what is the reading in the gauge if co2 cylinder newly refilled?

**wllm33** · 24th Jul 2009, 00:37

hi guys,
just got my aluminium co2 cylinder filled today. Think it is a 1.5L.
brand new refilled but not sure if this is supposed to be full.
the gauge attached, when it was supposed to be fully refilled, it sort of read about 60 kg/cm3.

my manual gauge has a range of up to 150, where the red range is between 100-150, but the needle is at 60. Is this supposed to be correct even after it is back to normal temperature?
First time refilling so a newbie at this.
thanks for your advice.
cheers.

**tawauboy** · 24th Jul 2009, 08:07

the pressure gauge only tells you the co2 vapour pressure. as long as there is liquid co2 in your cylinder, the pressure will remain ~1000psi. this pressure will change according to ambient temperature.

the other gauge is showing your working pressure. again it will remain stable until you have used up your co2. the regulator is supposed to regulated the output pressure.

to determine whether your cylinder is full, you'll need to weigh your cylinder when it is empty and when it is full. since your cylinder is 1.5l, the difference in weight should be about 1.5kg.

**wllm33** · 25th Jul 2009, 00:42

i only have one gauge connected (newbie).
when i refill, the needle was pointing very close to 0, so i guess it will be no more co2 left soon. Guess this was just showing the pressure of the co2 was low then.

unfortunately i did not weight it before i refilled. Maybe next time i will do it cos too late now.
will try to weigh it full now and see if got 1.5kg. Actually not too sure what is the exact volume of this cylinder cos bought from someone here and he also doesn't know what is the volume either.

**Wabi-Sabi** · 25th Jul 2009, 12:30

How long have you been using the refilled cylinder before it reaches 0? Did you open the cylinder top knob fully? For a 5L, it will take about 3 to 6 months before it reaches 0 depending on the rate you pump co2 into the tank. For 1.5L cylinder, I guess one or two months.

By the way, invest on a solenoid as those manual regulators normally give inconsistent readings.

**tawauboy** · 25th Jul 2009, 14:04

a solenoid does not help in regulating pressure.
it is part of an electrical on/off valve.
for proper co2 setup, you'll need a co2 regulator. usually they have 2 gauges, one for cylinder pressure and the other for working/output pressure.
a needle valve is needed for controlling co2 flow rate.

**wllm33** · 27th Jul 2009, 00:02

Originally Posted by tawauboy

a solenoid does not help in regulating pressure.
it is part of an electrical on/off valve.
for proper co2 setup, you'll need a co2 regulator. usually they have 2 gauges, one for cylinder pressure and the other for working/output pressure.
a needle valve is needed for controlling co2 flow rate.

my single gauge gives me the cylinder pressure.
there is a knob on the side which i can turn to control the co2 flow rate, but it is manual so not very precise. But i have a bubble counter to give me an idea of the bps rate.
it is the cylinder pressure which i am concern about. Why 60, and not 100 when fully refilled?
Just don't want to be short changed , that's all.
thanks.

**tawauboy** · 28th Jul 2009, 07:24

Originally Posted by wllm33

......
it is the cylinder pressure which i am concern about. Why 60, and not 100 when fully refilled?
.....

you are looking at pressure, not how full your cylinder is.
as mentioned before, cylinder pressure will remain constant until all liquid co2 has been boiled off. so, as long as the pressure in ~1000 psi, you'll know that there is liquid co2 in your cylinder but not how much.

**wllm33** · 28th Jul 2009, 23:37

hopefully the shop which filled the cylinder will know how much co2 is being put in assuming they have the equipment to monitor it, or it is just an estimate at best.
guess got to put some trust in this refilling thing. Very hard to do this "trust" thing nowadays if you know what I mean.
just my personal opinion, no malice intended.

**greenaqua** · 3rd Aug 2009, 18:08

I think a standard gauge is 1000 psi when full. I noticed everytime I get my 1.5l tank back from Clementi its at 1000 psi. It stays there for 1-2 months until depleted when the needle quickly falls to zero. The moment it moves away from 1000 psi after 1-2 months it seems that it falls to zero in a matter of days.

**Shadow** · 3rd Aug 2009, 18:13

Originally Posted by wllm33

hopefully the shop which filled the cylinder will know how much co2 is being put in assuming they have the equipment to monitor it, or it is just an estimate at best.

usually they do this by weight, you can try weight before and after the next time go for top up.

**Shadow** · 3rd Aug 2009, 18:14

Originally Posted by greenaqua

The moment it moves away from 1000 psi after 1-2 months it seems that it falls to zero in a matter of days.

It is because no more liquid CO2 to maintain 1000psi pressure.

**wllm33** · 3rd Aug 2009, 23:35

Originally Posted by greenaqua

I think a standard gauge is 1000 psi when full. I noticed everytime I get my 1.5l tank back from Clementi its at 1000 psi. It stays there for 1-2 months until depleted when the needle quickly falls to zero. The moment it moves away from 1000 psi after 1-2 months it seems that it falls to zero in a matter of days.

just a noobie question :
full means up to just before the red part of the gauge or full till the max of the gauge?
mine is also 1.5l so should be same as your reading . Just want to compare if mine is also pointed at the same spot since I didn't weigh it . Seems like the gauge still has a lot of mileage to go even when just top up if the gauge is correct. But since it doesn't tell the capacity so not really sure what the arrow means.
blur

**tawauboy** · 4th Aug 2009, 07:46

the gauge is used to show gaseous co2 pressure. as long as there is liquid co2, the needle will stay around 1000psi, depending on the surrounding pressure. this pressure reading is independent of co2 cylinder size; it will show the same reading for 1 litre, 5 litre, 100litre, ...

the gauge does not show how full your co2 cylinder is.