Propane tanks on 5th wheel

You guys that think weight is the only way to fill the tanks, just haven't thought it through. How does the propane truck weigh their product when they fill stationary tanks? Or when propane fueled cars fillup, how do they weigh how much was dispensed?

Answer? They don't. They use a meter that measures gallons. And the bleed valve tells them when liquid has reached the top. Old school? I still by gas by the gallon.

This. What I was told by the propane service I use is that they pressure test new tanks with water and they never get all of it out so if you don't purge the first time the two liquids separate and the water can cause rust damage on the inside.

They keep a few bad examples at the pump to show customers what not to do, the other point he made is the plastic wrappers they put on the exchange bottles, he said it's a great place for condensation and then surface rust, the wrapper says to leave it on but the man says to take it off.


New tanks have to be purged correctly ONCE, then filled with propane by weight.

Old-Biscuit wrote:


Many times the propane 'cylinders' are shipped filled with compressed air.
Air and propane do not mix well inside the cylinders and must be purged with LIQUID propane 4x-5x before filling with vapor.
Just filling with vapor will not purge the air out and then you will have issues with popping inside cylinders, regulators failing, propane flow issues etc.

This makes no sense. They don't fill the tanks with vapor. They fill with liquid. The liquid boils off at low temperatures (well below freezing), so filling and emptying the liquid 4-5 times wont' do much of anything. The first time full will eliminate the vast majority of the air and when you open the valve, the liquid propane vaporizing will push the air out.

The first fill and letting the air bleed out is the purge. If you are going thru 4-5 tanks of L (liquid) PG you are doing something wrong.

Old-Biscuit wrote:

If NEW then you need to make sure that they have been properly purged before 1st fill.

If they are not filled by the dealer, how does the dealer or the purchaser check out the systems that require propane? Stove, water heater, furnace, fridge, etc?

New tanks have to be purged correctly ONCE, then filled with propane by weight.

Our propane shop will take them out, fill them and put them back in while we go inside and pay.

ford truck guy wrote:

2oldman wrote:

rhagfo wrote:
Not likely they would come filled on a new rig, unless really good dealer!!

Mine did.

Perhaps we need a poll of new 5er buyers to see what they got.

Mine came filled

I have purchased 2 fifth wheels new, each from different dealers, and both came with filled propane tanks.

Hopefully during PDI you would find out if full or empty.
I always test my furnace and hot water heater on propane during PDI.

Been too long, I don't recall if they were filled. But they did have propane. They could not have tested the appliances if they didn't at least partially fill. Seems unlikely that they would fill partially, leaving partial air.

I don't buy the fill/purge 4-5 times thing. I've initialized more than a few BBQ tanks, and never did anything other than schlep them down to the station and get them filled. Never had any issues. I think the liquid expelled from the bleed valve proves the air has been expelled. The air would be above the liquid.

2oldman wrote:

rhagfo wrote:
Not likely they would come filled on a new rig, unless really good dealer!!

Mine did.

Perhaps we need a poll of new 5er buyers to see what they got.

Mine came filled

rhagfo wrote:
Not likely they would come filled on a new rig, unless really good dealer!!

Mine did.

Perhaps we need a poll of new 5er buyers to see what they got.

2oldman wrote:

Old-Biscuit wrote:
If NEW then you need to make sure that they have been properly purged before 1st fill.

If new I would think they'd come already filled.

Not likely they would come filled on a new rig, unless really good dealer!!
New tanks now come Vacuum purged ready to be filled.