Home LP tank pressure gauge questions

[rfuerst911sc]

Hey guys the other day I had my home propane company come and set and hook up a 250 gallon tank . It is teed into our 500 gallon tank . The 250 gallon tank will be our emergency/backup tank specifically for our home generator .

The 500 gallon tank does not have a pressure gauge on it , just the fuel level gauge . The 250 has fuel level and a pressure gauge . The gauge is all rusty and the guy didn't have a replacement on his truck .

It is a 1/4 " NPT thread and a 0-300 psi dial . Looking online it seems like gauges in that range are for water/air/oil/sprinkler systems but not propane . Is there a difference ? Can any gauge with 0-300 be used ? Is there any value to have a gauge seeing that the 500 gallon tank doesn't have one ?

The installer just said use a new gauge or a plug . He didn't have a plug either . I am not filling the tank until August so I have time on my side . Would you install a gauge or a plug ? If a plug black iron or brass ? He said the pop off blows at 250 psi .

[unclebilly]

The oil one will be fine. As long as it’s rated for hydrocarbons you are good to go.

I actually used hydraulic hose on each end of my burried copper line for my propane supply.

[rfuerst911sc]

Great thanks

[Alan A]

If they’re linked why do you need two gauges? Or is there a shutoff between?

[rfuerst911sc]

Originally Posted by Alan A

If they’re linked why do you need two gauges? Or is there a shutoff between?

Each tank has a shutoff valve . Each tank has a fuel level gauge . The smaller tank also has a pressure gauge . I am not seeing the value of the pressure gauge . I am leaning towards replacing the rusty gauge with a simple plug .

[fintstone]

I do not see the value of a pressure gauge. When they installed my 1000 gallon underground tank, they used a pressure gauge to test the new lines before they filled it (then a county code inspector verified no leaks), but afterwards removed the gauge. All I have is a level gauge which show the percentage remaining in the tank (just like the above ground tank at my other home). A rusty gauge seems like an additional failure point to me.

[RossR911sc]

A pressure gauge on a propane tank is of little value. It will only show reduced pressure if there is no liquid in the tank. at that point it is empty. Under normal conditions there is liquid and vapor - and only propane. When there is no propane being drawn from the tank the pressure will stabilize. Using a conversion chart you can use the pressure to convert pressure to temperature and you have a giant thermometer bulb.

[rfuerst911sc]

Originally Posted by RossR911sc

A pressure gauge on a propane tank is of little value. It will only show reduced pressure if there is no liquid in the tank. at that point it is empty. Under normal conditions there is liquid and vapor - and only propane. When there is no propane being drawn from the tank the pressure will stabilize. Using a conversion chart you can use the pressure to convert pressure to temperature and you have a giant thermometer bulb.

I agree the gauge has no value . I am just going to install a plug and be done .

[rfuerst911sc]

Update to close the thread . I installed a brass plug . Our propane supplier came last week to fill both tanks . He did a leak test on our new used tank and zero issues . Yeah 😁

I did learn a valuable tip from the propane guy . Some tanks will leak at the shutoff valve if it is partially open . They either have to be fully closed or fully open . Weird design but the tank I recently added is that design . I am glad I chatted with him .

[LWJ]

^^^Leaking valve as above? Yes. The valve has packing on the top and bottom of the valve. They do often need to be fully open or closed.

The rusty gauge (I know it was ditched - info only here) will most likely have a brass bourdon tube (forgive me if I goofed, I haven't been in the industry since 1996!) that won't rust.

And yes. Pressue is pretty worthless on LIQUID tanks.