Reply
 
Thread Tools Display Modes
Old 01-17-2014, 03:00 PM   #11
Old Enough to Know Better
 
gasman6674's Avatar
 
Join Date: Feb 2012
Location: Greenwood, In
Posts: 462
Cylinders are never 100% full by code is max is 80% so a 20# cylinder will hold 20# of gas 4.24 # per gallon or 4.71 gallons but the wc (water cap) is 47.6# or 5.95 gallons any way if you can upsize (if you have room) your cylinders to a 30# or a 40# you might eliminate the issue. I just attached a chart that I think will help you out.
Attached Files
File Type: pdf Cylinder Vaporization Rates.pdf (431.8 KB, 54 views)
__________________

__________________
Jim & Debbie England
Do you have Gas? 2015 F350 6.2L CCLB DRW 4.30 axle. 2012 Yellowstone Ridgeline 34RLT Fifth Wheel
gasman6674 is offline   Reply With Quote
Old 01-17-2014, 03:53 PM   #12
Junior Member
 
Join Date: Nov 2013
Posts: 9
Quote:
Originally Posted by gasman6674 View Post
Cylinders are never 100% full by code is max is 80% so a 20# cylinder will hold 20# of gas 4.24 # per gallon or 4.71 gallons but the wc (water cap) is 47.6# or 5.95 gallons any way if you can upsize (if you have room) your cylinders to a 30# or a 40# you might eliminate the issue. I just attached a chart that I think will help you out.
Thanks for the charts. Those are some of them that I've found on the internet and used to do my calculations. The vaporization rate chart is based on 25% full tanks. I have yet to find one for smaller tanks that shows the full range from empty to full, like they have for 100 lb tanks.

I based my calculations on 100 pounds and 20 pounds and 30 pounds, which already takes into account the 20% reduction. However, that's another variable to be mindful of. Some stations don't give you a full 20 pounds. Usually that is more important for calculating and comparing price/gallon between different stations, but in this case, where frosting is an issue, I'll want to make sure my tanks are as close to the full rating as possible, to increase my runtime before I run into problems.

The RV came with 20 lb tanks. I immediately switched them over to 30 lb tanks, just to give me a longer time in between fills. Just so happens that it will also assist a bit with the possible frosting issue.

I don't have room for 40 lb tanks in the cubby hole where the tanks sit, or I would go with 40 lb tanks. I suppose another option would be to install a couple 40 lb tanks on the tongue of the RV (if they'll fit), rigged with a regulator that uses both tanks at the same time (twice the surface area), and connect the generator to those. That way I wouldn't have to lug tanks around loosely each time I go to the fish house.

The downside to this approach is that I lose the convenience of taking a fully empty tank out and filling it while still having another tank in use. I'd also still have frosting issues when the tanks are closer to empty than full and I'd need to make sure the station is charging for what they put in rather than a flat fill rate, regardless of how much is in the tank when they start, so that I don't effectively pay twice for the left over propane in the tanks.

I just got the generator and haven't used it yet with the house being used for ice fishing. I have a suspicion that I'll be well below the max rating on the generator much of the time. So even though max is estimated to be 30,000 BTU worth of propane, I could be considerably below that. If so, then I may be just fine. There may be some frosting when the furnace kicks on at the same time the generator is running, but there may also be some amount of buffer in the tanks (gas phase propane) that will handle the demand of the furnace until it shuts off, before I run into a reduced BTU output at the tank due to cold/tank level.

I'll just have to try it when I convert the generator. Right now I'm still trying to find the parts for Teeing/Y-ing off the output of the changeover regulator. If anyone has any internet sources for parts to do this, please let me know.

Thanks again for the info.

David
__________________

__________________
x_david_x is offline   Reply With Quote
Old 01-17-2014, 04:09 PM   #13
Old Enough to Know Better
 
gasman6674's Avatar
 
Join Date: Feb 2012
Location: Greenwood, In
Posts: 462
You can get the pipe fittings at any hardware or big box store, the quick disconnect from camping world, ebay or your local lp dealer. Most charts are based on worse case. Adding tanks to your tongue is a good idea if you have room then you never have to worry about waking up frozen, You can get a RegO 7525B34 change over from your local LP dealer it will handle 400,000btu.

Good Luck
__________________
Jim & Debbie England
Do you have Gas? 2015 F350 6.2L CCLB DRW 4.30 axle. 2012 Yellowstone Ridgeline 34RLT Fifth Wheel
gasman6674 is offline   Reply With Quote
Old 01-17-2014, 05:20 PM   #14
Junior Member
 
Join Date: Nov 2013
Posts: 9
Quote:
Originally Posted by gasman6674 View Post
You can get the pipe fittings at any hardware or big box store, the quick disconnect from camping world, ebay or your local lp dealer. Most charts are based on worse case. Adding tanks to your tongue is a good idea if you have room then you never have to worry about waking up frozen, You can get a RegO 7525B34 change over from your local LP dealer it will handle 400,000btu.

