I have cable operated Valterra/Bladex dump valves that failed to operate. I know that the cable type can be troublesome, so I explored the reason for the hard operation. I found the cables were not the issue, they moved freely. It turns out that the blade seals pipe to pipe just fine but there is no seal to keep "stuff" out of the area where the blade is when retracted. I sawed the valve apart to verify the fact and it was a mess in there. Given the fact that buildup is inevitable, the life of this type of valve is limited. Of course a direct rod operated one can be used till operation becomes extremely difficult, but a cable will buckle. I installed tubing from the inside of the new valve and ran it along the cable. If operation begins to stiffen, I will shoot silicone or something into the valve.If there is a better design out there, please let me know. It appears the electric models just use the faulty design.

Well of course there are better valves. But probably aren't ones that you will be buying. Generically that sort of valve is a "knife edged gate valve". And there are a multitude available in industrial catalogs: McMaster-CarrThose are heavy metal ones and a bit pricey you'll notice. But they do have PVDF seals. Most valving of this sort shows up in the manufacturer's specialty catalog and not general catalogs. They are available in many materials from engineering plastics thru exotic alloy's like Carpenter-20. You can get all sorts of operators from handwheels thru electric or pneumatic operators. Some examples:imagesWhen I was buying things like this we thought nothing of spending $600 or more for a small 1 inch valve. The prices go up rapidly when you add options.Just remember that: "An engineer is someone who can do a $100 job for $10" and that's why the valves on RV's are not top of the line. They do the job at a low cost.

After dumping... could a person disconnect the dump hose, then leave the gate valve open and flush back up in the area with a forceful large volume of water? Is there any way to access it?I've never examined one of these in detail. Just wondering if it could be done.

Also why it is important to flush some clear water down after pulling the valve. You need to wash any cling on's off of the valve. That will keep the valve and seat clean and working easy. Plus it helps avoid the leakage that sometimes happens when the valve does not fully close and you get a surprise when you remove the end cap to dump.

coolmom42 wrote:After dumping... could a person disconnect the dump hose, then leave the gate valve open and flush back up in the area with a forceful large volume of water? Is there any way to access it?I've never examined one of these in detail. Just wondering if it could be done.There are elbows and extensions with hose attachments for backflushing. Get a clear one and you can see what comes out.There is also an end cap valve which is useful if leaks happen.

The usual cause of debris in the valve body cavity is the practice of LEAVING the valve OPEN while camped. This allows the slower moving liquid/solids to fill into the normal gaps in the valve cavity. When you dump a tank with liquid in it, the rush of debris/water is enough to keep the debris from settling in the valve cavity. Once the debris is in the cavity, there is NOTHING to do except pull the valve and manually clean it out. Cable operated valves, it is easier to clean out once the valve is pulled. Rod(Handle) driven valves are harder to clean because the odds are the debris has been FORCED into the valve body because you can push harder and the cable will just flex. But, backflushing or trying to install a chemical will not get rid of the debris in the valve body. You have to dig it out with a screwdriver. Doug

Is there a better dump valve? | Good Sam Community

23 Replies

NMDriver
Explorer
Jun 02, 2017
Also why it is important to flush some clear water down after pulling the valve. You need to wash any cling on's off of the valve. That will keep the valve and seat clean and working easy.

Plus it helps avoid the leakage that sometimes happens when the valve does not fully close and you get a surprise when you remove the end cap to dump.
coolmom42
Explorer II
Jun 02, 2017
After dumping... could a person disconnect the dump hose, then leave the gate valve open and flush back up in the area with a forceful large volume of water? Is there any way to access it?

I've never examined one of these in detail. Just wondering if it could be done.
agesilaus
Explorer III
Jun 02, 2017
Well of course there are better valves. But probably aren't ones that you will be buying. Generically that sort of valve is a "knife edged gate valve". And there are a multitude available in industrial catalogs: McMaster-Carr

Those are heavy metal ones and a bit pricey you'll notice. But they do have PVDF seals. Most valving of this sort shows up in the manufacturer's specialty catalog and not general catalogs. They are available in many materials from engineering plastics thru exotic alloy's like Carpenter-20. You can get all sorts of operators from handwheels thru electric or pneumatic operators.

Some examples:images

When I was buying things like this we thought nothing of spending $600 or more for a small 1 inch valve. The prices go up rapidly when you add options.

Just remember that: "An engineer is someone who can do a $100 job for $10" and that's why the valves on RV's are not top of the line. They do the job at a low cost.

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Is there a better dump valve?

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