Boxxer 421 fresh water invading my waste tank help

Randy Herman

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So i was cleaning yesterday, just a 3 bedroom and I ran out of water. My fresh water tank was full when i left and obviously it doesn't take 80 gallons to clean 3 rooms. I pulled the lever on my waste tank, which was empty to start the day and clean water just poured out of it. All 80 gallons from my fresh water tank. It was fine the day before, so I am confused to what may be causing this. Any help would be greatly appreciated,
 

SRD

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its possible if the thermal valves wide open coming into the waste tank or plumbed close to the blower filter in the tank, but water coming out of the exhaust in any noticeable quantity isnt normal. you might get a little at first before it gets up to temp or if your tanks close to full as mentioned above but other than that there shouldnt be water coming out of the exhaust.
 

wandwizard

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The above suggestions are on track. It is either the thermal relief valve or the Dema high pressure solenoid. Either one can cause your waste tank to fill up pretty quick and use all your fresh water. You will definitely notice a LOT of heat loss if it's the solenoid, but not near as noticeable if it's the thermal valve. The solenoid is actually dumping your hot water into your waste tank when it goes bad. The thermal valve is dumping the water from the water box so the water in there will never get too hot.

There is a line coming off the thermal relief valve that goes back to the waste tank and should join at the same place the solenoid is at. Clamp that off and see if the water dumping stops. If it does not stop it you know it's the solenoid. If your water still seemed pretty hot while you were cleaning I can almost guarantee it is the solenoid is either stuck open or the 12 volt coil on it has gone out so it's staying in the open position all the time and continuously dumping your hot water. I strongly suggest keeping an extra thermal valve and solenoid on hand for Boxxers.
 
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Randy Herman

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The above suggestions are on track. It is either the thermal relief valve or the Dema high pressure solenoid. Either one can cause your waste tank to fill up pretty quick and use all your fresh water. You will definitely notice a LOT of heat loss if it's the solenoid, but not near as noticeable if it's the thermal valve. The solenoid is actually dumping your hot water into your waste tank when it goes bad. The thermal valve is dumping the water from the water box so the water in there will never get too hot.

There is a line coming off the thermal relief valve that goes back to the waste tank and should join at the same place the solenoid is at. Clamp that off and see if the water dumping stops. If it does not stop it you know it's the solenoid. If your water still seemed pretty hot while you were cleaning I can almost guarantee it is the solenoid is either stuck open or the 12 volt coil on it has gone out so it's staying in the open position all the time and continuously dumping your hot water. I strongly suggest keeping an extra thermal valve and solenoid on hand for Boxxers.
This is the problem hose.
 

Randy Herman

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028F3FDB-24D8-488F-B61C-AE8B90B95299.jpeg
 

Randy Herman

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I disconnected it and it blew water everywhere. Can I run this back to the fresh water tank for a day until I can figure out how to fix it and get the part here or would that damage something. Sorry there’s no place that works on these by me so I’m learning to fix as it breaks
 

wandwizard

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I disconnected it and it blew water everywhere. Can I run this back to the fresh water tank for a day until I can figure out how to fix it and get the part here or would that damage something. Sorry there’s no place that works on these by me so I’m learning to fix as it breaks

Do you mean the hose itself is leaking or that you took it off and it squirted water everywhere? That is the hose that is connected to your Dema solenoid and that's where your machine controls the temperature of the heat exchange water. It is always under pressure when the machine is running so it cannot be disconnected while the machine is running. The solenoid is controlled by the temp control on the machine and opens to let hot water into your waste tank. When the coil goes out on those solenoids it remains in the open position so your hot water is getting dumped the whole time the machine is running. I put a shut off valve on mine in case that happens and simply leave the diverter off until I can get it fixed.

Btw, that larger hose next to it is where your thermal valve releases water into the waste tank. I did re-route that hose to my fresh water tank years ago so if it happens to go out in the middle of a job it doesn't cause me any problems at all other than a little lost water temp. I do not think it's safe to re-route the solenoid water though cause it's too hot and could cause you some problems.

If you take your tank lid off and turn the machine on you will see where they both dump water into the waste tank.
 
