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Posted by Steve on September 19, 2009, 9:02 am
>I work on some old equipment (ice chests, from Leer). The
> older R-12 units used to run about 150 to 170 discharge
> pressure. The R-134a units run more like 225 to 250 or so.
> Anyone else seen this?
> http://dodgeram.org/tech/repair/HVAC/R134a.htm
> Some online checking shows that's about normal. Seems a bit
> unusual, after working with R-12 all these years. For the
> first few degrees, the temp F and the PSIG are about the
> same. But when it gets hot, the pressure takes off.
> I can tell that getting used to 410a is going to take a
> while.
R410a is like any other refrigerant... it has to be charged by superheat and
subcooling. The only real difference is that the pressures are
approximately 1.6 times higher than R-22..... other than that, there isn't
any "gettin used to". But if you had gone to any of the R410a classes put on
by manufacturers and supply houses, you would know this.
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> older R-12 units used to run about 150 to 170 discharge
> pressure. The R-134a units run more like 225 to 250 or so.
> Anyone else seen this?
> http://dodgeram.org/tech/repair/HVAC/R134a.htm
> Some online checking shows that's about normal. Seems a bit
> unusual, after working with R-12 all these years. For the
> first few degrees, the temp F and the PSIG are about the
> same. But when it gets hot, the pressure takes off.
> I can tell that getting used to 410a is going to take a
> while.