propane tank switching - Montana Owners Club

genecurp · 12-06-2005, 06:27 AM

My 2006 3295RK has 2 propane tanks, each 30 pounds, with an automatic switchover regulator. The manual says to leave only one tank open and have the valve at the top of the other tnak (reserve tank)turned to off. After depleting tank one the manual suggests I turn off tank one and turn on the reserve tank.

My question is: if I leave both tanks valves on top turned to "on", will propane be drawn first from 1 tank until empty and then begin drawing from the second? Or will pressure be equalized between the two tanks so they will both be depleted at the same time?

Part two and for extra credit: Why does the manufacturer recommend to leave a reserve tank turned off? Just to be sure you get notified when your supplies are half gone? It seems leaving one tank turned off defeats part of the convenience of having an automatic switch over (as I assume it would operate).

Thanks in advance. You folks are great.

richfaa · 12-06-2005, 06:41 AM

I am sure there is a good safety/liability reason for doing that..however in 20 years of hard side campers we have always left both tanks open.To leave one closed defeats the purpose of a auto change over???

Montana_4944 · 12-06-2005, 06:58 AM

We leave one closed just so we know one tank is gone. We also got a spare that we always keep full. Where we have problems is in the change over process it take a while for the propane to get going. We left both tanks open the first time out and ran out of propane and of course it was at 4 O'clock in the morning. It was a cold lesson!

Pete Hanson · 12-06-2005, 07:44 AM

We leave both tanks turned on to take advantage of the automatic switch-over. You need to get into the habit of checking the indicator on the valve periodically to watch for the red color which indicates that the tank you were drawing from is empty. The handle on the valve points to the tank that is being indicated by the green or red color.

ols1932 · 12-06-2005, 08:16 AM

Quote:

quote:Originally posted by Pete Hanson

We leave both tanks turned on to take advantage of the automatic switch-over. You need to get into the habit of checking the indicator on the valve periodically to watch for the red color which indicates that the tank you were drawing from is empty. The handle on the valve points to the tank that is being indicated by the green or red color.

I agree. That's what the little red indicator is for. When it shows, switch to the other tank and refill the empty one. For the life of me, I don't understand why anyone would want to only have one valve open, run out of gas in that tank at night and then have to go open the other valve AND still switch the pointer over to that tank. Brrrrr. That's why they made it automatic. I can't find anywhere in my literature that tells me to only have one valve open.

gkbutler · 12-06-2005, 08:20 AM

We leave both tanks on. I agree with everyone else, if you only open one valve, you can't take advantage of the automatic switch over

genecurp · 12-06-2005, 08:30 AM

Gee thanks. SO I understand Pete Hanson and ols1932 to be saying it does draw 1 tank down to empty before it starts drawing from the other tank. That is perfect.

Hey, I can handle checking for the red or green indicator. I have been pouring hot water on the tank to estimate the remaining fuel.

Thanks again to all.

VanMan · 12-06-2005, 09:35 AM

Those temperature activated magnetic strip indicators work pretty well for indicating the remaining level as long as you actually have propane flowing from the tank (in use)

patodonn · 12-06-2005, 09:36 AM

The only caveat I would add is to be sure the regulator valve handle is set to the tank you want to use up first, but not the center (straight up) position. Both valves on both tanks should be "ON".

In cold conditions, if the furnace is used, we check the indicator every 3 or 4 days; in warm weather, once every month. We don't use the propane function of the water heater much, only in the evenings at bath time. A lot depends on how much and what kind of cooking you do.

Roman4 · 12-06-2005, 10:30 AM

I might point out that the automatic changeover valve, while an outstanding concept, is not totally foolproof. We just had our valve replaced because it was drawing out of both tanks simultaneously. I got the impression from the service writer that this was not an unheard-of malfunction.

