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PostPosted: Tue Oct 11, 2016 8:36 pm 
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Am I right in thinking that I can empty an lpg tank, take off the multivalve, turn the liquid take off pipe upside down, put it back together again, and I'd have a functioning refillable gas tank I could use for my campervan?

If so, what are the dangers of doing so? I'd rather hear productive answers that would help me achieve the end goal rather than the kind of thing my dad would say like "don't do it, you'll blow yourself up.
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PostPosted: Wed Oct 12, 2016 11:40 am 
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The short answer is yes you can - but keep reading!

The liquid take off pipe is long enough to reach from the valve to the bottom of the tank. On 30degree tanks you may need to make the pipe shorter (cut it down) to prevent it kinking around to where it would pick up liquid. On 0 degree toroidal tanks the valve is near the bottom of the tank, so the pipe won't be long enough to extend to the top unless you replace it with a longer pipe.

Still leaves the matter of the electronic shut-off valve preventing gas from coming out the tank unless power is connected, you may want this feature but probably don't because you should only really be using gas appliances while the vehicle is parked up, so when the engine is likely to be off and not charging the battery... the electro valve draws about an amp to keep it open (could flatten battery). If you don't want the electro valve then you can remove it's plunger and it will flow gas even without power but you lose the safety it would normally provide (shut of gas at the flick of a switch, which could be positioned in a handy location..). There should be a manual shut-off valve on the tank (probably a thumb screw or lever), if there isn't a manual valve you should use a valve that does have a manual valve instead for safety reasons - you should have some way of turning off the gas right at the tank and especially without an electro valve this manual valve should be accessible.

Don't want to sound like your dad but you can buy multivalves designed for purpose. Can buy refillable bottles designed for purpose which have same dimensions and look very similar to normal type portable gas bottles (except they have the 80% fill limiter etc), expensive though.

Besides multivalve tanks it is also possible to use 4 hole tanks - if a hole is made near the top of the liquid pick up pipe (can be done by removing the tank's outlet valve and working through the threaded hole drilling through the pickup tube). Not usually as viable as single hole tanks because 4 hole tanks for Autogas applications don't usually feature a manual shut off valve (which as said above should be fitted), so an outlet with a manual valve would need to be bought/fitted. I still have some 70L cylinder 4 hole tanks (previously used on forklifts) that do feature manual valves (the big tap probably easier to use than the little thumb screws on some multivalves), I've already modified and sold a few of these for your kind of purpose, fitted some in the front external gas lockers of caravans etc.

Most danger would come from you getting some aspect wrong, e.g. the valve must still be fitted the same way up, only with the pickup pipe upside down. The tank must of course be fitted in the correct orientation and properly fixed in place. If the tank is fitted internally then it should have all the same external ventilation considerations as when we fit Autogas tanks internally. Must have the same type of external filler. Summing already mentioned safety points up - fit tank to Autogas standards. Some regulators will output gas at a higher pressure, or even output liquid gas, if they are fed liquid gas instead of gas vapour - Most users of upright bottled gas have probably never experienced this because the outlet on gas bottles is at the very top of the bottle (so the regulator is only fed vapour even if the bottle is rocked a bit). Particularly with a toroidal design tank, if the tank is near full and vehicle parked off-level then regulator is far more likely to sometimes be fed liquid gas than with usual type bottled gas, especially if gas is turned on while you drive around. Autogas is propane in this country, can be a mixture of propane and butane in other countries - No problem if your appliances already use propane (i.e. if you use red bottled gas) but would need a different regulator / different jets in appliances if they currently use butane (blue bottles). Where would you mount the regulator (direct to tank or remote of tank)? You'll need a special adaptor / fittings but they're easily obtainable. I reckon with external tank direct or close to tank is safest location for the regulator, less pipe volume in the feed to the reg being better in case liquid gets into the reg feed (less volume = less potential liquid volume), but with internal tank needing to be externally vented the pipe connections will have to run outside the vehicle - so reg could be external or pipe could run back inside to the reg.

Simon

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PostPosted: Wed Oct 12, 2016 5:38 pm 
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Excellent! Thanks for a good reply, plenty of good info, it's confirmed my initial thoughts that a single multivalve would be better than a 4 hole tank.

I'm planning to install the tank under the floor in between the chassis rails of my Luton sprinter, I want to keep the gas out of the van to give me more room in the kitchen area, so those gasit type bottles aren't really suitable for my needs, and the purpose built tanks like you mentioned cost more than I'm willing to part with!

I was planning on finding a ~30 litre cylinder tank with a multivalve and bolting it up under the chassis, they seem to pop up on ebay for about £20 from time to time, so it's just a waiting game..

Then with the regulator I was looking to attach one of these Image to the tank with whatever 6/8/10mm fittings I'd need to do it, from the regulator I'd run a copper pipe to a 3 way manifold inside the van to run the shower, cooker, and heater.

