Hey All, just bought a 1989 38' Grand Villa Osh Kosh with a Cat 3208T. We are super excited to go on our first RV trip tomorrow morning. This is my first RV purchase and while I'm extremely happy with what we got, I'm finding it's like purchasing a new home for the first time. There's just things I didn't think to check or test before handing the owner the check. Tonight, I went to sanitize the holding tank and while it was filling, I noticed water leaking in some places it shouldn't out of the bottom of some frame bolts. I immediately turned the water off and started to search. I finally found the culprit. Under the sofa on the drivers side was a T-off valve and out of that was a very small plastic pipe (similar to what's running to my water filter) that ran into about a foot long 2" PVC pipe capped at both ends and the pipe was threaded into one end. The cap had broken at one end and water was spilling out onto the floor. I fixed it by just turning off the valve and all is good. However, I cannot figure out what in the world this little reservoir is for? There is only ONE little tube going in and ZERO out. It looks like it just fills and sits there. The PVC reservoir was bolted with a U-bracket to the back of the front foot board on the couch. Does anyone know what this might be? I can easily build another, but I'm not sure what the purpose is? Thanks, Benjie.
Benjie,
Seems like that was a 1st generation surge tank, it just used trapped air without a diaphragm to dampen the the pump surge.. Hopefully James Holder will chime in he is the guru of the classics.
Welcome to the group
My 1989 36' Grand Villa with the ORED chassis has a new pump under the couch but no surge tank. There are two drain valves towards the driver's side wall. We do not notice any surging or "pounding"that would mandate a surge tank so I would recommend you try the system with the tank turned off. Also, look around behind the icemaker for a shutoff valve in the event you have the hot water preheat option. If so, shutting the valve turns the hot coolant off th the water heater but allows it to flow to the dash heater. I mention this because there was no mention anywhere in any of my manuals.
Thanks! I'm pretty sure you're right. I've replaced the surge tank just in case I needed it!
Hmmm, I'll have to check on that. I noticed two valves under the jack knife sofa, but I have no clue what they're for, do you? Just shutting off water to the bathroom and kitchen?
I saw a small shutoff valve under the kitchen sink that the former owner had installed when the ice maker was leaking, but haven't been able to look for the preheat option valve yet to see if I have it. I guess you would want it off in the case where you aren't using the hot water heater?
Under the couch: one valve is the drain for the hot water. The other is the drain for the cold water. At least this is how my valves were labeled when we bought the coach. Initially too far away to read the small print with my bifocals.
The hot water preheat option valve--in my coach-- is accessed by opening the rollup door below the sink, then reach in to the right, around behind the icemaker and down in a access "hole" cut into the right wall is a blue fretwork knob. This is the control valve for the water preheat valve. We drove from Northern Wisconsin to FOT without heat up front because we did not know about this valve. Wayne, at Fot, can do a show and tell on this. He works in the Alignment Shop at Foretravel.
I believe my '94 U225 is identical.
You folks are a wealth of knowledge already! I haven't had a chance to look yet, but will try and read the tags when I run out to the RV this week. I'm learning that I came into this pretty naive. I don't think we made a mistake just yet, but I'm realizing these older motorhomes are going to be a little more work than maybe I first realized! Our first weekend trip turned into a 12 hour nightmare (probably mostly due to my inexperience). Hoping we're through the rough patches and on to some fun! My kids want their dad playing with them, not head buried in some plumbing or electrical issue. Anyway, thanks again!
Oh, Oh, was I ever wrong!! I just came in from flushing the water system in prep for an outing. Guess what I found under the couch? A white PVC thingee with a tire valve on the top! Now that I know it is a surge tank, or as it is known up here as an anti-hammer air bladder, what should the air pressure be and how/when do I check it?
Check it with water system depressurized(no pump or city water on, one sink valve open) pressure should be 2 psi below rated water pump pressure.
Thanks Brett,
Your response then begs another question. How do I check the water pump pressure? I can check the air pressure using a standard tire gauge but how about the pump pressure?
Norm,
There is a discussion of accumulator pressure at Water tank pressure question (http://www.foreforums.com/index.php?topic=10489.msg49405#msg49405). It includes the method I used to set up the accumulator on my coach. There are also some alternate suggestions for appropriate pressures.
I'm can't remember if my busted hammer reservoir had a valve to read pressure. I don't think it did, but it was all busted up so I guess it could have. Is this something I should thread and install?
All I did was cut about an 11" long 3" PVC pipe, cap it at both ends, and then thread it for the water valve that was originally installed in the bottom.
Norm, I set mine at 29 lbs. I think that is a pretty safe pressure.
Kent, help me out here. Do I pressurize the surge tank after draining all water and leaving the drain valves open?
For bzeller: you will need a tire valve stem or equivalent on the top end of your new surge tank in order to introduce air into the tank.
Thanks Kent, Amos. You guys are helping more than just me by providing the info we need.
Brett, yes let all of the pressure out of the system to test the tank pressure and set it at the pressure you choose. If you have one of the fancier new high pressure pumps, you may want the tank pressure higher but I am very happy at 29 lbs.
