replacing head seal

[seatotaler]

I'm replacing the seal on my Mansfield head. Model no. 806, serial no. 4110170 mfg. date 11/6/84. So I gave that information to the salesperson at the marine supply store and they sold me a Dometic seal kit mfg. no. 385311462. These guys know their stuff and I've been dealing with the sales guy there for at least 25 years. So I had no reason to doubt him. Once I removed the head I realized my seal is different. It has a overflow drain hole as well as a lip on the inside opening. I don't see the function of the lip though. It doesn't fit into anything on the base assembly.

However my lower half (base) has the hole sealed off. It looks a bit like compressed wax seal material at first, but I think it's actually epoxy and it's hard as a rock. My thumbnail won't even scratch it. It doesn't even look like it was an after thought because the outer edge is perfectly round. Meaning it looks like it was done at the factory maybe. The top half of the head does have the hole for the overflow however.

The new seal has a slot for the locater pin but it doesn't have a lip on it. Same shape both sides. The inside diameter of both seals are the same if you don't consider that lip. The kit also has another seal that appears to be silicone maybe, and is about the thickness of a credit card and the directions show it going on below the rubber seal. The inside diameter of the silicone like seal matches the inside diameter of that lip on my old seal. My head only has the rubber seal.

So my question is since I don't have an overflow hole will this new kit work for my head? It sure looks like it will do the same job, but since the kit was about $50, I just want to check first, since it won't be returnable once I try it. The outside diameters are the same and so is the thickness of the rubber seals.

https://tawkyn2u.wixsite.com/topseaturvy/blank

[peghall]

Which Mansfield toilet are we talking about--the VacuFlush or one of the manual toilets (751 or 752) that SeaLand Technology discontinued shortly after buying the marine division of Mansfield Plumbing?


--Peggie

[seatotaler]

Originally Posted by peghall

Which Mansfield toilet are we talking about--the VacuFlush or one of the manual toilets (751 or 752) that SeaLand Technology discontinued shortly after buying the marine division of Mansfield Plumbing?


--Peggie

VacuFlush

[peghall]

To give you a little history...Mansfield introduced the VF in 1978...they spun off their entire marine division to SeaLand Technology in 1984, which would make yours one of the last ones made that carries the Mansfield name. SeaLand was sold to Dometic about 10 years ago.

With any equipment that's 37 years old, it's impossible to know how much is still original or even when vaious parts were replaced unless all the owners during those 37 years kept meticulous records, which is unlikely. Most of the parts have been redesigned at least once in the last 30 years. Only VacuFlush parts will fit a VF.

So you need to call Dometic 800-321-9886. They're almost certain to hand you off to the "authorized service center" nearest to you, 'cuz ..the best your guy at your favorite marine store can do is check the book for the seal designed for the current bowl assembly. There's no guarantee the service center will have the one you need, but they'll have records of the older ones and the knowledge to know whether you can still get what you need.

If you can't...all equipment has a lifespan...it may be time to give your geriatric VF a decent burial and shop for a new toilet. Marine toilet technology has evolved considerably since 1984...there are now several toilets that are better, simpler and less expensive while offering everything the VF does and more. And I'll be glad to help you find the best fit for your use, your boat and your budget.

--Peggie

[seatotaler]

Thanks for the info. But after looking at my pictures do you see any reason why the new kit wouldn't work? Given the fact that the overflow hole isn't being used anyway? Plus the new rubber gasket and the other silicone gasket fits perfectly.

[peghall]

I'm concerned that the notch for the "overflow" (which I've never seen on a VF seal before) will prevent it from sealing completely...that it'll leak. That may explain the reason for the "gunk" on the old one. Without some advice from a VF tech, there's no way to find out without installing it. So I still think you should talk with a Dometic VF tech before you do.



--Peggie

[seatotaler]

Originally Posted by peghall

I'm concerned that the notch for the "overflow" (which I've never seen on a VF seal before) will prevent it from sealing completely...that it'll leak. That may explain the reason for the "gunk" on the old one. Without some advice from a VF tech, there's no way to find out without installing it. So I still think you should talk with a Dometic VF tech before you do.



