Propane Tank Changeout

[dandick66]

I am thinking of changing out my 39 gal original equipment propane tank to a standard 5 gallon “grill type” tank.  I have an Aquahot and convection microwave, so the only propane equipment I have is the  2 burner cooktop.   I guess Monaco just used the same propane tank regardless of what equipment you have.  I will use the space for extra storage.

 I have done some calculations and here’s what I’ve come up with.  The 39 gallon tank can only hold 31.2 gallons of propane.  At 4.11 lbs/gal, the full tank (which it current is) of propane will weigh about 128 lb (propane only).  I can’t find any specs on the tank (Manchester brand), but I figure an empty 5 gallon tank weighs about 20 lbs.  I am deducing that the empty 39 gal tank should weight about 160 lbs.  The total weight will be somewhere around 290 lbs.  I will get a couple of guys to help me get the tank out.  I’ll try to sell it.  If I can’t get a decent price, I’ll put it on the porch and connect it to the grill - it should last a long time.  

I’m wondering if anyone has done this conversion. Are my weight calculations correct?  Lastly, do I need the regulator in the attached photo?  Any thoughts or comments are welcome. 
 

Dan D                  
2012 Diplomat

[ncsteve]

That seems like a lot of work for virtually no gain. Let it run down and only add what you want to put in it when needed. Not sure the thinking on fill it and don’t worry about it for a year vs having to deal with a small tank. My 2 cents

[10Boomer]

7 minutes ago, dandick66 said:

I am thinking of changing out my 39 gal original equipment propane tank to a standard 5 gallon “grill type” tank.  I have an Aquahot and convection microwave, so the only propane equipment I have is the  2 burner cooktop.   I guess Monaco just used the same propane tank regardless of what equipment you have.  I will use the space for extra storage.

 I have done some calculations and here’s what I’ve come up with.  The 39 gallon tank can only hold 31.2 gallons of propane.  At 4.11 lbs/gal, the full tank (which it current is) of propane will weigh about 128 lb (propane only).  I can’t find any specs on the tank (Manchester brand), but I figure an empty 5 gallon tank weighs about 20 lbs.  I am deducing that the empty 39 gal tank should weight about 160 lbs.  The total weight will be somewhere around 290 lbs.  I will get a couple of guys to help me get the tank out.  I’ll try to sell it.  If I can’t get a decent price, I’ll put it on the porch and connect it to the grill - it should last a long time.  

I’m wondering if anyone has done this conversion. Are my weight calculations correct?  Lastly, do I need the regulator in the attached photo?  Any thoughts or comments are welcome. 
 

Dan D                  
2012 Diplomat

Looking to do same. Mines mounted length wise in bay. 

[Dr4Film]

I have the 38 gallon LPG tank next to my fuel tank and it is nearly full. However, there is nothing left in my coach that uses propane. Someone replaced the NotSoCold with a Samsung RF-197 and the 2 burner cooktop has been replaced with a Tru-Induction cooktop. The coach has an Aqua-Hot so no propane heater either.

However, it will stay as I don't need more storage plus someday I may install a passenger side LPG hookup attachment in order to use devices like a grill or griddle or even a LPG campfire where burning wood is prohibited.

[Jim Pratten]

We’d like that space for storage  also. It’s on our project list but probably won’t get to this year. I’ll get all sorts of points from the front office when we get to take our screen room with us in the vacated space.

With stove top burners the only load, and then only when dry camping, our 45 gal tank is also a bit of overkill. A couple 20 lb tanks with switch over valve would do nicely and is the route we’ll likely go.  

Good luck with your conversion. 

[Jeff H]

One thing to consider is the bay has to remain open to the outside in case of a leak so anything stored in the area would be exposed to road grime.  Unless you put a door on the opposite side and closed in the new space.

[MyronTruex]

I lke the idea. That would give you a full pass through storage for things like a stinky slinky stored inside a piece of PVC. 

