134a

[roosel]

I am an inexperienced tech and have never worked with 134a. Today I was asked to check out a rooftop unit with 134a. what are the normal operating pressures for 134a? I know r-22 is around 70 to 75 on the low side and around 225 on the high side.

[jpsmith1cm]

A rooftop AC unit with R134a as a refrigerant?

[roosel]

I'm guessing it was for a cooler? it is on a resturaunt.

[Burnedout]

chiller?

[roosel]

I don't know. my boss told me to connect my guages and tell him the pressures. he wanted me to do this because he saw the suction line was frosted. I am sorry i could not be more specific.

[roosel]

when I asked him what they should be he told me that it depends on the size of the unit. I am beginning to think I know more about HVAC than he does. either way I am beginning to doubt him. and will surely have more questions in the future.

[jpsmith1cm]

So, what were the pressures?

Now this is making a bit more sense...


Did you take any measurements beyond pressures?

[ryan1088]

Wow?? Help us help you. Model? What it is? Pictures? Anything?!

[carmon]

134a my least favorite refrigerant....... I hate it...........

[roosel]

I apologize for the lack of details. this is my first post. I believe it was close to 2 tons. Again I apologize in advance for my poor memory. the label was worn and I almost mistook it for a 22 unit like the one next to it. I believe the pressures were like 25 psi on the low and 150? on the high. My boss told me to charge it so I did. just enough to melt the frost on down the line but it melted slowly. he told me that was good. but I didn't feel in my gut that he knew.

[carmon]

well ..... I assume he new something....

[beenthere]

I think you mean the condenser was on the roof.

Learn to ignore the pressure readings as a way to check charge. And learn to read and use saturation temps.

[timebuilder]

I apologize for the lack of details. this is my first post. I believe it was close to 2 tons. Again I apologize in advance for my poor memory. the label was worn and I almost mistook it for a 22 unit like the one next to it. I believe the pressures were like 25 psi on the low and 150? on the high. My boss told me to charge it so I did. just enough to melt the frost on down the line but it melted slowly. he told me that was good. but I didn't feel in my gut that he knew.

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