My plastic WEMA holding tank sensor is long failed, and I have finally had the inevitable overflow, and have spent the last two days cleaning up. You may imagine my white-hot resolve never to do this again. I've read much in the archives about the Snake River sensors, and I know that Peggy likes them, but my metal tank has a 6-hole opening (not the NPT opening specified on the snake river site), and I have a WEMA guage. So, I thought I'd just replace the sensor with the original part, and get the little flush attachment that I've read about in the archives. When I went to the WEMA site, I discovered that the plastic WEMA sensors are now discontinued, replaced by an (apparently) sealed stainless-steel unit that fits into the same opening. Has anyone tried this new unit? Any reviews? I hate to reward the people who put me through the past couple of days, but I think I'm going to go with it, unless someone has a bad experience to share. I'll report back. Paul sv Escape Artist h336
Anybody have the new WEMA holding tank sensor?
- Thread starter Paul McGhee
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What's your tank made of?
If aluminum, a stainless sensor may create electrolysis that can accelerate the deterioration of the tank--which has a short enough life anyway. If plastic, the Snake River sensor goes on the outside of the tank...so you wouldn't need a different hole, you only need to put down a cover over the existing one which is easy to do.
If aluminum, a stainless sensor may create electrolysis that can accelerate the deterioration of the tank--which has a short enough life anyway. If plastic, the Snake River sensor goes on the outside of the tank...so you wouldn't need a different hole, you only need to put down a cover over the existing one which is easy to do.
only if the two metals touch
I believe my tank is aluminum, and I know it's 10 years old. I wonder why the aluminum tanks have such a short life. Do the welds crack? The galvanic corrosion should only occur if the two dissimilar metals come in direct contact with each other. I will make sure that they are isolated by gasketing, which would be necessary to seal the installation anyway.
I believe my tank is aluminum, and I know it's 10 years old. I wonder why the aluminum tanks have such a short life. Do the welds crack? The galvanic corrosion should only occur if the two dissimilar metals come in direct contact with each other. I will make sure that they are isolated by gasketing, which would be necessary to seal the installation anyway.
I got a stainless steel replacement
I replaced mine on my 1995 336 -- I called WEMA and they were pretty helpful. I replaced last winter and it still works.
I replaced mine on my 1995 336 -- I called WEMA and they were pretty helpful. I replaced last winter and it still works.
The problem is urine...
It's so corrosive that it typically eats through a weld at a seam or a fitting within 2-5 years and turns the tank bottom into a collander in about 10 years. Stainless lasts a little longer, but not much. That can vary a couple of years, but any metal tanks that are much older than 10 years only got that old because they weren't used till about 10 years ago. So you may have another problem you don't even know about yet! Urine also seems to set up electrolysis--which is not the same thing as galvanic corrosion--whether dissimilar metals contact or not... I've seen Sealand TankWatch senders completely eaten away--gone--in aluminum tanks. However...that may be because the TW senders have electrical contacts in them...when the level rises to the probe, it pushes up a little floating "collar" that completes the circuit to turn on the light. All in all, now might be very good time to replace both your gauge AND your tank with a plastic tank...especially since the weather is cooling off, making it much more pleasant job than it'll be if the tank fails in mid-summer.
It's so corrosive that it typically eats through a weld at a seam or a fitting within 2-5 years and turns the tank bottom into a collander in about 10 years. Stainless lasts a little longer, but not much. That can vary a couple of years, but any metal tanks that are much older than 10 years only got that old because they weren't used till about 10 years ago. So you may have another problem you don't even know about yet! Urine also seems to set up electrolysis--which is not the same thing as galvanic corrosion--whether dissimilar metals contact or not... I've seen Sealand TankWatch senders completely eaten away--gone--in aluminum tanks. However...that may be because the TW senders have electrical contacts in them...when the level rises to the probe, it pushes up a little floating "collar" that completes the circuit to turn on the light. All in all, now might be very good time to replace both your gauge AND your tank with a plastic tank...especially since the weather is cooling off, making it much more pleasant job than it'll be if the tank fails in mid-summer.
Metal 101
Any time that you weld aluminum or stainless steel, the welded area is no longer the same metal material. Impurities are part of the welding process and lead to the destruction of the metal in a corrosive atmosphere. This can be minimized by doing what is called heli-arc welding. That is, welding in a bubble of inert gas. This becomes an art form as the welder controls what happens to the metal as it is welded. Go plastic.
Any time that you weld aluminum or stainless steel, the welded area is no longer the same metal material. Impurities are part of the welding process and lead to the destruction of the metal in a corrosive atmosphere. This can be minimized by doing what is called heli-arc welding. That is, welding in a bubble of inert gas. This becomes an art form as the welder controls what happens to the metal as it is welded. Go plastic.
OK, sold.
I've got the panels removed and the tank completely exposed at the moment, sounds like a good time for a new plastic tank. Paul
I've got the panels removed and the tank completely exposed at the moment, sounds like a good time for a new plastic tank. Paul
I think you've made a wise decision.
A good quality plastic tank will last as long as the boat. Your best source is Ronco Plastics...their catalog is online at http://www.ronco-plastics.com. They make TOP quality thick-walled tanks for a very reasonable price, and hav more than 400 shapes and sizes--including over 100 non-rectangular--to choose from. And they install fittings in the sizes and locations specified by the customer when they make the tank. I also think you'll find the link below useful.
A good quality plastic tank will last as long as the boat. Your best source is Ronco Plastics...their catalog is online at http://www.ronco-plastics.com. They make TOP quality thick-walled tanks for a very reasonable price, and hav more than 400 shapes and sizes--including over 100 non-rectangular--to choose from. And they install fittings in the sizes and locations specified by the customer when they make the tank. I also think you'll find the link below useful.
preachin to the choir, girl
I've already got your book, with autograph, though I apparently need to re-read the chapter on holding tank product construction. If I see you at Newport this fall I'll stop and say hello. Best, Paul
I've already got your book, with autograph, though I apparently need to re-read the chapter on holding tank product construction. If I see you at Newport this fall I'll stop and say hello. Best, Paul
Not gonna make it to Newport this year...
Thanks for buying the book! The chapters you should re-read before tackling this project are "Installing a Head and Holding Tank" and "Replacing Hoses." Both provide step-by step instructions. Also "Holding Tank Odor--Odor Out the Vent"--before ordering a tank. As long as you're gonna do all this you might as well go all the way and replace all the hoses too. AVS96--what used to be sold as "SeaLand OdorSafe"--is the best and now that the mfr is selling it direct under their own brand name, down to $5/ft, cut to any length. Their website is at http://www.aussieglobe.com/avs96.htm
Thanks for buying the book!
The chapters you should re-read before tackling this project are "Installing a Head and Holding Tank" and "Replacing Hoses." Both provide step-by step instructions. Also "Holding Tank Odor--Odor Out the Vent"--before ordering a tank. As long as you're gonna do all this you might as well go all the way and replace all the hoses too. AVS96--what used to be sold as "SeaLand OdorSafe"--is the best and now that the mfr is selling it direct under their own brand name, down to $5/ft, cut to any length. Their website is at http://www.aussieglobe.com/avs96.htm- Status