normally I'd say shut off the top valve and one of the bottom two (so only one of your filled tanks is open), but having one labeled "accumulator" is unfamiliar to me.  Is the valve labeled "accumulator" in the equivalent position of the bow tank valve in the picture I sent?

By the by, look at page 38 of your owners manual to see the layout of the fresh water tanks, fill lines and vent lines.  Unless you have a custom 43DS somehow, the bow tank deck filler is on the port side forward (number 3 in the diagram).

[mesteve]

It is the middle valve labeled accumulator.  And, having a bow tank answers several questions, like the factory grey water line heading forward under the forward sink…. 

I would think you are correct that a forward empty tank would introduce the air experienced. Oddly filling the aft 2 tanks has remedied the sucking air problem, so I don’t know if the tank was back filled through the manifold to some degree or what.

[rxc]

You should not have all three valves open at the same time. Only one at a time. When the pump sucks air, open the valve for another tank and shut the valve for the one that is empty. Use the water meter to tell you how much water you have sucked out of each tank, so you know when you will need to refill the tanks.

You say that one of the valves is labeled "accumulator"? Can you post a photo of this?