cold.man
19-11-2011, 11:58 PM
im new to co2 and have a question?
for example a compound system
when pumping down a system you would have the wicker switch monitoring the pressure in the receiver which would control the resiliance unit to control the pressure in the HPR
if you was to pump down to pressure above the tripple point and carry out work wouldnt the LT prv blow off as this would be rated at 25 bar.
rule of thumb the co2 pressure would rise 10 bar per 1 degC of heat added this inturn would give you not very long to carry out work.
correct me if i am wrong but would you pump down to negative pressure valving off section to be worked on once pump down complete.
carry out repair pull 2 torr vac 13 torr if pump liquid system then recharge system with approx 7 bar vapour then release liquid from reciever slowly to reduce any chance of thermal shock to pipework.
some parts of the system depending on system type you can bypass ie liquid fiter drier ie procedure above would be followed 2 torr vac charge with vapour then reinstate liquid line drier.
rather than beating around the bush as i am my main question is when pumping down what pressure would you pump down too.
i would presume the liquid receiver would have vapour in the top to recharge with vapour prior to reinstating the system.
could sombody please correct me if i am wrong!!!!!!
for example a compound system
when pumping down a system you would have the wicker switch monitoring the pressure in the receiver which would control the resiliance unit to control the pressure in the HPR
if you was to pump down to pressure above the tripple point and carry out work wouldnt the LT prv blow off as this would be rated at 25 bar.
rule of thumb the co2 pressure would rise 10 bar per 1 degC of heat added this inturn would give you not very long to carry out work.
correct me if i am wrong but would you pump down to negative pressure valving off section to be worked on once pump down complete.
carry out repair pull 2 torr vac 13 torr if pump liquid system then recharge system with approx 7 bar vapour then release liquid from reciever slowly to reduce any chance of thermal shock to pipework.
some parts of the system depending on system type you can bypass ie liquid fiter drier ie procedure above would be followed 2 torr vac charge with vapour then reinstate liquid line drier.
rather than beating around the bush as i am my main question is when pumping down what pressure would you pump down too.
i would presume the liquid receiver would have vapour in the top to recharge with vapour prior to reinstating the system.
could sombody please correct me if i am wrong!!!!!!