Is a macerator supposed to be full of salt water?

[SteveWolf]

PLEASE! Only answer if you have torn down a macerator yourself. Not looking for uninformed opinions or guessing.

My macerator quit. Might have been due to eighteen inches of standing salt water I had to drive in to get to my condo after Hurricane Dorian. My macerator is bolted underneath the RV and open to all that I drive through. Yeah, the light sheeting sort of covering it provides some protection.

If you live or visit often an island thirty miles out in the Atlantic you will drive in salt water. Those who look aghast and say, “I will never!” are met with a polite smile. Be sure we will remove that “Salt Life” sticker off your truck. You don’t qualify.

I tore it down and found the motor housing full to the brim with water. Twenty gallons of clean water, a toothbrush and a good going over with a Dremel and it is back to full service. There is not much to a macerator pump.

Here is my question: Has anyone _with_actual_experience_ Plasti Dipped their macerator to seal it against water? It appears that outside of the screw rod hole this thing can be sealed. The screw rod can be run through a long piece of silicon tubing. Sealed with something on the pump side and zip tied against the rod a foot or so out, that should eliminate water intrusion there.

It doesn’t get that hot in operation. That’s not going to be an issue.

What say you, greybeards???

Steve

[booster]

Originally Posted by SteveWolf

PLEASE! Only answer if you have torn down a macerator yourself. Not looking for uninformed opinions or guessing.

My macerator quit. Might have been due to eighteen inches of standing salt water I had to drive in to get to my condo after Hurricane Dorian. My macerator is bolted underneath the RV and open to all that I drive through. Yeah, the light sheeting sort of covering it provides some protection.

If you live or visit often an island thirty miles out in the Atlantic you will drive in salt water. Those who look aghast and say, “I will never!” are met with a polite smile. Be sure we will remove that “Salt Life” sticker off your truck. You don’t qualify.

I tore it down and found the motor housing full to the brim with water. Twenty gallons of clean water, a toothbrush and a good going over with a Dremel and it is back to full service. There is not much to a macerator pump.

Here is my question: Has anyone _with_actual_experience_ Plasti Dipped their macerator to seal it against water? It appears that outside of the screw rod hole this thing can be sealed. The screw rod can be run through a long piece of silicon tubing. Sealed with something on the pump side and zip tied against the rod a foot or so out, that should eliminate water intrusion there.

It doesn’t get that hot in operation. That’s not going to be an issue.

What say you, greybeards???

Steve

What model of van do you have.


Just looked your have recent Roadrtek 190 which will have an upside down macerator plus some other factors, but in water that deep it still would get wet to some degree anyway, to some degree.


The motor likely filled up through the non drive end bell cap, which would have been modified to allow the spring loaded manual free up rod. There is no effective seal on that area and it is directly into the motor housing. The cap on that bell over the shaft is solid and gasketed from the factory for just that reason.


The other big issue is that the pump is upside down, so any water that get into the intermediate gap chamber between the pump and motor wont drain as the weep hole is on top. It will however get water into it from the top. Once the chamber is full to the shaft line it will likely get by the motor seal over time. There are complete pictures of all this on this site with remedies such as clocking the motor to flip the pump and sealing the end cap and getting rid of the manual rod. It would still get some water in from deep water, but at least the end bell would be sealed and weep chamber able to drain. You might have survived a quick submersion if the mods had been done.

[SteveWolf]

Originally Posted by booster

What model of van do you have.

The motor likely filled up through the non drive end bell cap, which would have been modified to allow the spring loaded manual free up rod. There is no effective seal on that area and it is directly into the motor housing. The cap on that bell over the shaft is solid and gasketed from the factory for just that reason.


The other big issue is that the pump is upside down, so any water that get into the intermediate gap chamber between the pump and motor wont drain ....

I saw that "upside down" issue when I tore it down. Four years and that hasn't been an issue yet. I am going to ignore that one.

The screw rod hole is the issue.