I've always done my own gas fitting in several self build vans and never had any issues, so I'd like to say I'm competent enough to do it safely, but wanted to double check with regards to tanks, as that's a whole different ball game!

Thanks for your help ☺️


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PostPosted: Wed Oct 12, 2016 6:35 pm 
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Wouldn't say better than a 4 hole, just that a 2nd hand 4hole tank previously used to run an engine as part of an Autogas install won't have a manual valve, 2nd hand multivalve tank will have unless it's very old.

I was actually referring to GasIt type tanks and similar. Nick at FES used to sell Autogas equipment before moving more into that kind of stuff, other suppliers like TinleyTech also sell pretty much the same.

Looks like I wont be selling you one of these 4 holes with manual valve though, 70L capacity and probably too wide diameter to fit :( :lol:

You're welcome.

Simon

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PostPosted: Wed Oct 12, 2016 7:45 pm 
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I was more concerned about the outlet valve of a 4 hole being more of a pain to convert to vapour than a multivalve. I've not seen a 4 hole outlet valve in person so no idea if it would be possible to do something similar like turning the uptake pipe upside down in a multivalve, I assumed that the outlet of a 4 hole was more of a direct draw than the uptake pipe used in a multivalve. From the photos I've found online, they look like they just screw into the tank and draw liquid direct, like this
Image
, but you think you can add a vapour take off pipe to one of these valves?
The manual shutoff isn't much of an issue as I can easily make my own between the tank and regulator with an inline tap, and I'll also have a shutoff before the manifold inside the van.

70l is a bit too much for my needs, I don't think it would even fit without resting on the propshaft or the brake cable!
30 litres would be a good balance between weight and capacity I think, maybe I will keep a 3.9kg bottle as backup incase I get caught out one night.

I've just installed a dickinson newport p12000 propane heater, it uses about 1 litre every 4 or 5 hours and keeps the van toastie warm, so 30 litres would see me through a few days before needing to go on a gas mission.
Thanks
Iain


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PostPosted: Thu Oct 13, 2016 10:59 am 
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Acid_clown wrote:
but you think you can add a vapour take off pipe to one of these valves?
Yes and I explained how to do it in my first reply! With 4 hole tanks the tank itself has the pickup pipe built in, that's why my explanation says remove that valve and, working through the threaded hole (where valve screws in), drill a hole through the top end of the tank's internal pickup tube... Then instead of re-fitting the type of outlet valve that's in your pic, fit a none-electronic outlet valve that has a manual shut-off tap (and excess flow automatic shutoff valve) - like the ones used on forklift and, erm, motorhome tanks ;-)

Modding a 4 hole tank for vapour outlet is more difficult than removing a multivalve and rotating it's flexible pickup pipe.. can be a bit difficult to get the drill started on the pickup pipe because of the acute drilling angle and while drilling you've got to watch you don't damage the threads. 4 Hole threads are tapered, got to use gas tape or paste on them and they need a lot of tightening torque, which means already fitted valves can be very tight to remove indeed (tape / paste gone stiff).

I did say I thought the 70L tank would be too wide. I think you'll be aware a 70L tank would only fill to 56L, a 30L tank would only fill to 24L, they only fill to 80% to allow for expansion of the gas.. And that LPG only is only half the density of water, so 56L of gas weighs 28Kg while 24L of gas weighs 12Kg, then obviously the weight of the tanks and brackets to add.

Obvious drawback and potential issue with shut-off valve remote from tank (no shut-off valve actually on the tank valve) is that should a problem occur in the pipe between the tank and shut-off valve there is no way of shutting off the gas... Probably wouldn't find a commercial setup without a tank shut-off valve as it's considered unsafe.

Simon

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PostPosted: Thu Oct 13, 2016 1:51 pm 
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Oh right, the tank has the pickup as part of the tank rather than attached to the removable solenoid valve, that's what confused me when I was looking at those output valves. Still I'd rather not go down the drilling holes route! Good to know though.

I've found a 45l stako toroidal 630x190 multivalve tank, it will fit just perfectly, also has a manual shut off valve, so no worries of safety, and at 80% will give me 30something litres of gas. Should get my hands on it in the next couple of weeks, then I can start planning the rest of what I'll need.

I'll try to update this as I go for anyone else who might be interested in doing the same thing.


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PostPosted: Thu Oct 13, 2016 3:41 pm 
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All correct Iain ;-) Good luck with that.

Also for others reading this who might be considering doing the same as you... I do the drilling / mods if tank is bought from me :lol:

Simon

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PostPosted: Mon Oct 17, 2016 3:37 pm 
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I've converted a 4-hole tank to vapour using the brass bung/plate thing the gauge attaches to. It's quite easy coz it all gets done on the bench not at the cylinder.

