waste valve wont open

Busnut83 · December 05, 2011, 10:13:04 PM

Got the prevost home and went to empty the waste tank. 98xl, the switch is behind the drivers seat.... open or close the valve does nothing... is it air operated??? and can I manually open it???

prevosman · December 06, 2011, 04:29:56 AM

First, the best responses will be posted if you can be more specific such as telling who the converter was.

But to answer the question specifically, look at the dump valve. If it has a handle it is manual, and if it has an air cylinder or electrically operated actuator it operates via the switch. More generalizations: If it is air, is the bus aired up?

While remote switches are offered on some conversions, it is probable there is a dump valve switch in the bay right over or near the dump valve. Before you start messing with anything however, make sure you have the sewer hose connected.

A dump valve that has not been operated in a while is going to drag, or be hard to open. Assuming it is a powered valve keep the switch in the open position and give it a little time. If that doesn't do it, and you are sure it is getting air or electric or both you next have to verify the valve itself is trying to open. It could be the signal from the switch isn't opening a valve or actuating the electric opener. You can always disassemble the actuator from its mount and using that as a handle pull up on the valve to open it.

But on a very serious note please understand what I am about to say is trying to be helpful. If you don't know if a dump valve is air operated or if you can manually open it it indicates to me the complexity of a Prevost conversion is going to overwhelm you. I would urge you find other owners of your type conversion and establish communications with them so you can get help and advice as you learn the coach. Most "problems" tend to not be real problems but a lack of owner understanding. In your case it sounds like you may have a steep learning curve ahead of you.

robertglines1 · December 06, 2011, 04:51:32 AM

although prevoman; sounded a little tough --he is rite-- differant converters did it in differant ways. My coach was converted in the south(name omitted ) and was not up to my standards. Lamp cord was used as well as other short cuts. Not very professional! I got real deal so I have no problems because I am doing total systems rebuild. My particular coach was a group built under revision 21 and has 4 luggage bays. If yours is the same type let me know. The prevost part of the coach is up to their Quality. Bob

luvrbus · December 06, 2011, 05:02:03 AM

If you have the Drain Master valve there is a manual override a slot head in the valve to turn with a screw driver be careful not to strip the slot head,they are electric.
I think I know the bus you bought the school here was trying to deal on it and someone from the Dallas area paid more than they were willing to pay was that you ?

good luck

Busnut83 · December 06, 2011, 05:55:08 AM

Yes the bus is aired up. No I dont know the converter. there is two lines i think are air connected to a cylinder. there is a pull handle that could be manual but with slight pull would not open. The bus was purchased on Ebay from Delaware Truck in Columbus,Ohio. Great Guy.... Stopped at Creative Interiors in Columbus an was told the converter was not known and the bus could have been a motorhome or entertainer prior. My experience here is ask or search because the knowlege and many experiences.... I am not trying to reinvent the wheel...

Joe Camper · December 06, 2011, 05:59:53 AM

If it is air it may very well have push in type fittings at that valve. If so you will ALWAYS have air either on 1 side of that valve or the other.

With the waste hose hooked up pull those 2 lines off 1 at a time. If air is present at either one of them switch them and either the gate will open or it is stuck.

If no air is present at either line there is a control signal that is not present that should be.

luvrbus · December 06, 2011, 06:23:56 AM

Same bus we never knew it was on Ebay just told someone in Dallas bought it was a entertainer shell and our guy said it needed front end work that was a month ago it's supposed to have a fairly recent series 60 rebuild but WW Williams was unable to verify it through the DD network congrats on the purchase

good luck

prevosman · December 06, 2011, 08:23:33 AM

Busnut,

If you can verify it is getting air (full aux pressure which should be around 125 PSI) if it does not open I think it is a safe assumption the gate is sticking. You can loosen the air cylinder at the base and pull up on it using it like a manual valve handle.

If you are afraid of putting too much force on it perhaps you can disconnect it (likely a threaded fitting where it attaches) and use a slide hammer to jar it loose. A holding tank valve that sits for a while almost glues itself in place. It is sliding like a knife between the seals and any crud in there just seems to bond the gate closed. On mine which is used regularly the first time I operate the valve after it has sat in the garage for a while takes a few seconds for the pressure on the air cylinder to pop it open. I imagine if it sat for a long time it just needs to be exercised. I occasionally use white grease on my seals if the valve gets cranky.

Joe Camper · December 06, 2011, 09:33:52 AM

Does it have a black hard plastic ball bout the size of a golf ball at the top of the stem?

Does it say Dupree on the side somewhere?

If so there will be 2 phillips head screws screwed down into the housing on either side of the stem. Remove those 2 screws and pull the entire thing out of the housing. The blade or gate or whatever you want to call what is going up and down is tapered like a spearhead on the Dupree. These are easy to fix

prevosman · December 06, 2011, 09:51:44 AM

I think the object here is for busnut to avoid a s**t bath. Just saying.

Joe Camper · December 06, 2011, 12:35:52 PM

Well I was assuming some I suppose.

There are 2 different type air dumps. 1 is like what you have Prevoman a standard valve that originally comes with a black plastic t handle that is threaded on the stem that gets removed and a air cylinder is threaded on in its place.

The other has the air cylinder incorporated into the housing of the valve itself. The stem still retains its knob in most cases black and round and the air lines come out the side of the housing. This type can be manually opporated simply by removing the air lines and puling up on the knob. remove the 2 top screws and the whole gate comes out. The gate on this type is also tapered it goes from like 3/4 in thick at the top to a point at the bottom, rubber on both sides.

Dupree is often the manufacturer I have seen them on both motorhome and entertainer conversions.

The seals for the ones you and I have you can get from Aurora air products. My step slide cylinder I also fixed with Aurora's help, same stuff just longer.

Busnut83 · December 14, 2011, 09:30:18 PM

thanks joe you are right... working on this now... got it open.... thanks...

gcyeaw · December 15, 2011, 06:40:59 AM

If it is a Dupree valve here is where to get the parts.

http://www.dupreeproducts.com/SearchResults.asp?Cat=1

desi arnaz · December 15, 2011, 10:37:15 AM

personally i would say he is full of sh*t........