Re: verifying a/c charge amount

["jtrealtywebspannet" <jtrealty@xxxx>]

There are 4 ways I know of to properly fill an A/C system using the 
types of expansion valves used on cars. In order of precision they are
1) Filling by weight, only good on premanufactured systems like cars 
and refigeraters and only after the system has been evacuated.
2) Using a sonic device to detect supercooled droplets in the suction 
line.
3) Filling to the sight glass (If a sight glass is even on the 
system).
4) The least precise and most widely used method, filling till the 
compressor runs or at least to a suction pressure corresponding to 
about 34 degrees F for the refrigerent being used. This can result in 
overcharging depending on ambient conditions at the time of fill. This 
also ASSUMES no air or blended refrigerents in the system. To properly 
test the system you need the operating tables to know what the temps 
are supposed to be across the evap coil and the cond coil depending on 
the ambient temp. A general rule of thumb is a 20 degree drop over the 
evap coil means the system is working as long as the compressor isn't 
cycling too much.
David Teitelbaum
vin 10757


--- In dmcnews@xxxx, "Walter Coe" <Whalt@xxxx> wrote:
> Is there a way to determine if a system has the optimum amount of
> refrigerant in it without evacuating the system and recharging with 
a
> measured amount? There should be a way to top off a system without
> draining/refilling. Yes, I understand that a system should not be 
topped
> off if it is leaking, yadda, yadda. 
> 
> Walt Tampa, FL