HamRad · 12-06-2005, 01:21 PM

genecurp,
I tried using the tanks with the lever in the middle and both tanks turned on UNTIL we ran out of fuel in the middle of the night. Now I have the lever pointed at one tank and the other tank closed. To check the level of fuel I do a "lift" and "feel" test. As soon as the primary tank starts feeling light I switch the lever and turn on the other tank. I then turn off the near empty tank and remove it from the trailer and go get it filled up.

I realize it "defeats" the purpose of the auto regulator but this system prevents or at least keeps me from running completely out of fuel. Do what works for you.

HamRad

Charlie · 12-06-2005, 01:25 PM

I agree with all those that opt to leave both valves open and have the tanks to switch automatically, this is the way the auto switching system should work and worked on all the previous trailers that I have owned.

However, I can no longer use my switching system as it was designed. I am probably the only one on the forum that has run into this problem and I only found the problem today. Since we bought the Monty in March we have used a total of four tanks of propane. The first and third were from the door side of the trailer, the second and fourth were from the TV driver's side. When the second tank was empty and tried to switch back the switching valve was stuck internally and would not work. I replaced the valve and regulator as I have reported here previously as I felt the valve was defective and everything was fine until today when the fourth tank emptied and supposed to switch again. Again the switching valve was stuck internally and would not work.

I again removed the switching valve/regulator and went to a RV store to replace it. This time I intended to use a different system if I could as I felt there must be a design fault with the one that I had. When I returned home I realized there was not a problem with the valves, but what happened during construction. On the slab under the trailer where the hose that comes from the regulator to the main header for the trailer was a spot of oil that might have been as much as a teaspoon full that had drained out of the hose.

Where the oil came from I am not sure, but my professional knowledge of propane and the stench (Mercap) that is used in propane does not have the existing properties to form oil. My suspicion is that the 3/4" pipe that crosses the trailer was not cleaned after threads were cut and what I am seeing is residual thread cutting oil that was left inside the pipe as the valve has failed the same way both times.

I redesigned the system by replacing the switching valve/regulator combination with only a regulator and installing manual operated isolation valves. This is going to be a pain as I will have to do the switching as each tank comes empty. This also will probably be a temporary fix until I can replace the cross pipe with a clean system. In the future I will remove and check the low spot for any futher accumulation of oil after the tank is emptied from the TV driver side.

Rich....there is not a PDI list out there that could foresee a problem such as this.

RADHAZJOE · 12-06-2005, 02:32 PM

OK, thats how it is supposed to work. However, when I see the red indicator and switch tanks, I close the "empty" tanks valve. Then I take out to refill. But, lo and behold, its is still half full. So I put it back in and turn on the valve.

Then some days, etc later, the red shows again for the other tank. Repeating the above gets the same results. A 30 lb tanks should weight about 24 lbs empty and 54 or so full. It seems I have to keep doing this every after 10 or so lbs out of each tank, switching back and forth until one is actually empty. Just for fun, I left and empty tank with valve on for a week and drawing from the other tank. Then I checked. Wow, it now weighed 34 lbs and had started refilling from the other tank which weighed 28 lbs. Also, about half the time, when I take the empty tanks out, propane continues to come out the hose until I ruen the other tank off.

The regulator, etc tests ok on the bench. And keystone says I don,t need a new regulator. Wow, Iam somehow either creating propane oror, who knows what.

Mac · 12-06-2005, 03:05 PM

I prefer to use one tank at a time and when it's empty switch over. Now that has meant me getting up in the middle of the night and changing the tank over because the furnace was blowing cold air, but I warmed up when switched to my full tank. The alternative would have been to freeze all night and wait until the morning to fill both tanks, I'll take the short discomfort over the long night of cold at 11,000 feet.

mac

richfaa · 12-06-2005, 03:31 PM

I have NEVER had any of these problems with the propane regulators.Of course I have never had a Montana.