--Peggie

Sorry, but I'm not following your thoughts. I would think if anything, the fact that the overflow hole is sealed, and the new gaskets don't even have holes in them for an overflow, that it would make an even better seal.
You mentioned the "notch". My thoughts are that notch is there to just insure that the old gasket was installed the correct way to make sure the hole in it lines up with the overflow hole.
The fact that the new gasket has that notch, and no hole for the overflow, leads me to think that it is an updated seal for VF toilets that have that overflow hole sealed over. Or at least to include my type with newer styles. It's just a theory. It's worked for me for many years and the person I bought it from owned the boat for decades and he did keep excellent records, ( being a commercial pilot) No mention in his log about issues with his VF system.

[seatotaler]

Perhaps I should explain what my problem is. I just thought that maybe by starting at the top so to say, I might find the problem without tearing the system apart. The seal seamed simple enough, until now. I thought it was going to be a slam dunk. If it stopped the problem, great. If not I'd explore more. Not having done any marine plumbing before, It appears to me that the seal is only basically to join the toilet to the base without any leaks of water. There was no water leaking onto the floor, so now that I have it apart, I'm thinking I was looking in the wrong place to solve my issue.

I have what seems to be called a S series system. So I have a vacuum accumulator tank that looks like a small scuba tank. I have 12 volt pump ( black body). The system still works ( doing it's job) However the pump runs continuously. I've just got into the habit of using the breaker switch to operate it when needed. Once I hold down the lever to fill the bowl with about a couple inches of water, it slowly leaks past the half round ball. That process takes about maybe 30 minutes.

It doesn't make sense to reinstall the old seal since it has slight compression recesses the shape of the porcelain on the top side of the seal. So once I put it back together, with the new seal and turn on the breaker, I fully expect the pump to run continuously.

If you have a car tire with a slow leak the trick is to take a plant mister with soapy water and spray around the rim and you'll probably see bubbles indicating a rim leak. With that is mind is there a similar type of test I can do to narrow down my source of problem?

I just discovered something that may or may not mean anything. On the back of the top section hidden from view is what's called a vacuum breaker. The parts list and picture I found online of the 806, shows one chamber. Mine has 3 ( if that means anything) Anyways there is a pvc connection going through the porcelain ( like a thru hull) with a rubber gasket. The large pvc nut has hand tight. I tightened it by hand about an 1/8th of a turn. ( just to give you an idea of how loose it was, I'll tighten it slightly more with a wrench) I'm just wondering if that might shed any light to my issue? Or am I dreaming that it could be so simple a fix.

I've just added picture of what I'm talking about. There was a sponge like material sitting on the top of the vacuum breaker that has completely decomposed into almost a powder. Was that working as an air filter? Perhaps I need to take that vacuum breaker off and clean it out.

I've just added two new pictures to show what I'm talking about.

[seatotaler]

Also I forgot to mention that inside the toilet bowl at the back is a factory like plug. I'm assuming it is blocking off the overflow hole in the bowl, which seems to go hand in hand with the hole being plugged in the lower portion.
I've added a picture to show the plug

[peghall]

I didn't see any photos...


I have what seems to be called a S series system. So I have a vacuum accumulator tank that looks like a small scuba tank. I have 12 volt pump ( black body). The system still works ( doing it's job) However the pump runs continuously.

The 12v pump is--or should be--the S-Pump (vacuum pump). It runs continuously because the vacuum tank switch is worn out. That switch is at one end of the vacuum accumulator tank, has a cap over it that's easy to remove, and it has a sensor in it that turns the pump off when it's achieved sufficient vacuum, turns it on when vacuum drops due to flushing or an air leak. It has an average lifespan of 2-5 years. It's easy to replace: disconnect the wires to it--making sure to note which wire goes to which terminal--and unscrew it from the tank. Thread a new one in and reconnect the wires...you're done.

Once I hold down the lever to fill the bowl with about a couple inches of water, it slowly leaks past the half round ball. That process takes about maybe 30 minutes.

