Blackwater Diverter Valve Stuck

[Gone Gypsy]

Help!
The plastic diverter valve from black tank to either pump out or macerated discharge IS STUCK. Everything looks good clean dry. Had the boat three years and have never been able to open it. Tried tapping handle with small hammer. Worried might break it AND THEN find out you guys know an easy fix.

Any best practice?
Spray lube stem? Hammer more? Hair dryer?
Thanks, Gone

[GreenWave]

I would heat it up with a hair dryer or heat gun. Is it stuck open or closed? Or I guess holding tank or macerator

[Bowdrie]

What make of valve?
With some there is no "closed" position, the center port inlet either being open to one side or the other, (the rotating barrel having cojoined holes at 90 degrees).
They usually come apart with a few screws holding a cover plate with an O-ring seal.
If you do remove the cover plate the barrel comes out so you can clean the barrel and housing.
Re-assemble, liberally coating the barrel and O-ring with "water faucet grease" available at most any hardware store.

[jamhass]

Sounds like you really just need to bite the bullet and replace the valve, best also the attached hoses. Since it has be inop for 3 years, chances anything you might try will have a very good chance of breaking the valve, likely in worse shape than it is now.

Since the mess is currently contained, take a good hard look at the install, figure out what you need and what you can do to contain messes as you open it all up. Get it all ready and have a go at it. You will be time, hassle and money ahead.

[Gone Gypsy]

The valve is stuck in position allowing pump out dockside. Want to rotate for discharge thru hull to ocean. THE MESS of replacing or breaking it is what I was hoping to avoid! And I don’t need a major project right now. Will try some heat and maybe loosening but not removing the cover screws. Thanks. Will update once I get gloves off!

[Wayne Gilham]

Another method - good also for Forespar's Marelon (plastic) thru-hull valves, - is to wrap valve in rags soaked in the hottest water you can tolerate handling. Concept is that such localized wet heat (more quickly penetrating than hot-air of a heat-gun) will ideally expand the housing before the ball starts to expand - thus giving a pinch more clearance inside the valve

[Wayne Gilham]

Another "trick" to free a stuck plastic valve (recommended by Forespar for their Marelon thru-hull valves) is to wrap valve in rags soaked in the hottest water you can tolerate handling. Concept is that such "wet" heat quickly transfers heat and penetrates the outer shell to expand it possibly more quickly (and safely!) than heat-gun's hot air. Trick is to move the handle before the inner ball of the valve ALSO starts to expand from the heat.

[Cheechako]

Plastic valve? Get rid of it and put in metal.
You can try a hair dryer to heat it up.

[Tsuru]

Last year I replaced all the sanitary lines in Aurora. I was able to flush the lines and system out well prior to starting so it wasn’t as much as a disgusting job as it was just hard. I won’t go into the details except to say that Aurora has no odors, even when closed up during warm weather.
I replaced both of the 3 way diverter valves but one of the things I noticed was they were both almost totally plugged with hard scale buildup (along with the hoses). Saltwater reacts with urine in a way that causes the minerals (probably calcium) to accumulate on the walls of the lines and gizmos.
I now dose regularly with vinegar and yearly with an acid treatment. It is very possible that you could acid treat your system to help the valves. That said if the valve handle won’t move it is probably too late. I'm not an expert and won’t recommend an acid treatment procedure but I believe there are some commercial treatments available.
Good luck,