Removing the portable tank and connecting when needed would be easy.

The only draw back is the two furnaces use propane. Granted, we only fill our propane tank about every three years because we have never used the propane stove and have a convection oven. Two actually. Well three. 

 

[Tom Whitlow]

Maybe put in an electric or induction cooktop and eliminate the tank?  My coach has no propane tank.  And - I don't miss it.

[dandick66]

2 hours ago, Jeff H said:

One thing to consider is the bay has to remain open to the outside in case of a leak so anything stored in the area would be exposed to road grime.  Unless you put a door on the opposite side and closed in the new space.

I don’t have a problem with the bay being exposed to road grime, etc.  I plan on storing items I hope I’ll never need (Spare air bags, etc) in plastic storage containers.  I can’t enclose the compartment and put a door on the other side because that’s where the Aquahot is installed.

2 hours ago, myrontruex said:

I lke the idea. That would give you a full pass through storage for things like a stinky slinky stored inside a piece of PVC. 

Removing the portable tank and connecting when needed would be easy.

The only draw back is the two furnaces use propane. Granted, we only fill our propane tank about every three years because we have never used the propane stove and have a convection oven. Two actually. Well three. 

 

 I won’t have full pass through because the Aquahot is installed on the other side.  The only propane equipment I have is a 2 burner cooktop inside.  I do have an external propane connection that I’ve never used, but could connect a grill or something else.  The portable tank will be easy to refill and I can carry a spare if I think I’ll need it.

No one has addressed whether I can remove the regulator.  I guess it reduces the pressures going to the cooktop, but if I connect a grill, they have their own regulator.  Can it work with 2 regulators?

 

[Tom Cherry]

5 hours ago, dandick66 said:

I don’t have a problem with the bay being exposed to road grime, etc.  I plan on storing items I hope I’ll never need (Spare air bags, etc) in plastic storage containers.  I can’t enclose the compartment and put a door on the other side because that’s where the Aquahot is installed.

 I won’t have full pass through because the Aquahot is installed on the other side.  The only propane equipment I have is a 2 burner cooktop inside.  I do have an external propane connection that I’ve never used, but could connect a grill or something else.  The portable tank will be easy to refill and I can carry a spare if I think I’ll need it.

No one has addressed whether I can remove the regulator.  I guess it reduces the pressures going to the cooktop, but if I connect a grill, they have their own regulator.  Can it work with 2 regulators?

 

Make sure you understand the system.  UNLESS yours is different.....and most of the Monaco's had "Marshall Tanks", you have a large and HEAVY tank.  It comes with a special gauge that sends a signal to your LP monitor. The tank has a 2 stage regulator.  There is only one size...as it was easier to have one standard tank in stock so that it would fit on a Diplomat (Propane Furnace) or a Dynasty (or Camelot) with AquaHot. When you disconnect the line from the end of the Regulator, that is it.  You WOULD not retain the regulator....unless you were going to use it again. There is (most likely) a "fitting with a valve" on it somewhere down stream and to the right, in my case. That valve is there so that if you have a grill or other device (fire Pit) that takes REGULATED (not tank pressure), then you can use a quick disconnect and use your bulk tank for the source.

If you remove the tank, you could actually get rid of the rubber hose and plug it off and then use a quick disconnect (with the MALE on the MH side and use a regulated 20 pound cylinder and use it for your cook top.  I THINK that the regulator would be sufficiently sized. OR, you remove the left hand thread POL on the existing regulator and install it on a old style (most tanks are ACME today) tank and then you feed your cooktop from the 20 pound cylinder.  Both the Marshall tank and a 20 Pound cylinder have the same pressure and the existing regulator (on a POL tank) will work.