Sounds like you also need to replace what used to be called the "ball, shaft and cartridge" kit. If you've been easing the pedal up after flushing instead of just letting it go to spring back into place with enough force to seal it, it's gradually developed a memory that no longer will do that.

As for the vacuum breaker...that's a part in the fresh water supply line that prevents backflow or a siphon from forming in it. The other part on the back of the bowl is the water valve...it's the "faucet" that lets pressurized water into the bowl when the pedal is depressed or lifted, blocks it when the pedal is let go.

If you'll send me a PM that includes your email address (no way to attach anything to a PM), I can send you some diagrams, schematics, the VF trouble shooting guide (the VF has changed so little except cosmetically that the same trouble-shooting guide works for all models, all years) and my article "VacuFlush 101" which explains how it works (you prob'ly know, but a "refresher" still may be useful) and how much water it really needs to keep it working trouble free. (This offer is open to anyone who wants it).

--Peggie

[seatotaler]

Thanks for the info about that switch being an easy replacement. However I can't even reach that end of the tank. If I remove the two monster pipe clamps holding it in position and remove the aft end hose, ( can't reach the forward hose clamp) I might be able to spin the tank around counterclockwise slightly to get at that switch, but that forward hose is pretty stiff. The switch is at least 3 feet forward of the floor access opening. The other option might be to lift up the glued down carpet in the forward stateroom and drill a 6 in. hole in the floor right above that end of the tank.

If you go back to my original post there is a link to where the pictures are.

[seatotaler]

As for my procedure in flushing the toilet. I'm just following the instructions that are on a Mansfield sticker on the wall. It reads
For solid flush- lift flush pedal to add 2 inches of water
To flush head- Press pedal and hold approximately 3 seconds
btw, thanks for trying to help

[seatotaler]

I'm about to replace the vacuum switch on the vacuum tank. From a bit of You Tube research I believe I'm looking for a Dometic vacuum switch p/n 385318032. I'm having a ton of problem unscrewing the switch from the tank. Are there any tricks of the trade? I've tried a large oil filter clamp but it's not big enough. I believe mine switch is about 4 1/4" dia. at the thin lip against the tank. Mine is at an almost impossible place to access it. I had to drill a hole in the floor under a set of drawers. But I can't put my hand on the switch and see it at the same time. The switch end of the tank is pointing towards the bow and the tank is about 2 feet forward of the bilge access hole. I can sort of reach the switch that way too. However, I can only barely get my hand on it this way as well, while my head is still above the floor. I did manage to put a 1/2" open end wrench on one of the 4 plastic posts that protrude on that switch. But as I try to rotate the switch that way, I think I might have got it to budge, however I get the sense that that plastic post will snap off. grrrrr!!
Another question is will I be able to have my water on while the switch is out? I'm going to buy a new one first before removing the old one. However I'm a liveaboard so if something goes wrong, I don't want to be without water for an extended period of time.

I have the head breaker shut off. I have the water shut off at the ball valve going to the head. I have opened the flush ball valve in the head. I'll also shut off the water breaker. Once I remove that switch, will I be able to turn the water breaker back on with the end of the vacuum tank open?

[peghall]

You should definitely buy everything you need to replace before you remove anything!

It's always a good idea to turn the power to the toilet off before doing any electrical work, but it shouldn't be necessary to turn the water off to replace the vacuum tank switch. However, you may need to turn it off before swapping out the ball and shaft kit.

I did manage to put a 1/2" open end wrench on one of the 4 plastic posts that protrude on that switch. But as I try to rotate the switch that way, I think I might have got it to budge, however I get the sense that that plastic post will snap off.

The ONLY thing you should put a wrench, pliars on or otherwise try to unscrew the switch assembly is the edge of the cap...the posts are electrical connections --where the wires you have to remove (and hopefuly make note of which wire goes on which post before removing anything) go. Damage anything ON that cap and you'll have wasted at least $175. If that cap doesn't want to be unscrewed, maybe someone else reading this thread can recommend a product to loosen the threads.

