Re: 4000 A/C Question, Low speed fan

["Graydon D. Stuckey" <graydon@apollo.gmi.edu>]

On Thu, 19 Jun 1997, Scott M. wrote:

>  The cooling ability of the AC system will be compromised
> as you are unable to remove the heat from the high pressure
> gas and convert it to a liquid. Some aftermarket systems

Scott is right - this is crucial to the operation of an A/C system.

> When servicing air conditioning systems in a closed shop we
> often had to place a large electric fan in front of the
> radiator/condenser on vehicles that used an engine driven
> fan to keep the A/C high side pressure from getting out of
> control.

One of the noise tests I do is to run the system at a constant 300psi to 
evaluate the compressor growl.    To accomplish this, we have a fan 
controller that runs an electric fan in front of the A/C condensor.   If 
the pressure drops, we slow down the fan, as the pressure rises, we 
increase the fan speed.   I am amazed how fast the system responds.   If 
the fan were turned off, you'd see a very fast rise in pressure which can 
ruin compressors adn blow holes in the A/C system.

Its all pretty simple really, but you have to have the basics.  You need
fans that work, a compressor that compresses, the right amount of
refrigerant, an expansion valve, and proper airflow through both the
condensor (that's the one that goes in front of the radiator) and the
evaporator (that's the one in the passenger compartment, near the fan.)

Later,
Graydon D. Stuckey