Lavac Conundrum

[Pioneer18260]

Our Lavac Popular has served us very well for its several years since new installation, & any difficulties have been easily/eventually resolved. We've recently replaced the Mk.V rubber parts kit as well as the toilet seat & lid seals, all as preventive maintenance. The system is kept very clean with lots of flushes & nothing but human waste deposted. The only ongoing annoyance has been sometimes-stiffness in the pump operation, which seems to be remedied with our treatments of vinegar, cooking oil, & about once a year some careful muriatic acid flushing, all recently done. Our intake thru-hulls must be clear because we bring in water well. Our outlet must be open because we do get flow through, although we haven't visually inspected the two thru-hulls for several months. We are not in growth-prone water. We can pump overboard or into our holding tank.

Here's our recent problem: After a few strokes every few flushes, the pump stiffens up & is very hard to move the handle. With waiting, some persistent part-strokes, gentle mini-strokes, we eventually coax the flow to move - but, completely different from all the years of normal operation, we hear a rumbling, bubbling sound for a minute, maybe more, of air moving through the water in the outlet line & out the thru-hull.

We think all our connections are tight & parts installed properly - but large amounts of air seem to be getting into the system & locking up the pump.

Any precedents? Hope you can help. Thanks so much.

Ron & Judy
Pioneer, CR38

 

[Peggie Hall HeadMistress]

Sounds like there's a blockage somewhere

Most likely sea water mineral buildup in the head discharge line or y-valve, or a partial blockage in the tank vent. It's creating backpressure that makes the pump increasingly hard to pump. You're adding large amounts of air by pumping...it's the air that's creating the backpressure. The rumbling bubbling sound is the sound of that pressure escaping.

Since you're not having any problem bringing in flush water, only discharge, we know the problem isn't in the intak line or thru-hull. You say the discharge thru-hull "must be open because we do get flow through"...but actually, you're NOT getting flow through, you're experiencing a considerable amount of backpressure. So that's the first thing I'd check.

If you've cleaned out the system with muriatic acid, it may be that you didn't use a strong enough concentration or leave the solution in the line long enough to dissolve all the buildup...or you may have a kinked hose...or a problem in the y-valve...a guest flushed something they shouldn't have...you're just gonna have to run it down and find it.

 

[Pioneer18260]

Re: Sounds like there's a blockage somewhere

Peggy,
Thanks so much. We're working on it. We needed an expert take on the situation; you've confirmed some of our suspicions & provided more to go on.
Ron & Judy
www.totallyfloats.com