I think you should try to recruit some help from someone who can get it out and screw in the new one. 'Cuz all of us have more and more difficulty contorting our bodies into tight places as we age. I'm even finding that it's a good idea to know exactly how I'm gonna get up before sitting down on the floor! I'd bet one of your dockmates has a teenage son who can help you out.

--Peggie

[seatotaler]

The ONLY thing you should put a wrench, pliars on or otherwise try to unscrew the switch assembly is the edge of the cap...the posts are electrical connections --where the wires you have to remove (and hopefuly make note of which wire goes on which post before removing anything) go. Damage anything ON that cap and you'll have wasted at least $175. If that cap doesn't want to be unscrewed, maybe someone else reading this thread can recommend a product to loosen the threads.

It sounds like we're not on the same page here it seems. I'm talking about the white plastic block like sections rising up from that lip area that meets the tank when screwed in. They measure about 1/2" by about 3/4" and about 3/4" deep. The pictures I see on line of the 385 318 032 switch have two of them across from each other. Mine has 4, so it would seem that they had been updated since 1984, which is the date on my actual switch on the end of it. There is no electrical connections or source of electricity near these post like protrusions. It is my understanding from You Tube, that the screw that holds the end cap on, is screwed into the side of it, as was the case with mine. Plus it sounds like I have to predrill the hole in the new switch for that end cap screw. I also think they are used to grip the assembly as you thread it in to get it as tight as possible.
I'm not at all sure what you are referring to about the cap and wasting $175 ? The cap that covers my switch is simply thin plastic/pvc. If for some reason it got broken, a tall yogurt container and some silicone would do exactly the same thing. Simply cut a hole in the side of it for the wires to run through and seal it with silicone to protect it the switch from moisture. Obviously that is a red neck fix. I just mention that to emphasize the simplicity of the cover. In reality a 4" dia x 5" long piece of thin wall PVC and a PVC cap glued on to the end would be perfect if needed. Total investment would be less than $10. So I'm confused about the $175 amount? The switch is around $300.

I think you should try to recruit some help from someone who can get it out and screw in the new one. 'Cuz all of us have more and more difficulty contorting our bodies into tight places as we age. I'm even finding that it's a good idea to know exactly how I'm gonna get up before sitting down on the floor! I'd bet one of your dockmates has a teenage son who can help you out.

I guess I haven't explained the location of the Vacuum tank properly. If you had a one year old child, you could in theory lower them into that portion of the bilge through the access opening in the floor. But then how would you explain to them what they had to do? But a two year old child would no doubt be too big to fit.
I have about 2 and a half feet from my armpit to my finger tips so maybe 6 more inches of reach might be of some advantage I suppose. There is too much plumbing in the way right below the access opening (16" x 16"), and that plumbing is sitting on top of the fresh water holding tank, which is only 6 inches below the opening. You can either put your arm in to touch the end of the switch or lower your head in and catch a glimpse of the switch off to one side and forward a couple feet.
My feeling is that that vacuum tank was fitted in place before the floor and fresh water tank was installed. If that tank ever needed to be replace the only way to get it out would be to cut out the floor in the hallway, extending that 16x16 opening an extra foot or so in the forward direction. I'm contemplating doing that just to get the new switch installed, but I'll try doing it through the small hole I cut in the floor under the drawers first.
Once again because of wall partitions the hole is small so I can only look at the switch, or touch it, but not both at the same time. The hole is 6" x 4 1/2". can't go any bigger. I've estimated the dia. of the switch being 4 1/4" so even going through that hole might be fun. It's pretty much a guaranty that I'll drop the screws multiply times into the bilge before I get the switch wired up. Getting the wires off was very similar to reading brail, trying to line up the end of the slot screwdriver with the head of the screw with the end of my fingers and trying to position the screwdriver so it was in line was a guessing game that took about 10 minutes for each of the two screw just to get them out. All the time lying on my stomach, with one arm in the drawer opening which is about 6" high and then through that small hole in the floor and them the switch is about a foot down. Those electrical contact screws will be replaced by robertsons hopefully, or at the very least phillips. Why hasn't somebody outlawed slot screw by now. !!