Good Luck
Thanks for the info. I was hoping to find it all put together, but if I have to make it myself, I'll do that.

Well, I feel really stupid, but when I went out to take a picture of my "changeover" regulator, I realized it wasn't a changeover after all! I was *told* it was, so I just believed it. They just have the two tanks teed into the input of a regular low pressure regulator. It is that tee that I need on the other end of the regulator (what I've circled in RED in the picture below) to hook up to the main line going into the RV and to a pigtail going to my generator.

Here is what it looks like now:

Click image for larger version

Name:	regulator_close_up_edited.jpg
Views:	112
Size:	33.6 KB
ID:	45079

I have been in that cubby hole a few times and just never looked at the regulator close enough to realize that it could never function as a changeover, because both tanks are going into the same tee. That would have to be a very special tee to make it work as a changeover.

So, this means that I do have two tanks operating at the same time (if both valves are open) and twice the surface area. If I want to fully use one tank, I'll have to shut off the second tank and only open it when the furnace goes out (wake up frozen, as you said) or generator stops running, which will indicate to me that the first tank is done. If I start frosting up, then I'll have to open up both of them.

I did find a place that has all the individual fittings and I'm guessing one of the tees there will work. X106-B on this page seems like what I need:

Brass Fittings, Valves, Brass Nipples, Disposable Cylinder Adapter, Gas Orifice, Gas Manifold Parts

Here is what it looks like:


Name:   FFM_tee.jpg
Views: 177
Size:  5.3 KB

I'm hoping that is the same as the tee on the top of the regulator in the picture.

If the bottom of the regulator is 3/8" instead of 1/4", then I need X106-C on that page of adapters.

I probably won't get around to doing any of this for a while, so if anyone reads this and knows of a place that sells a pre-made quick connect pigtail on one end and a screw in connector on the other end (for the RV line), please let me know.

Thanks,
David
__________________
x_david_x is offline   Reply With Quote
Old 01-19-2014, 06:55 PM   #15
Old Enough to Know Better
 
gasman6674's Avatar
 
Join Date: Feb 2012
Location: Greenwood, In
Posts: 462
That tee on the inlet of the regulator may have a (shuttle type) check in it to keep the tanks from cross filling also the male thread on the end of the pigtail is 1/4" male inverted flare. As for a hose and quick disconnect check the Mr. Heater web site for part #'s then you can probably find online @ Amazon, Ebay Etc. PS I have never seen a regulator like that ever. I would switch to a true changeover.
__________________
Jim & Debbie England
Do you have Gas? 2015 F350 6.2L CCLB DRW 4.30 axle. 2012 Yellowstone Ridgeline 34RLT Fifth Wheel
gasman6674 is offline   Reply With Quote
Old 01-20-2014, 05:23 PM   #16
Junior Member
 
Join Date: Nov 2013
Posts: 9
Quote:
Originally Posted by gasman6674 View Post
That tee on the inlet of the regulator may have a (shuttle type) check in it to keep the tanks from cross filling also the male thread on the end of the pigtail is 1/4" male inverted flare. As for a hose and quick disconnect check the Mr. Heater web site for part #'s then you can probably find online @ Amazon, Ebay Etc. PS I have never seen a regulator like that ever. I would switch to a true changeover.
I can't be sure, but my suspicion is that the tee doesn't have anything in it to prevent propane flowing between tanks. I say this, because I had the rig out on the ice this weekend for the first time and long story short is that at one point I checked the tanks and they were both frosted to at the same level. When I put the tanks in, one had a lot more propane in it than the other one.

It is possible that the fuller of the two was used down to the level of the other one, but given the little use they've had, I'm doubting that possibility.

When you are speaking of the male thread on the end of the pigtail, do you mean going from the tank hose into the tee or do you mean the south end of the tee that is going into the regulator?

I couldn't find that regulator online, and I looked at a *lot* of pictures on the web. I did find a part number on it somewhere and I think that additional research led me to the conclusion that it is a European part. Of course, I searched online for a regulator that would allow two tanks to be used at the same time and didn't find anything. This led me to guess that everyone just uses a regular regulator and tees into it like the one I have.

I'm guessing this system was put in place due to the fact that this rig will be used on the ice (cold weather) and two tanks being used at the same time will reduce the chances for frosting. Currently, I plan to refill the tanks and then close one off and run on one tank. If using the generator and furnace at the same time frosts the one tank (either due to its fill level or outside temperature), then I'll open them both up as needed.

Without some sort of tank heater, I'll probably just have to live with not being able to completely empty a tank before refilling. I'll just need to make sure the station I choose only charges for the amount they put in, rather than a flat fee per tank.

Thanks again,
David
__________________

__________________
x_david_x is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Virginia Campgrounds

Reviews provided by




ForestRiverForums.com is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 03:21 AM.