You have to cut off the magnet and float mechanism from the inside face of the brass plate but that's dead easy with an angle grinder. Then I tapped the brass plate thing and screwed a 8mm fitting into it and soldered it all together for good measure. The inner side of the fitting has an 8mm copper pipe coming out bent up to go to the top of the tank and the outside of the fitting goes straight onto a manual gas tap.

After fitting it all under the floor I drilled through above the tap and fitted a rod down onto it so I can turn it on/off from inside. That was the hardest part.

Doing it this way meant I lost the gauge but I preserved the liquid pick up so I also have it as a reserve tank for the motor if my main tank runs out.


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PostPosted: Mon Oct 17, 2016 5:48 pm 
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Nice one Oldskool, though others might frown on the method a bit more than the other mods...
But not as much as they'd frown on hearing about cutting a hole in a tank and welding in a boss for a shut-off valve attached to a regulator... This leaves the gauge and liquid/autogas outlet unaffected but I couldn't advocate it, not even for someone who's done NDT on welds at power stations, even if they got a very competent pro Tig welder who's usually used to welding very high pressure pipes on power stations to do the welding.. Seen done a long time ago ;-) the installer removed the only vapour tank on an RV to make space for one of the autogas tanks, owner obviously still needed a vapour outlet but without removing the vapour tank to fit the autogas tank range wouldn't have been what he wanted.

Simon

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PostPosted: Sat Oct 29, 2016 2:39 pm 
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Righty ho,

I got my tank, and ordered what (I thought) I needed. And I'm almost ready to put it all together.

Here is the multivalve pics http://m.imgur.com/a/1fUXr, pic 1 is with the take off tube turned around and bent up, so far so good.... Then the other two photos are of the intake & the wrong fitting. Gah!

I just guessed that the intake looked about 8mm and the out looked about 6mm. So I went over to lpgshop and hunted for what looked right, I found a 6mm faro to m10 elbow, it fits the output valve perfectly, you can see it attached in the bottom photo.

The second elbow I found was an 8mm to m12 elbow http://www.lpgshop.co.uk/o8mm-to-m12-elbow-90deg-connector/, it looked a likely fit for the intake, so I took a gamble... Surprise surprise, it is the wrong size! It fits inside the hole, so whatever I need is bigger than m12. You can see it sat next to the multivalve in the bottom photo.

Any idea what size fitting I need? I can't find anything else on lpgshop that looks like it will fit.

Thanks
Iain


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PostPosted: Tue Nov 01, 2016 6:54 am 
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I contacted Tinley Tech, and they got back to me with the part I needed, an m14 to 8mm poly fitting. Annoyingly the rest of my stuff is 8mm copper compression, so I have had to also buy a length of 8mm poly pipe, and an 8mm poly to 8mm copper connector too. Costs are mounting...! It's on its way, so hopefully I can put it together this weekend...


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PostPosted: Tue Nov 01, 2016 10:25 pm 
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Acid_clown wrote:
I contacted Tinley Tech, and they got back to me with the part I needed, an m14 to 8mm poly fitting. Annoyingly the rest of my stuff is 8mm copper compression, so I have had to also buy a length of 8mm poly pipe, and an 8mm poly to 8mm copper connector too. Costs are mounting...! It's on its way, so hopefully I can put it together this weekend...


The poly pipe is a lot easier to work with though so its not all bad!


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PostPosted: Sun Nov 20, 2016 3:43 pm 
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I tested it out this weekend and all seems well, i chucked the tank in the back of my car, drove down to the filling station and put 10 litres of lpg in, took it back to my van and plumbed it in, everything works perfectly! My next issue is attaching the tank as I've put 10 litres of gas in it, it's now bloody heavy! Too heavy for me to hold up against the floor of the van while I bolt it on.
This is a photo of the tank and the brace to hold it on, the tank sits inside the hoop and then I can bolt the hoop to the metal rails underneath the box of my van
Image

A set of ramps would really help as I'm lying on my back with almost no space to move around as it is, there's no way I can hold the tank up and bolt it on by myself. Also it's been soaking wet all weekend so I'm not so willing to crawl around on the floor too much.

Being a stubborn git, I'm reluctant to ask someone to help me, so I think I've come up with a solution...
I've got loads of climbing gear which I use every now and again, I'm going to remove a floor tile from inside the van, drill a couple of holes and drop a rope down, then I can pull the tank up to where it needs to be from inside, tie it off with an abseiling stop, and get under the van, bolt it on, release the rope, and stick the floor tile down again. I'll report back with my results and a few photos when I've finished...


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PostPosted: Sun Nov 20, 2016 4:39 pm 
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A climber who's not willing to crawl around on a wet floor? :lol:

Simon

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PostPosted: Mon Nov 21, 2016 8:15 pm 
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Not in my Sunday best at least! :lol:


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PostPosted: Mon Nov 21, 2016 9:17 pm 
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Heh, put your climbing gear on then and have it fitted between blinks :lol:

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