View Full Version : Checking for leaks during charging or vacuum
If i were to leave a system with the manifold gauge connecting the high side and low side after charging or vacuum. And a few minutes later the pressure drops by a little.
Does it mean i have a leak in the system?
Or does the refrigerant leak out through the yellow hose which is not connected to anything.
Or the manifold connections are not secure and it leaks out from there.
If there is no leak does it mean that even with the hose connected, the pressure would stay there even till the next morning without ever dropping or otherwise.
I could not find a better way to do leak test and detergent and soap dont really work that well for small holes.
jinu117
10-31-2005, 08:19 AM
Low permeating hose is what most gauge hose are. It will slowly "leak" but very slowly. Chances of actual leak would be more on manifold connections to schraeder, etc. And if you are talking few minutes, it sounds to me more like leak on system than manifold. Have you pressure tested your manifold? separate and conquer is the name of game on leak finding.
hmmm i wonder if it is my flare joints. i have tighten them wuite tightly so tight that i could not even turn them any more.... :D
jinu117
10-31-2005, 08:23 AM
Flare joint? What did you flare joint?
Txv and filter drier. I place the plumbing tape with oil before i join it..That is what some of them suggest to me when using flare joints.
jinu117
10-31-2005, 08:39 AM
Tape? Dunno if that's good idea...
RussC
10-31-2005, 01:34 PM
Overtighten'd flare joints are a suspect? Stewie was talking to this just a week back. You may have to redo those.
RussC
hmmm i wonder if it is my flare joints. i have tighten them wuite tightly so tight that i could not even turn them any more.... :D
wdrzal
10-31-2005, 01:54 PM
changes in ambiant temperature will cause pressure changes also.
boshuter
10-31-2005, 02:57 PM
If the pressure/vacuum only dropped a little then stayed steady for a long time you may not have a leak. It may have only "settled" when you removed the vacuum pump or charge.
Tape and/or oil on a flare is not a good idea, if a flare is not sealing by itself then something is wrong with the flare joint. It's better to repair it than put a bandaid on it.. ;)
imdying
10-31-2005, 04:48 PM
As above, tape is never required on a flare joint. If anything is leaking past the flare, you've already got problems.
I dont get it Overtightening them will lead to leaks? lol then how tight is tight or dun tell me now i have to get a torque wrench to tell me it is too tight.
jinu117
10-31-2005, 04:58 PM
you don't have torque wrench? :P
Would be interesting to know how tight it really needs to be. I've done couple of flare jobs and all I did was test for the leak afterwards after what I felt was tight enough but not enough to stress tubing... Wonder what the appropirate steps are.
Yikes how the hell am i suppose to know whether have i over tighten. i tighten it using quite a lot of strength there. Ahh i hate small leaks. I heard that it may be due to oil as well as the absorb the refrigerant.
imdying
10-31-2005, 05:38 PM
You don't need to use much force. Best way is to do them up tight, without being heavy handed, then back the nut off, another half turn tight, back the nut off, another half turn. This helps the flare form to the seat.