OK, I can put one in, but I'm not sure I understand how to pressurize it? If I drain all the water and leave drain valves open won't I just be be pushing air through empty piping?
Good morning Kent and Benjie.
Same question as Benjie's. I don't think this surge tank has a rubber bladder in it like the tanks used on wells. So it must just use the air trapped in the PVC tube which is why it is mounted vertically like the ones in the walls of a home.
Some pictures would be really helpful.
It is just like the tank on a well pump in a stick house. Has a internal rubber bladder and the water only goes into it, not thru it. It give you water pressure when the pump pressure is low. Keeps the pump from running all the time. You need to pump air into that rubber bladder
I'll take some pics soon. FYI... I don't have a rubber bladder. All I had was a small T valve off the main pump line. The hose is a very small diameter plastic flex hose like you might attach to an ice maker. At the end of the hose, was a PVC pipe capped on both sides and the hose was threaded into the PVC. I didn't see the presto valve on mine, but it could have been there since it had basically exploded one end of the PVC cap when I caught it leaking all over.
Nighthawk, would love to see some pics of how yours looks if you get a chance to snap some.
OK, so here are the pics of what I have now. The first pic is the T-valve, second is the bottom where it enters the PVC chamber, third and fourth are pics of the chamber side and top. It sounds like I need to install a pressure valve into the top of the PVC chamber in order to pressurize it. I'm still not clear on how/when this is done. I would think you would do this with the water pipes pressurized either by the pump or city water. If not, then how else will the chamber retain pressure as I'm pumping air in?
Nighthawk, check it out! Found them all!
Couple questions.
1. For the cold and hot water drains, where do they drain to? Back into the holding tank?
2. WRT the water pre-heat valve, it says close for max dash heat. So if open, it basically helps the water heater be more efficient by not having to use as much propane to heat?
On the ground under the coach. At least that is where it should drain to. They drain the lower water lines.
I'll let someone else explain this. Afraid I'll get tongue twisted and mess it up.
The gate valve going the water heater, when open, sends engine heated coolant through the water heater as well as through dash heater core. It is called a motor-aid water heater and will get water in water heater up to full operating temperature-- no propane or electricity needed if you have been driving.
When valve closed, all engine produced hot coolant in that line goes to the dash heater core.
Brett
That looks like a Water Pump Accumulator Tank, except it does not appear to have a schrader valve or rubber bladder. Here is a link to a pic of one at PPL: (https://www.foreforums.com/imagecache.php?image=http%3A%2F%2Fwww.pplmotorhomes.com%2Fcat%2F868%2F250%2F868139.jpg&hash=3632e932b32d028fdbd7614a7d1f75d1" rel="cached" data-hash="3632e932b32d028fdbd7614a7d1f75d1" data-warn="External image, click here to view original" data-url="http://www.pplmotorhomes.com/cat/868/250/868139.jpg). Think I would send those pics to Foretravel and asking them. That only has the one tiny line going to it??? Does that top unscrew???
I guess the better question is do they actually drain to the outside themselves or do I need to open the main holding tank drain in addition to opening these lines?
Pat, I think the reason it may not have a schraeder valve is because this is what I rebuilt after the original one blew the top cap off and broke into about 10 pieces. The original probably had a valve, but I never saw it and rebuilt this before being part of this forum. Looks like I'll need to take it out and install a schraeder valve. Not sure how to prime it after that though.
But you would need a rubber bladder for the air to go into. Applaud you for trying to build it, but think you would be further ahead buying one. You can get them at most any RV shop or probably cheaper at Home Depot or Lowes. Well, the bladder? See this Can a water pressure tank be repaired if the bladder no longer holds the air (http://wiki.answers.com/Q/Can_a_water_pressure_tank_be_repaired_if_the_bladder_no_longer_holds_the_air) , but you are going to have to be adding air to it often.
Benjii, sorry I didn't reply sooner. We were at a FMCA Wisconsin Voyageurs rally in Marshfield, WI. (A rally is held somewhere every month up here. Great bunch of people)
When I open the two drain valves under the couch in our 36' GV the water drains out under the coach right behind the driver's front wheel--right onto the exhaust pipe of the generator. No, you do not have to open the main tank drain to assist the two drains under the couch. Just open all the faucets, pop open the top valve on the water heater and remove the bottom nylon plug on the water heater (15/16" wrench)
Benji, you do not need to add a shraeder valve on the setup you have. You will not be able to build and hold pressure in a tank without a bladder. The air you put into the valve will just go on through to the water lines and that pressure will be lost when a faucet is opened.
The air that is in the canister when the pump turns on will be compressed as the water enters the canister. That compressed air acts as a cushion doing the same thing as a bladder tank. A bladerless tank is just not as efficient and will probably fill up completely with water over time. When it does fill with water, it will become ineffective until you drain it. The only good a shraeder valve will do is let you purge the water out of the canister without draining the system when the canister becomes waterlogged .
As previously suggested, get a bladder type accumulator tank or a get a new pump with a bypass that does not require a tank. In the interim the one you made will work until it fills with water.