Hi Harry, hope you are having a nice day

On 04-Aug-04 At About 22:09:36, Harry Conover wrote to All
Subject: more fun with air conditioning

HC From: (Harry Conover)


HC Your technician was correct. He would determine if it was operating
HC at 100% though use his gauge set for pressure measurements,
HC and the temperatures measured on the evaporator and condensor
HC coil surfaces to approximate this determination.

Not on coil surfaces but Line temps as in superheat and sub cooling.


HC So long as the freon in the system is at a sufficent level to
HC continuously provide bubble free liquid in the high pressure line, it
HC makes little difference in the operating characteristics of the air
HC conditioning system.

wrong again. in some systems you want bubbles in the liquid column such as in
a piston type metering device.

HC In fact, larger industrial systems always include a view port in the
HC liquid freon line to check for excess bubbles. Too many bubbles
HC may also reflect a need for the addition of freon to the system
HC or the installation of the system was faulty and contains trapped
HC air.

actually the sight glass is only supposed to be used only for moisture
indication. the only proper way to check is gauges using superheat and/or
subcooling depending on metering device.

HC A refrigeration gauge set is incapable of revealing this information,
HC and indicates only that the pressures in the low and high pressure
HC sides of the system are consistent with the particular variety
HC of freon in use for the measured surface termperature on both the
HC condensor and evaporator coils. It reveals very little helpful
HC information about the adequacy of the freon charge in the system.
HC Usually a pocket sized card for the freon in use (typically
HC Freon-22 in small to medium size -- 3 to 30 tons -- central A/C
HC systems).

HC On smaller home systems which lack a view port, most competent
HC refrigeration techs will, after checking the operating pressures,
HC charge the system up to the point where frost begins to appear on the
HC evaporator low pressure tube fitting. This is the point of optimal
HC cooling and presumably optimal system efficience.

wrong again. as I said before. the only way to properly charge a system is by
superheat or subcooling. this "frost back" method is sure early death for a
system.

HC I'm not a refrigeration engineer

It's quite obvious to anyone in the trade.


-= HvacTech2 =-


... Fault lies with systems not the technologies involved.

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