Did you see my comment on using a piece of silicon tube on the rod? Seal the silicon to the macerator screw hole that allows access to the rotor. Seal the other end a foot or so out with a tight zip tie. Now I can use the rod but it remains sealed.

Thought?

Thanks,
Steve

[booster]

Originally Posted by SteveWolf

I saw that "upside down" issue when I tore it down. Four years and that hasn't been an issue yet. I am going to ignore that one.

The screw rod hole is the issue.

Did you see my comment on using a piece of silicon tube on the rod? Seal the silicon to the macerator screw hole that allows access to the rotor. Seal the other end a foot or so out with a tight zip tie. Now I can use the rod but it remains sealed.

Thought?

Thanks,
Steve

I think you will find it very hard to seal the tube as something has to be able to rotate, and thing bounces all over the place, I looked at that a bunch and finally just sealed it. A single seal with limited at best support is not likely to seal well at all. I never had an occasion to need it in nearly a decade, anyway. If they are stuck that tight, you are probably going to rip the vanes off anyway as they have to flip over center when you try to force it backwards. I simple reversing switch on the 12v power will also work, I think.


You may have not had any problem with top weep hole issue, but you likely will as nearly all the pump seals will leak eventually unless something else happens. Once exposed it takes about a minute to drill and new hole in the bottom and silicone the top one.

[SteveWolf]

Originally Posted by booster

.... I simple reversing switch on the 12v power will also work, I think. ....

WHAT A FRIGGIN' AWESOME IDEA!

This is the reason to be here!

Steve

[SteveWolf]

Here's some pictures:

Sealing a macerator

[avanti]

Sealing machinery with moving parts is generally a fool's errand. More often than not you end up just creating moisture traps that never dry. This is why weep holes are important.

[magicbus]

If you live or visit often an island thirty miles out in the Atlantic you will drive in salt water.
I live on an island 30 miles out in the Atlantic but we use a ferry to get here rather than drive through salt water. In fact I’ve lived on islands in the Atlantic for 30 years in NE, NJ and the FL Keys and we have a saying when watching someone drive in salt water... must be a lease. I always waited for low tide.

Salt water kills brakes, U-joints, sensors and other important parts of a vehicle. I would suggest your macerator pump may be the least of your problems.

[booster]

Originally Posted by avanti

Sealing machinery with moving parts is generally a fool's errand. More often than not you end up just creating moisture traps that never dry. This is why weep holes are important.

This is a good point and in the case of the macerator the weep hole in the center chamber of the pump would hopefully work as the breathing port, depending on the design of the shaft seal to the motor. The motor is going to heat and cool down so the air will expand and contract so has to be able to move. That air needs to come in at a point that has no water on it or the water will get sucked in.



If the motor is covered in plastisol there will be more possibility of overheating it as that is a good insulator. I would only put it on the seams or other small openings.

[SteveWolf]

Originally Posted by booster

This is a good point and in the case of the macerator the weep hole in the center chamber of the pump would hopefully work as the breathing port, depending on the design of the shaft seal to the motor. The motor is going to heat and cool down so the air will expand and contract so has to be able to move. That air needs to come in at a point that has no water on it or the water will get sucked in....

That's why one asks questions here. I never thought of the motor's need to breathe. The duty cycle of a maybe two minutes on and a long time off also plays into this.

Macerators are in failure mode when you put them in. You get a few years with them and then can be sure you'll have to replace it.

Calling the three-eights inch port that allows one to manually turn the rotor a weep hole is pushing it. I just checked to find there is no other weep hole in motor. Sealing the rotor port will seal the motor.

The calculus might be answering the question as to which leads to a longer time between replacements: Having a hole that allows water ingress or sealing the unit and dealing with the affects that brings.

I do remember seeing weep holes that had some sort of valve-like protection.

[booster]

Originally Posted by SteveWolf

That's why one asks questions here. I never thought of the motor's need to breathe. The duty cycle of a maybe two minutes on and a long time off also plays into this.

Macerators are in failure mode when you put them in. You get a few years with them and then can be sure you'll have to replace it.

