134a discharge pressures

Posted by Hermann on September 19, 2009, 11:51 pm

Steve wrote:

>> 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.

How could any one miss those classes? They have free Pizza, pop, etc.

>
>
>

Posted by Stormin Mormon on September 20, 2009, 12:04 am

Busy fixing other stuff. I'll have to check at the parts
house one day soon.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.

How could any one miss those classes? They have free Pizza,
pop, etc.

Posted by The Daring Dufas on September 19, 2009, 2:00 pm

Stormin Mormon wrote:

> 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.
>

I think it may be because 134a was developed to work
most effectively in higher temperature applications.
I can't wait for HFO-1234yf to replace 134a. I'm
going to have problems remembering all those darn
numbers and letters. Sir, I'm sorry to inform you that
your refrigerator needs 2,3,3,3-Tetrafluoropropene.
Let me get my environmental suit and breathing air
tank. Hey, I get to charge more!

TDD

Posted by Stormin Mormon on September 19, 2009, 6:02 pm

I'm sure 134a works a LOT better at medium and high temp
applications. Well, it keeps ice cubes cold enough. Sure was
simpler when we only had four or five common gasses. Now,
we've got a real nightmare.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.

I think it may be because 134a was developed to work
most effectively in higher temperature applications.
I can't wait for HFO-1234yf to replace 134a. I'm
going to have problems remembering all those darn
numbers and letters. Sir, I'm sorry to inform you that
your refrigerator needs 2,3,3,3-Tetrafluoropropene.
Let me get my environmental suit and breathing air
tank. Hey, I get to charge more!

TDD

Posted by The Daring Dufas on September 19, 2009, 7:46 pm

Stormin Mormon wrote:

> I'm sure 134a works a LOT better at medium and high temp
> applications. Well, it keeps ice cubes cold enough. Sure was
> simpler when we only had four or five common gasses. Now,
> we've got a real nightmare.
>

Have you seen the new square and triangular shaped snap on
connectors for the new refrigerants? The manufacturers are
trying to make sure new and old refrigerants don't get mixed
up.

TDD

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134a discharge pressures - Page 2