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CentralCoastCam's avatar
CentralCoastCam
Explorer
Jul 30, 2013

Adding an LPG sending unit

I'm in the middle of installing an iSeries tank monitoring system. This system has the ability to monitor 4 LPG tanks/cylinders as well as the holding tanks. This got me to thinking that it would be nice to have the ability to monitor the LPG tanks in my fiver. So, I did a search online and discovered that Manchester does make a 30# cylinder with a gauge (SKU 1166TC.2) I emailed Manchester inquiring if the gauge on this tank was campatible with replacing it with one with a 90 ohm sending unit. Here is the response "The dial on the 1166TC.2 is not a 90 ohm sending unit. The sending unit may work with the 1166TC.2." That wasn't very definitive.

So, does anyone know if you can put a 90 ohm sending unit gauge on one of these cylinders, or other solutions to be able to add a sending unit to a 30# cylinder?

p.s. I tried to link the iSeries monitor, Manchester web page and one that has the replacement gauges, but I couldn't get it to work using an iPad. Here are the links:
https://tankedge.com/products.html
http://www.mantank.com/products/rvproducts.htm
http://www.bluelpg.com.au/tmcart/index.php?cPath=42&sid=9f80610248eda09dd67c0b07990e0ad0
  • Francesca_Knowl's avatar
    Francesca_Knowl
    Explorer
    Jul 30, 2013
    Can't help with the sending question, but hope you don't mind if I ask one of my own:

    How do the gauges you're talking about work? Are they float-type? I ask because I thought that the only way to measure propane was by weight but was recently told that floats like those in gas tanks can be used, too.

    I did look at the tank you named but didn't see any info per the gauges there...

    Thanks!
  • CentralCoastCam's avatar
    CentralCoastCam
    Explorer
    Jul 30, 2013
    I'm by no means an expert on LPG cylinders/gauges. Just self educated when researching the above question. My understanding is they are float. You might want to take a look at this web page
    http://www.docstoc.com/docs/80508937/LEVEL-INDICATORS

    Hope this helps.
  • dougrainer's avatar
    dougrainer
    Nomad
    Jul 31, 2013
    I have NEVER seen any float system on a DOT vertical portable tank be accurate at all. The design of the vertical DOT tanks make having a good calibrated float work correctly almost impossible. Of course, I only have about 34 years as a RV tech and am licensed by the State of Texas for LP fill and repair. The only float system I have seen on DOT tanks that work well are the type tanks that are designed to be mounted Horizontally (Lay down sideways, not upright like most DOT tanks). That allows the float to actually move up and down accurately for the actual liquid level. These type tanks were popular on the older Argosy Trailers and older Airstream trailers. They even had the wired sending unit to go to the remote panel. Doug
  • ktmrfs's avatar
    ktmrfs
    Explorer II
    Jul 31, 2013
    there are two types of gauges I know of for propane tanks. both use a float, however operation is considerably different

    In once case the float moves agains a variable resistance element of some sort commonly 90 ohms total. connects to a sensor that in one form or another has the resistance reading converted to level.

    the newer one is again a float, however, instead of a resistance element, it has a magnet that moves up and down. On the outside of the tank is a gauge with a iron or other metal sensitive to the magnetic field that moves the needle. Works since the valve is brass and doesn't affect the magnetic field to any great degree.

    this is the type I've seen on many of the 20 and 30lb manchester tanks being sold.

    I've had several of the above type and they do work pretty well, but won't interface to the meter you are talking about.
  • chainegang's avatar
    chainegang
    Explorer
    Jul 31, 2013
    To original poster (CentralCoastCampers ). How did you make out with your Fresh water tank sensor screws??
  • CentralCoastCam's avatar
    CentralCoastCam
    Explorer
    Jul 31, 2013
    chainegang wrote:
    To original poster (CentralCoastCampers ). How did you make out with your Fresh water tank sensor screws??


    I gave up on trying to re-use/remove the corroded ones. That's the main reason I'm switching to the iSeries tank monitoring system (that and the DW is always bugging me about how much water we have left when boon docking).

    Dougrainer and ktmrfs,
    Thanks for info on trying to monitor the 30# cylinders. I knew there was probably a reason more people weren't doing it.
  • pkunk's avatar
    pkunk
    Explorer
    Jul 31, 2013
    I'm with Doug. I have one of the old 30# bottles w/ gage and it must be installed in a certain horizontal position for the gage to work. The bracket welded to the tank determines that position. A magnetic sending unit would work on it.
  • chainegang's avatar
    chainegang
    Explorer
    Jul 31, 2013
    CentralCoastCampers...Thanks for responding to the request on Fresh water tank sensor screws. It's distressing for one o take the time to respond to a request and not have the original poster update the solution at a later date.

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