You do NOT need two regulators nor would you take regulated tank low pressures (less than 0.5 PSI) and feed it into another regulator.  Hope this make is a little clearer.  I have often wondered about pulling mine and carrying a spare 20 pound tank. However....the tank must be fully bolted or held in place, like on the front of the Travel Trailer tongue.  I DO worry about having the Tank stored inside a sealed bay....and that, in my opinion, both common sense and professional, is a NO NO!  With a TT, it is external. BUT, if you had a PU truck and put in the bed.  THE other choice would be smaller one pound cylinders and an adapter to get it to a "Regulated" pressure. But, they would quickly be depleted....

I don't need the space and the ONLY other use would be an additional set of batteries.  From a common sense, as well as NFPA code, one would NOT have a propane tank bolted to the sidewall in the former propane tank area, now with a floor (SEALED) and then have batteries that were being charged constantly in the same bay.  The batteries would require a floor....from water and road grime.   Thus, the bay would be enclosed and not vented like the existing propane tank (no floor and propane is heavier than air).  A potentially deadly combination.  So, if you converted the area into a storage container and put in a floor and such, then there would have (by code and common sense) a vented or open to the bottom side compartment for the propane tank...and I would probably put in a propane alarm in there...at the top....with a remote alarm buzzer or horn.  I guess the old safety Director and also doing fire prevention inspections and see damage from stupidity or lack of planning is kicking in.

Just be aware of how the area is designed and if you remove the tank...be sure your know WHERE or how you are going to safely store the propane tank.  A rear shelf or covered (open grating on the bottom) shelf on the rear (opposite the ladder) would be my best recommendation.  The other would be for an adapter to be made to mount the the tank on the ladder.  That weight should be OK on the ladder frame....folks carry ladders and grills and bikes on them now...usually with no incidents...

Just be aware of HOW you will convert and utilize the storage space and how you will safety have a propane tank to provide fuel for the cook top...One enterprising individual installed an electric cook top....but did it per NEC code....and it utilized several of the AC circuits...so they could cook and not run at least one AC....

[dandick66]

17 hours ago, Tom Cherry said:

Make sure you understand the system.  UNLESS yours is different.....and most of the Monaco's had "Marshall Tanks", you have a large and HEAVY tank.  It comes with a special gauge that sends a signal to your LP monitor. The tank has a 2 stage regulator.  There is only one size...as it was easier to have one standard tank in stock so that it would fit on a Diplomat (Propane Furnace) or a Dynasty (or Camelot) with AquaHot. When you disconnect the line from the end of the Regulator, that is it.  You WOULD not retain the regulator....unless you were going to use it again. There is (most likely) a "fitting with a valve" on it somewhere down stream and to the right, in my case. That valve is there so that if you have a grill or other device (fire Pit) that takes REGULATED (not tank pressure), then you can use a quick disconnect and use your bulk tank for the source.

If you remove the tank, you could actually get rid of the rubber hose and plug it off and then use a quick disconnect (with the MALE on the MH side and use a regulated 20 pound cylinder and use it for your cook top.  I THINK that the regulator would be sufficiently sized. OR, you remove the left hand thread POL on the existing regulator and install it on a old style (most tanks are ACME today) tank and then you feed your cooktop from the 20 pound cylinder.  Both the Marshall tank and a 20 Pound cylinder have the same pressure and the existing regulator (on a POL tank) will work.

You do NOT need two regulators nor would you take regulated tank low pressures (less than 0.5 PSI) and feed it into another regulator.  Hope this make is a little clearer.  I have often wondered about pulling mine and carrying a spare 20 pound tank. However....the tank must be fully bolted or held in place, like on the front of the Travel Trailer tongue.  I DO worry about having the Tank stored inside a sealed bay....and that, in my opinion, both common sense and professional, is a NO NO!  With a TT, it is external. BUT, if you had a PU truck and put in the bed.  THE other choice would be smaller one pound cylinders and an adapter to get it to a "Regulated" pressure. But, they would quickly be depleted....

