Struggling Shower Sump...

[po46camelot]

Hello All

I have run into a problem while plumbing in an automatic shower sump. The current shower sump is a dedicated compartment of the bilge, approximate volume 30 litres, but the pump was really struggling to empty the grey water quickly - it was taking 20 minutes to empty. The remnant water below the pumps ‘switch off’ point would quickly start to smell so we bought a Seaflo Shower Sump to combat the problem.

The sump empties through a 19mm or ¾” i.d. hose through an inline ‘Y’ adapter via a vented loop located above the waterline, to a through-hull about 1m below the waterline. The ‘Y’ adapter also receives bilge water from our backup automatic bilge pump (1000gpa). I have plumbed in the new sump pump (600gpa) and it does not push water through at all, though the autobilge still empties (but slowly).

I have pulled the discharge hose (downstream of the vented loop) off the seacock valve and activated the sump pump -and it seems to work fine, with water pouring out the end of the disconnected hose. I have looked inside the elbow leading into the seacock and it looks fine -no obvious obstructions and the hoses look fine. I have jumped over the side and used a plastic rod to clear any growth/debris out of the water-side of the line, but that makes little difference.

Does anyone have any idea what may be causing this? Any hints at how to fix or even diagnose this problem would be appreciated. We are not due for a haul-out for another few months and I think we may need a shower or two before then!

Cheers

Dan

[Island Time O25]

Did you check the vent breather valve? Most have little screen thingy which gets clogged or corroded thus impeding its function.

[Searles]

If the outlet is well under the w/l it may simply be head pressure ,⛵️⚓️

[gonesail]

did it ever work right or is it something new? usually bilge pumps ( and the line) exit above waterline.

[po46camelot]

Hi All and thanks for your input. After reading the post by Searles I recalled that the original sump pump was an 1100gpa and it worked fine (but definitely not at a rate of 1100gpa), and the backup autobilge is 1000gpa.... perhaps it is simply a question of the smaller pump not being abl to push through the head (up 2.5m to the vented loop -which is clear; thanks Matt!-, and down 1.5 m to the seacock which is 1m below the waterline)... looks like a new through hull above the W/L for the sump is the solution, so will have to wait for a calm day (not today, thanks to the 60kn gusts whipping through from exCyclone Dovi which is affecting these parts) or until we pull out next month...
cheers!