Calling the three-eights inch port that allows one to manually turn the rotor a weep hole is pushing it. I just checked to find there is no other weep hole in motor. Sealing the rotor port will seal the motor.

The calculus might be answering the question as to which leads to a longer time between replacements: Having a hole that allows water ingress or sealing the unit and dealing with the affects that brings.

I do remember seeing weep holes that had some sort of valve-like protection.

I think we may have some miscommunication on "holes". The weep hole we are referring to is a very small hole at the top on yours, should be on the bottom, in the intermediate chamber between the pump and motor. The only real reason that chamber is there is to prevent minor pump leakage from going into the motor. Any minor leakage, which comes way before pump failures in most pumps, will just drip out the hole if it is on the bottom. If the hole is on top the chamber fills with water and when it gets to shaft level goes right into the motor. The secondary thing it can do is breath air for pressure changes in the pump.


The big hole in the end bell cap for the rod is not there on stock pumps, at least the ones I have seen. That was an ill advised thing that Roadtrek did, and Shuflo says that area would have to be completely protected from any water with the hole in there, from when I talked to them about both the upside down and big hole questions. They have a solid cap on them that is gasketed so would considered sealed if done right. Without that big hole, the motor can only breath through the weep hole or any gaps in the fit of the motor parts. Here is a quote from the manual on accessing the motor shaft to clear jams.

REAR END CAP/ MOTOR SHAFT SLOT ACCESSLoosen end cap screws (17). Rotate shaft cover (16) to access slot on motor shaf

[SteveWolf]

Originally Posted by magicbus

I live on an island 30 miles out in the Atlantic but we use a ferry to get here rather than drive through salt water. In fact I’ve lived on islands in the Atlantic for 30 years in NE, NJ and the FL Keys and we have a saying ....

Lucky you! After Hurricane Dorian you'd be stuck home for about two weeks depending on where on Hatteras you lived. It took a very long time for that water to recede.

The brine and salt they drop to melt snow in Ohio makes a fine batch of salt water. The salinity of salted roads was on par with ocean water until they started dropping brine. Now it is often a bit saltier. Staying out of that saltier water would be quite a trick. And it would eliminate winter camping which is completely unacceptable!!!

[avanti]

Originally Posted by SteveWolf

Macerators are in failure mode when you put them in. You get a few years with them and then can be sure you'll have to replace it.

I dunno...
Over two vans and 14 years, I have never had a macerator failure. Of course, that is just a sample of two, so it doesn't mean that much. However, I do have an unsupported theory that many macerator failures are due to improper winterization. I wonder how many people actually remember to thoroughly fill their dump line with pink stuff as part of their winterization regimen.

[booster]

Originally Posted by SteveWolf

Lucky you! After Hurricane Dorian you'd be stuck home for about two weeks depending on where on Hatteras you lived. It took a very long time for that water to recede.

The brine and salt they drop to melt snow in Ohio makes a fine batch of salt water. The salinity of salted roads was on par with ocean water until they started dropping brine. Now it is often a bit saltier. Staying out of that saltier water would be quite a trick. And it would eliminate winter camping which is completely unacceptable!!!

We live in Minnesota so deal with salt all the time, also. I think we are talking about apples and oranges, though in speed of problems coming.


Immersion is completely different than splash salt water, as it will get into places when submerged that it will not get to when splashed. Splash guarding is absolute cake compared to immersion sealing.


To immerse, you need positive seals which also means that can't be allowed to breath air, at all, ever, under any circumstances. That necessitates that the device needs to be somehow vented or designed to hold pressure and vacuum at all the temps it will see. Most "sealed" bearings have a positive seal on them but are able to release a bit of pressure so are not rated for submersion. It is still best they be vented though. Essentially all the seals on the wheel bearings, axle bearings, starters, alternators, etc on vehicles will not handle submersions.


