Carver 356 Tank Watch System

R

reelpriority

Member
Joined
Apr 13, 2013
RO Number
33227
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40
1999 Carver 356 has three light Tank Watch system in forward and aft heads. I suspect that the Tank Watch probes are reading incorrect. The forward holding tank has access to the top of the tank to remove the probes for cleaning or replacement. The aft holding tank probes are under the fiberglass floor and cannot be accessed without cutting a circular hole in the floor above the tank. Has anyone had this problem and determined a better solution. Checking the holding tank level with a flashlight is getting old and requires rolling up carpet and removing a hatch in the aft stateroom.
Thanks
 
RP, my aft tank monitor is also not working and you are correct, the access is non-existent. From talking with others you need to slide the tank out to replace the sensor. I would make an access hatch as you suggest. I have not done it but have thought about it. I will need to at some point. I did remove and clean the forward sensor last summer, it helped the accuracy. Good luck and let me know if you solve this issue.
 
I too had tank monitor problems. I found that my probes were sticking out of the tank too far. I was able to loosen the plastic nut holding them tight and push them back down until the rubber cover almost touched the plastic nut. The monitors are working great now.
 
So all you did is loosen the small plastic nuts that have wire hook to them and push it down and it worked. I hope your right going to give it a try.
 
Finally was able to open up the forward holding tank access plate with the Tank Watch III probes. Used a 15" Channel Lock Oil Plier wrench.....worked great to loosen the cap. Probes looked bad. One was actually broken and twisted to the side between the other two probes. This is a 12 year old probe and probably was never cleaned by the previous owner on this 1999 Carver 356.
I called a Sealand dealer and ordered a new probe assembly. Not cheap...about $160.00 just for the probes and cap (no vent). All the wires will need to be joined with new butt connectors to the Carver wiring harness. The probes that are stocked by the dealer are either 22" or 45". I will need to cut down the 22" to equal the factory installed probe. I called Carver and they agreed that this was the only solution for the Tank Watch system. Carver now uses sensors on the new boat ( a special metal tape that is applied to the outside wall of the tank to sense the various levels). Nothing is simple!!!!!
 
The tank monitor system on my Carver Santego has also gone to sh!t. I've heard on this forum many years ago that Snake River makes an awesome and affordable tank monitoring system. I plan on buying a 2-tank monitoring system that utilizes the foil sensor on the outside of the tank rather than the in-tank probes/sensors. I plan up updating mine to monitor the fresh water tank as well as the holding tank. Cost is about $160 for the entire system-maybe an option for you? Snake River was bought out by Tech-edge but if you google snake river tank monitor, it will come up.
 
Just completed installation of new Tank Watch III probes in forward holding tank in 356 Aft Cabin. Carver had a factory wiring harness which I used cutting off the old Tank Watch Probes and installing the new probes. Needed to measure and cut down the new probes to fit the tank for empty and mid levels. Good opportunity to flush out the holding tank with fresh water. New probes work fine. Now plan on changing out the stern holding tank probes.
 
RP, where did you buy the Tankwatch probes from? Were you able to just get the probes alone? Thanks JB
 
CV: The Sealand part number is: 313000355 which is the 3 probes, cap, (non-vented), and the wiring. The empty and mid tank probes are 22" long which requires cutting the tubes with a plumbers pipe cutter (real easy). There are instructions from Sealand on how to complete the installation. Carver has a wiring harness which allows you to unplug the Tank Watch cap/probe assembly. You will need to cut and re-wire with six heat shrink butt connectors to install the new probes. I would empty the holding tank before you tackle this job. I also disconnected the holding tank vent hose and used a compressor to make sure the vent line going to the port side vent fitting was clear. You may have to move the shower sump to get to the vent hose and gray 90 degree fitting. I found that the fitting was partially blocked with waste from the previous owner. Fitting unscrews easily and can be flushed/cleaned. The change over can be a big project. The end result was that the system is now operating correctly with accurate tank level lights. Aft tank is next on the list.
You can google the Sealand part. Lots of different prices. I bought from the Sealand distributor in Ft. Laundedale: Environmental Marine Services Inc. I have since seen lower prices around $118.00 prior to shipping/handling. Environmental Marine Services charged list price at $156.58.
 
Be careful what type of solution you use in your tank. I had a new sensor assembly in my front tank, and cleaned and repaired my aft tank sensors two seasons ago. By mid season last year they both were not working right again.
I was using the blue stuff, which I don't think breaks down solids well, as soon as solids get in the sensors they don't work again.
This year based on info from this site, I'm trying Odorlos. It is supposed to break things down better. We will see.
 
VT: thanks for the " heads up" on the holding tank treatment. I have been using Odorless product. Can't say if it the best option. A lot of good comments on forums.
How did you get access to the aft tank sensors. I don't have an access hatch above the Tank Watch probe circular cap. I may need to cut an opening an install a deck plate under the carpet.
 
I had no choice, my aft sensor assembly was broken. After every flush we were getting bad smells, so I sprayed soapy water around the tank and found it was leaking out air around the sensors.
What I did disconnect all the lines to the tank, cut the straps holding it down, and slid the tank back towards the opening. I was able to get it back far enough to remove the cap and sensor assembly. Not a fun job, and not one I want to do again. Before launch this season I filled each tank with 4 gallons of vinegar and then water, hoping to break up any stuff stuff on the sensors. Now using odorlos. Hoping it will revive my sensors, too early to tell yet.
 
Thanks VT. I think the only option with these in tank probes is to resign yourself to a maintenance schedule pulling the probes out and flushing them. The wiring harness connection simplifies the removal from the tank. The aft tank does need a hatch which is what the local marine sanitation folks said they would do versus moving the entire tank. Make sure your vent lines are clear, especially the gray 90 degree fitting. The tank needs air to help the waste break down. These lines can clog easily if the tank is over filled.
Carver now uses the foil tape sensors mounted on the outside of the tank. I had one of these on another Carver and it worked great for black water and the fresh water tank.
 
Thanks guys for all the info....I think I'll just sell the boat, seems l like a lot of work :)
 
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