Puzzled on high & low pressure meter readings
03-11-2018, 10:36 AM
#1
Puzzled on high & low pressure meter readings
Just completed install of new a/c compressor, accumulator , orifice on my 1984 vette
Box store lent me vacuum pump with meters
I jump into many projects on this vette , never working on a/c and no knowledge about the meters and correct pressure readings , but still jumped into this project .
All I was told was connect everything .
Connected blue too low side at the accumulator
Connected red too high side tube
Opened all *****
Red needle never moved off zero.
Thinking bad connection ? took off and put back number of times Nothing , needle never moved off zero psi
No Freon in unit will that effect high side meter reading . Purpose of this was too drain moisture .
After an hour, Blue side meter dropped into green 30 .
Shut off vacuum pump and low side held psi green 30 and stayed that way hours.
Thinking too myself I did a good job held psi .
Left hoses & meter connected too fittings all night.
Got dark and lost steam .
Pump was off only connections in place
In morning I wanted too make sure it held pressure all night .
Low side, meter read O , Lost pressure .
Low held psi hours with pump off but 12 hours it lost ? Is that normal
Thank you as usual
Box store lent me vacuum pump with meters
I jump into many projects on this vette , never working on a/c and no knowledge about the meters and correct pressure readings , but still jumped into this project .
All I was told was connect everything .
Connected blue too low side at the accumulator
Connected red too high side tube
Opened all *****
Red needle never moved off zero.
Thinking bad connection ? took off and put back number of times Nothing , needle never moved off zero psi
No Freon in unit will that effect high side meter reading . Purpose of this was too drain moisture .
After an hour, Blue side meter dropped into green 30 .
Shut off vacuum pump and low side held psi green 30 and stayed that way hours.
Thinking too myself I did a good job held psi .
Left hoses & meter connected too fittings all night.
Got dark and lost steam .
Pump was off only connections in place
In morning I wanted too make sure it held pressure all night .
Low side, meter read O , Lost pressure .
Low held psi hours with pump off but 12 hours it lost ? Is that normal
Thank you as usual
03-11-2018, 08:10 PM
#2
Race Director
The vacuum pump is supposed to create a vacuum in the system and not pressure. Maybe that's what you are trying to say.
I don't know what kind of equipment you are using, but In order for a "vacuum test" to be valid, you have to shut off the valve between the pump and the gauge head set once you turn off the vacuum pump, if you don't, then the stopped pump will allow air back into the system. Maybe that's what happened.
I don't know what kind of equipment you are using, but In order for a "vacuum test" to be valid, you have to shut off the valve between the pump and the gauge head set once you turn off the vacuum pump, if you don't, then the stopped pump will allow air back into the system. Maybe that's what happened.
03-12-2018, 06:30 AM
#3
Mission accomplished .
Thankfully my vette has had little issues except minor repairs here & there.
Used seldom , started often , driven locally but the days of top down , loud music , cigar in hand are long gone.
Considered selling but not selling a c4 with 34 thousand miles for a few grand . Teasing granddaughter who is going on 18, what color should I paint it , Its yours at some point
Jumping into projects , most times completed fine . This forum & U TUBE is a valuable source for project help
Those of you that try too help , my babble is tough reading, Thank You .
Finished yesterday . No leaks, holding vacuum . Few cans of Freon , cold .
Issue I had was I put Teflon tape on threads , NOT correct .Leaking
Once removed everything was good . Green 30 held
Orifice tube removal was easy , able too grab with needle nose ,
Not 100 % were tube was located . Opening the hex nut was challenging . If I did this often enough I would have McDyvered some device making this easier . Getting hands and leverage was tough . But completed .
THANKS
Thankfully my vette has had little issues except minor repairs here & there.
Used seldom , started often , driven locally but the days of top down , loud music , cigar in hand are long gone.
Considered selling but not selling a c4 with 34 thousand miles for a few grand . Teasing granddaughter who is going on 18, what color should I paint it , Its yours at some point
Jumping into projects , most times completed fine . This forum & U TUBE is a valuable source for project help
Those of you that try too help , my babble is tough reading, Thank You .
Finished yesterday . No leaks, holding vacuum . Few cans of Freon , cold .
Issue I had was I put Teflon tape on threads , NOT correct .Leaking
Once removed everything was good . Green 30 held
Orifice tube removal was easy , able too grab with needle nose ,
Not 100 % were tube was located . Opening the hex nut was challenging . If I did this often enough I would have McDyvered some device making this easier . Getting hands and leverage was tough . But completed .
THANKS