The single worst thing that can happen with a normal sealed bearing is to have it hot from going down the road, and some bearings like the outer axle bearings on the 9.5" semi floating Roadtrek rear axle get very hot at 150*F or more, and then getting that bearing into water. The water quickly cools the bearing so the air in it contracts and pulls air in through the seals in most cases, our through a vent if there is one (some hubs, all rear axles, I think). If there is water where air is coming in, all water goes in and will destroy things pretty quickly, especially if it is salt water. Axles used to have just a vent cap on the top of axle shaft, but most now using a fitting and tube to a higher spot for just this reason. Of course about half of the axles I have seen had the tube rotted off, missing, or hanging down so that can be an issue. The trans of the Chevies also has a tubing vent that goes up into a clip in the doghouse to hold it high. Whenever you do anything under there you need to make sure you don't disturb it.



The best example of what can happen was not on a motor vehicle, but on a lawn tractor we had. 48" deck had single lip sealed bearings, not greaseable, that ran pretty hot in summer. We used it for something like 5 years with a bearing failure on the deck. My stepdad took over mowing when he retired, as he liked to mow and had been working at a golf course. Unknown to us, instead of blowing of the tractor when he was done with compressed air, he used the garden hose to rinse it down. The first summer it went through 6 bearings. When I saw the rust in the bearings, I asked him if they were getting wet, and that is when we found out about the water. He shifted to the air hose and no bearing failures after that. Cold water on hot bearings on the top flat surface sucked in water and rusted. The lower also got damaged a bit, but only after the top bearing was nearing failure and seals popped out letting water all the way to lower bearing.

[SteveWolf]

Originally Posted by booster

I think we may have some miscommunication on "holes". The weep hole we are referring to is a very small hole at the top on yours, should be on the bottom, in the intermediate chamber between the pump and motor. The only real reason that chamber is there is to prevent minor pump leakage from going into the motor. Any minor leakage, which comes way before pump failures in most pumps, will just drip out the hole if it is on the bottom. If the hole is on top the chamber fills with water and when it gets to shaft level goes right into the motor. The secondary thing it can do is breath air for pressure changes in the pump ....

Thank you Booster! Now I understand and flipping it does make sense.

[booster]

Originally Posted by avanti

I dunno...
Over two vans and 14 years, I have never had a macerator failure. Of course, that is just a sample of two, so it doesn't mean that much. However, I do have an unsupported theory that many macerator failures are due to improper winterization. I wonder how many people actually remember to thoroughly fill their dump line with pink stuff as part of their winterization regimen.

Very true.



I also think there is one other often not done thing that can cause failures early.



Many folks will run the pump too long after it is nearly empty and pulsing, which is not good for the pump and it also gets most of the water out of the pump chamber. That doesn't mean it gets all the "stuff" out of the pump, though, so if there is air in the pump and piping when sitting the "stuff" can dry out and stick the impeller to the housing. As soon as you start the pump it either won't turn or rips off some of the impeller vanes.


The easy prevention is to make sure you either leave the black tank valve open when you are your additive (if you use one) and water to the tank, and then close it, or you can close it after pumping and just open the valve after adding water to the tank which is what we do. This fills the valve backsides, piping, and pump chamber with additive, or not, treated water so nothing gets a chance to dry out, get sticky, plug things up.

[GeorgeRa]

I had electrically driven scissor jack levelers on my trailers. DC motors were very exposed to splashing water and I needed to clean them often. To remedy the problem, I added a rubber boot / cap with hose clamp. Cut its side to allow wires to go through and sealed the cut after mounting with a tape. It wasn’t perfect but it definitely reduced water intake. I don’t have a picture of the remedy but have some pictures illustrating the problem I sent to the unresponsive manufacturer. The primary leak was through the rear end with brushes.

https://www.homedepot.com/p/The-Plum...-305860715-_-N

I had some experience with impeller positive displacement pumps pumping sea water to engine cooling heat exchangers on our boats. Certainly, more critical application than draining a black water tank. My routine was to replace these impellers once a year. They don’t like running dry and extended storage can cause these impellers to take a shape.

[Mexray]

Couldn’t agree more... when I drive on the beach to camp, when back home, I always run my rig back & forth for quite a while with my fresh water sprinkler washing the undercarriage...