I don't need the space and the ONLY other use would be an additional set of batteries.  From a common sense, as well as NFPA code, one would NOT have a propane tank bolted to the sidewall in the former propane tank area, now with a floor (SEALED) and then have batteries that were being charged constantly in the same bay.  The batteries would require a floor....from water and road grime.   Thus, the bay would be enclosed and not vented like the existing propane tank (no floor and propane is heavier than air).  A potentially deadly combination.  So, if you converted the area into a storage container and put in a floor and such, then there would have (by code and common sense) a vented or open to the bottom side compartment for the propane tank...and I would probably put in a propane alarm in there...at the top....with a remote alarm buzzer or horn.  I guess the old safety Director and also doing fire prevention inspections and see damage from stupidity or lack of planning is kicking in.

Just be aware of how the area is designed and if you remove the tank...be sure your know WHERE or how you are going to safely store the propane tank.  A rear shelf or covered (open grating on the bottom) shelf on the rear (opposite the ladder) would be my best recommendation.  The other would be for an adapter to be made to mount the the tank on the ladder.  That weight should be OK on the ladder frame....folks carry ladders and grills and bikes on them now...usually with no incidents...

Just be aware of HOW you will convert and utilize the storage space and how you will safety have a propane tank to provide fuel for the cook top...One enterprising individual installed an electric cook top....but did it per NEC code....and it utilized several of the AC circuits...so they could cook and not run at least one AC....

Tom,

Thanks for the detailed information.  I looked at the tank and it has Manchester labels on it.  I have attached another photo and as you can see, the compartment is pretty much open to the environment, so I don’t think there will be any ventilation issues.

If I decide to remove the tank, my plan is to get some plastic storage containers and put my spare air bags and any other items that I’ve been carrying “just in case”.  I would mount and secure the 5 gallon tank vertically on the door side of this compartment.  I realize I’d have to disconnect and remove the tank if I ever needed to access the stuff stored in the compartment.  The compartment is 5 feet deep before it hits the back wall of the Aquahot compartment on the passenger side.  The door is 16 inches wide, but the compartment is actually 22 inches wide.  
 

[Tom Cherry]

59 minutes ago, dandick66 said:

Tom,

Thanks for the detailed information.  I looked at the tank and it has Manchester labels on it.  I have attached another photo and as you can see, the compartment is pretty much open to the environment, so I don’t think there will be any ventilation issues.

If I decide to remove the tank, my plan is to get some plastic storage containers and put my spare air bags and any other items that I’ve been carrying “just in case”.  I would mount and secure the 5 gallon tank vertically on the door side of this compartment.  I realize I’d have to disconnect and remove the tank if I ever needed to access the stuff stored in the compartment.  The compartment is 5 feet deep before it hits the back wall of the Aquahot compartment on the passenger side.  The door is 16 inches wide, but the compartment is actually 22 inches wide.  
 

Pictures are great.  My remarks were on a tank mounted front to rear…not side to side. Your plan sounds simple to me.  The only caveat that I must include….I do NOT know for certain, but highly suspect, that there may be some FMVSS or Fed DOT specs for the current tank, that may not be incorporated into a “residential” grill tank.  I am NOT being a worry wart, just was a Safety Director and had to deal many and varied regulations.

Manchester will tell you the difference between the large tank and the small 20 lb cylinder.  There is, for example, an “excess” flow safety valve inside my tank and I know, based on a very smart member’s comments, that his 2000 Dynasty tank has one.  We both installed QD pressure lines to supply a grill and he got his in a funk and the excess flow valve “tripped” and it took a few cycles to get it unstuck.  So, I would want a cylinder that had that protection in the unlikely  event of a crash.  I don’t know about the steel and pressure, but yes…they are used on TT…but they are external to the TT.

I also don’t know if Manchester makes a smaller, but meets the same FMVSS and Fed DOT, specs.  

SO….that is my concern.  We try to make sure that our comments….as well as comments of the posters….are not something that will put folks at risk.  Therefore, I advise to check out the regs and the safety concerns….and that mounting a tank, on the rear or ladder, and installing it when needed or running an approved hose (maybe a hose in hose) line to it might be safer.

