Lavac toilet woes

[drlizard]

Greetings- I've had a Blake's Lavac toilet on my boat(s) for over 25 years. Great simple design, lots of versatility in plumbing options, very serviceable....until lately. I had to rebuild the Henderson pump every 6-7 years or so, not bad for full time cruising/living aboard. Lately, the pump started failing after rebuild in 2-4 months. 3 times in less than a year. The rubber swells up and distorts. I've always used vinegar as the only toilet bowl cleaner, and with great success until now. Now if I use any vinegar the pump innards go bad quickly. I suspect the rebuild kit material has changed, and is nitrile or neoprene, but it is not apparent from packaging. Which material is unharmed by vinegar? How does one tell nitrile vs neoprene, and is that the issue? Anyone else tired of buying and rebuilding?

[peghall]

It's quite possible that the rubber material used in the pump has changed recently...so many equipment mfrs are now using components and materials sourced from China because they're so much cheaper than the better quality materials they previously used. Any soft rubber that's left to soak in vinegar will swell and distort...it's also a problem that affects joker valves in other marine toilets as result of allowing vinegar to sit in the bowl. I suggest that from now on you follow any vinegar bowl cleaning with a fresh water rinse.



--Peggie

[hpeer]

I would call the mfg directly and ask.
I have had mixed results asking similar questions of them re: fuel transfer.

One would think their bilge pumps would be nitrile but who knows.

So company ownership has changed over the years, but not recent info.

Maybe there are different part numbers you need to specify.

I would be glad to hear your report as I have Lavacs also.

[wrwakefield]

I also have had Lavac heads with Henderson Mark V pumps on my current- and a couple of past boats- so I follow with interest.

I’m relieved to read the issues you are having are not with the Lavac Head itself, but with the [much cheaper!] Whale Mark V pump.

For comparison, I finally had to rebuild one of our Henderson [now Whale] pumps last year after 10+ years of full time use. I bough a new rebuild kit online, so it is [may be?] fairly recent.

We don’t happen to use vinegar in the heads, but do use two other potions:

-CLR [contains lactic and gluconic acids] for removing hard deposits. [Typically 1-2 hour treatment periods w/ 1pt CLR added to a freshwater flush.]

-CP enzyme for removing organic matter. [Typically a 24-48 hr treatment period.]

Side note: Both of the above are used in our shower drains also- which are evacuated using Whale IC diaphragm pumps- likely with the same elastomeric components…?

We haven’t [yet…] had any issues with shorter lifespans of the rubber [nitrile?] components on any of these Whale pumps [4 total.]

Are the elastomer components nitrile, neoprene, EDPM, or ??

In a quick search online, I only found one online reference [reseller] that claims nitrile is used in the Mark V pumps.

I also noted that Whale offers the option of nitrile or neoprene in the rebuild kits for the larger pumps. [e.g., Gusher 10, etc.]

Whale [now a Navico company] seems mute on the topic for the Mark V we are discussing:

[From the Whale installation manual- where it would appear the lawyers took over the technical writing from the engineers…]

Application:
This pump is designed to pump water.
Output capacity depends on installation conditions and pumping rate. Users should be aware that capacity may not be sufficient to cope with rapid influx of water.
If it is intended for use for any other purpose or with any other liquid, it is the users' responsibility to ensure that the pump is suitable for the intended use and, in particular, that the materials are fully compatible with the liquids to be used. With all applications, it is important that a system of safe working practice is applied to installation, use and maintenance.

Lets assume nitrile [most likely for oil resistant bilge pumps] or neoprene, and look at a chemical resistance chart for various rubber compounds.

Gleaned from the above linked chart:

LEGEND: 1 = Satisfactory, 2 = Fair, 3 = Doubtful, 4 = Unsatisfactory, X = Insufficient Data

Vinegar:
Acetic Acid, 5%: Nitrile 2; Neoprene and EDPM 1

CLR:
Lactic Acid, Cold: Nitrile 1; Neoprene and EDPM 1
Gluconic Acid: Nitrile 3; Neoprene and EDPM 1

I have a hard time drawing any firm conclusions from the above exercise, but will hypothesize:

Based only upon your experience with vinegar degrading the [recently acquired] pump rubber components prematurely, one might conclude that neoprene or EDPM was used in the past, but switched to nitrile at some point recently [last year or so?]

My experience using a dilute CLR solution might also support that conclusion. But only Whale knows, and I haven’t found anything to indicate they are sharing that info…

I look forward to hearing Whale’s reply to your inquiry.

Cheers, Bill