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Randy Herman

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Do you mean the hose itself is leaking or that you took it off and it squirted water everywhere? That is the hose that is connected to your Dema solenoid and that's where your machine controls the temperature of the heat exchange water. It is always under pressure when the machine is running so it cannot be disconnected while the machine is running. The solenoid is controlled by the temp control on the machine and opens to let hot water into your waste tank. When the coil goes out on those solenoids it remains in the open position so your hot water is getting dumped the whole time the machine is running. I put a shut off valve on mine in case that happens and simply leave the diverter off until I can get it fixed.

Btw, that larger hose next to it is where your thermal valve releases water into the waste tank. I did re-route that hose to my fresh water tank years ago so if it happens to go out in the middle of a job it doesn't cause me any problems at all other than a little lost water temp. I do not think it's safe to re-route the solenoid water though cause it's too hot and could cause you some problems.

If you take your tank lid off and turn the machine on you will see where they both dump water into the waste tank.
No when I disconnected it. The hose is fine. What I meant about rerouting I meant leave it hooked up at the bottom and put the hose in the actual fresh water tank so it shoots in there instead. Could I just run it with the diverted button off until I get a new solenoid or does it not work that way
 

wandwizard

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No when I disconnected it. The hose is fine. What I meant about rerouting I meant leave it hooked up at the bottom and put the hose in the actual fresh water tank so it shoots in there instead. Could I just run it with the diverted button off until I get a new solenoid or does it not work that way

Yes I think you could, but your water will never get hot. What I did with mine is to put a shut off valve between the solenoid and the waste tank. That way if the solenoid goes out I can shut it off and leave the diverter off. When you leave the diverter off and turn the temp dial all the way up to 250 the solenoid will not ever get activated anyway. It will get you by until you figure out the problem or replace the solenoid. A lot of times it's just scale build up inside the solenoid causing the problem and cleaning it out fixes it. They are not really too complicated and there is a diagram showing how the inner parts should go if you need to do that let me know. Here's what mine looks like with the shut off valve.
20181027_192807.jpg
 

Randy Herman

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Yes I think you could, but your water will never get hot. What I did with mine is to put a shut off valve between the solenoid and the waste tank. That way if the solenoid goes out I can shut it off and leave the diverter off. When you leave the diverter off and turn the temp dial all the way up to 250 the solenoid will not ever get activated anyway. It will get you by until you figure out the problem or replace the solenoid. A lot of times it's just scale build up inside the solenoid causing the problem and cleaning it out fixes it. They are not really too complicated and there is a diagram showing how the inner parts should go if you need to do that let me know. Here's what mine looks like with the shut off valve.
View attachment 80831
Nice, I was just trying to get through a small job tomorrow then I can get into it more. So I I clean it out and doesn’t fix it this is what I need93CA9299-0F75-48E0-8454-8206F74F2C07.jpeg
 

wandwizard

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Nice, I was just trying to get through a small job tomorrow then I can get into it more. So I I clean it out and doesn’t fix it this is what I needView attachment 80832

If you clean it out be careful. I'll give you a link that shows how the insides go together. If cleaning it out doesn't solve the problem chances are the 12 volt coil has gone out. That's kind of rare, but I've seen 2 or 3 go out in 16 years. It is best to go ahead and buy another solenoid and keep the old one for spare parts. You can just buy the coil, but I've never done that. They also sell a repair kit that has all the inside parts. https://shop.truckmountforums.com sells the entire solenoid, but they way over charge for it. I suggest buying from either Kleenrite or Dultmeier. The solenoid model is a 12 volt high pressure normally closed model 453P. They sell a LOT of different types so this is VERY specific. Here is the one from https://shop.truckmountforums.com so you know for sure what to ask for. https://https://shop.truckmountforums.com/solenoid-high-temp.html

Here is a .pdf with some helpful info that shows that diagram too. You may need it if you clean it out. https://www.kleen-ritecorp.com/images/KleenRite/Manuals/DemaEngineering/SOD453P12/453P 453S 454P 458P 458PS Installation Instructions.pdf
 

wandwizard

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Btw, are you certain it is the solenoid doing the dumping and not the thermal relief valve? Either one dumps into the waste tank at the same place and both dump a lot of water if they go out.