EDIT…..  @dandick66     suggest you follow this link.  Call Manchester and tell them what you want to do and let them advise.  They list a DOT and RV approved line of “tanks”.  They are helpful ….better informed than sorry…

https://www.mantank.com/products/dot-propane-cylinders-2/

FWIW.  Your existing regulator and the downstream plumbing will work if you attach the left handed POL to a proper smaller tank.

 

[dandick66]

31 minutes ago, Tom Cherry said:

Pictures are great.  My remarks were on a tank mounted front to rear…not side to side. Your plan sounds simple to me.  The only caveat that I must include….I do NOT know for certain, but highly suspect, that there may be some FMVSS or Fed DOT specs for the current tank, that may not be incorporated into a “residential” grill tank.  I am NOT being a worry wart, just was a Safety Director and had to deal many and varied regulations.

Manchester will tell you the difference between the large tank and the small 20 lb cylinder.  There is, for example, an “excess” flow safety valve inside my tank and I know, based on a very smart member’s comments, that his 2000 Dynasty tank has one.  We both installed QD pressure lines to supply a grill and he got his in a funk and the excess flow valve “tripped” and it took a few cycles to get it unstuck.  So, I would want a cylinder that had that protection in the unlikely  event of a crash.  I don’t know about the steel and pressure, but yes…they are used on TT…but they are external to the TT.

I also don’t know if Manchester makes a smaller, but meets the same FMVSS and Fed DOT, specs.  

SO….that is my concern.  We try to make sure that our comments….as well as comments of the posters….are not something that will put folks at risk.  Therefore, I advise to check out the regs and the safety concerns….and that mounting a tank, on the rear or ladder, and installing it when needed or running an approved hose (maybe a hose in hose) line to it might be safer.

EDIT…..  @dandick66     suggest you follow this link.  Call Manchester and tell them what you want to do and let them advise.  They list a DOT and RV approved line of “tanks”.  They are helpful ….better informed than sorry…

https://www.mantank.com/products/dot-propane-cylinders-2/

FWIW.  Your existing regulator and the downstream plumbing will work if you attach the left handed POL to a proper smaller tank.

 

Tom,

Thanks for the info.  Understand the safety and DOT concerns.  I live near 2 tunnels that go under rivers here in Virginia and you must stop and tell them your propane valves are turned off.  Depending on the operator they will either let you give a thumbs up, or they make you get out and they verify your valve is off and write down your plate number.  Here is a C&P from the Baltimore Tunnel.  Makes no sense to me.  You can transport 100 pounds if it’s in 10 containers, but you can’t transport 11 pounds in 1 container.  
Vehicles carrying bottled propane gas in excess of 10 pounds per container (maximum of 10 containers), bulk gasoline, explosives, significant amounts of radioactive materials, and other hazardous materials are prohibited from using both the Fort McHenry and Baltimore Harbor Tunnels. 

[96 EVO]

On 4/21/2023 at 2:26 PM, Dr4Film said:

 

However, it will stay as I don't need more storage plus someday I may install a passenger side LPG hookup attachment in order to use devices like a grill or griddle or even a LPG campfire where burning wood is prohibited.

You will be glad you kept the larger tank if you buy a propane firepit!

They can suck back propane pretty quickly!

[10Boomer]

Many of Monaco,HR and Beavers for mid - 2000s had Manchester propane tanks. They had the contract up to the end of production. You can call Manchester to special order most size tanks for your configuration, they will weld a bug in tank for the float, you can use your magnetic gauge from old tank. 

[Georgia Mike]

I have the huge tank as well and only have a two burner stove top so I converted my portable gas grill from those little throw away bottles to using the big tank. It’s so nice now I just get out my grill hook up my long LP hose that as quick connect fittings on both ends and I’m ready to grill in less than 5 min. I never worry about running out of gas now with the grill.