OntMont · 12-06-2005, 03:47 PM

Oil in propane lines seems to be a fairly common occurance. There are threads on this on the Open Roads Forum. Some suggest that it is a residue from pressure testing the tanks, others suggest it is there as a lubricant for o-rings. I don't know why it is there, but I know that there is oil in the 20lb cylinder that I use on my gas grille at home.

As for problems with the regulator, the regulators are made by Marshall Gas Regulator Company, and they have a good customer service department. Try giving them a call.

BTW, I always leave both tanks open, and they change automaticly.

Trailer Trash 2 · 12-08-2005, 05:08 AM

The only problem I see with the switch over valve is, it was desined for travel trailers and looking down at the switch you can see the direction arrow of the tank being used, but if you forget like me you end up getting a mirror and look down at the switch. the manufacture needs to put the arrow in two places on that lever one on top and the other on the outer edge so it can be seen when in a compartment.

TT2

Glenn and Lorraine · 12-08-2005, 05:30 AM

Quote:

quote:Originally posted by Pete Hanson

We leave both tanks turned on to take advantage of the automatic switch-over. You need to get into the habit of checking the indicator on the valve periodically to watch for the red color which indicates that the tank you were drawing from is empty. The handle on the valve points to the tank that is being indicated by the green or red color.

Never done it any other way. The automatic switch-over is the only way that makes sense to me.
Besides, If the valves going to go bad it will do so no matter how you do it.

Glenn and Lorraine · 12-08-2005, 05:34 AM

Quote:

quote:Originally posted by Trailer Trash 2

The only problem I see with the switch over valve is, it was desined for travel trailers and looking down at the switch you can see the direction arrow of the tank being used, but if you forget like me you end up getting a mirror and look down at the switch. the manufacture needs to put the arrow in two places on that lever one on top and the other on the outer edge so it can be seen when in a compartment.
TT2

Not sure what you are looking at but in my Montana it is quite obvious which way the the switch is set. I open the rightside propane compartment door and the switch over valve is right there and it is always pointing at the line in use. It's the top of the valves on the tanks themselves that is difficult to see but if you keep them open while in use there is no doubt.

Charlie · 12-08-2005, 07:21 AM

Not having read threads from the other forum I can't comment on them. As far as the oil in propane, somewhere out there they may exist but I am not aware of any systems that need oil to lubricate o-rings. Motors that run on propane are lubricated the same as others with crank case oil. Small propane tanks of the size that are used in RV's and other small applications are usually tested pneumatically, proper test of a tank is a hydro-test (water), but they do not want to mess with cleaning the water out of the tank as any water left in the tank would freeze the OPD when filling with propane. In larger applications tanks are hydro-tested and usually dried with nitrogen. Other drying agents such as hot air can be used, but then the system has to be oxygen free before filling with propane. Liquid propane under pressure, about 180 PSIG, is a clear hydrocarbon that completely evaporates at -35 to -38 degrees F at atmospheric pressure. Somewhere in the process it is also passed through dehydrators to insure that it is moisture free.

It is of my opinion that if a propane system has oil in it someone has made a mistake somewhere along the line. Most likely source would be at a refinery where someone mixed a "dirty" stream with good propane and sent it to a storage tank. The oil being heavier than propane would settle to the bottom of the tank and if procedures were followed properly, the tank would be tested and drained of any such sediment before delivery avoiding shipping any bad propane to a bulk dealer and then sold to the consumer. Transfer pump suctions are usually elevated 18-24" from the bottom of a tank to avoid such incidents, however it still happens.

In my particular case I am 99.99% sure what I drained out of the hose coming from the cross pipe to the switching valve is thread cutting oil. Maybe someone that has been to the factory can say, but I don't think that Keystone would cut pipe on location. My feelings here are that Keystone contracts things like this out and would receive "X" number of pre-cut cross pipes on an order from the contractor. Regardless of who cut the pipe it should have been cleaned and inspected, could have been last job before lunch or quitting time and it got dropped in a crack and I was the unlucky one to have it installed in my trailer.

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