Re: A/C recharge questions

[Thomas Tornblom <Thomas.Tornblom@nexus.comm.se>]

> Date: Thu, 8 Sep 94 07:19:55 -0400
> From: "Barton P. Chambers"  <bchambers@atlantic.nos.noaa.gov>
> Reply-To: quattro@swiss.ans.net
> X-Charset: LATIN1
> X-Char-Esc: 29
> 
> Hi Vladimir,
> 
> > Why the Bentley recommends to evacuate system before recharging?
> 
> This procedure applies to *all* conventional air conditioner systems using 
> refrigerant under vacuum.  If you wish to successfully charge one of these 
> systems, it is *absolutely* essential to pump out the remaining refrigerant
> under vacuum, or you *will* get air in your system, and lose the ability
> to cool.
> 

What do you mean by "refrigerant under vacuum"? Conventional (R-12, R134A)
A/C:s are under pressure when correctly charged.

Unless you have a leak and the whole charge has vanished it is
possible to recharge without evacuating the remainder. If there is a
leak and air (= moisture) has gotten into the system the moisture must
be evacuated, after fixing the leak of course, as R-12 reacts with
water into some acid.

One reason I can see to evacuate the system is to know exactly how
much refrigerant you have in the system.

Thomas