438a in a 410a

[waterworksdan]

Does any one know what would happen if a 410a unit were vacuumed and filled with 438a (mo99)

[rider77]

That’s an R22 substitute refrigerant.
P/T charts are much different. I’d say it’ll run about as well as using 22 in a 410 system.

[BennyD]

That’s an R22 substitute refrigerant.
P/T charts are much different. I’d say it’ll run about as well as using 22 in a 410 system.

Which is not well?! Hahaha

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[rider77]

Which is not well?! Hahaha

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Would not be an advised thing to do, that’s for sure.

[waterworksdan]

Being well aware of the differences in the two refrigerants, and the advisability, my question remains, would the compressor, not compress the gas, over compress and vaporize it, blow up, whistle Dixie, would it not condense, would or not flash, evaporate, would the metering device go nuts or stop up, to high amp's at comp to low amp's?? Thanks

[VTP99]

Try it and give us the results

[pecmsg]

What test question is this!

[BennyD]

If I remember right from another thread, the pumping capacity of a 410 compressor is roughly 30% less than a 22 compressor. In that regard, it'll act like either a weak compressor or the condenser, evaporator and metering device are over sized. May have issues with oil return due to lower velocity. I would venture a guess of high subcooling and low superheat if the TXV couldn't choke down far enough.

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[waterworksdan]

Thanks benny d!

[Anisha]

How it is possible to run R438a in the compressor which is designed for R410a is that possible?

[pecmsg]

How it is possible to run R438a in the compressor which is designed for R410a is that possible?

The compressor doesn't know or care. Its design to pump, it pumps what it can.

No the compression ratios are going to be way off

[icemeister]

There would be a reduction of capacity of 40% or so when using MO99 or R22 in a R410A condensing unit meaning a 5 ton R410A unit would be roughly equivalent to a 3 ton. If you match it up with a 3 ton evaporator with a properly sized metering device it would run normally, like any other R22 or MO99 system.

It's all about the difference in the compressor displacements (cu ft/min) between the R410A and R22 compressors. The R410A compressor simply pumps 40% less volume of gas.

[VTP99]

The density of the gas type must come into play here somewhere yes ?

[pecmsg]

The density of the gas type must come into play here somewhere yes ?

that and Lacquer Thinners!

[icemeister]

The density of the gas type must come into play here somewhere yes ?

The suction vapor density difference is just another way of comparing the relative capacities. My example is a comparison of the required compressor displacements.

To do the calculations, go here: (See #3 and #18) https://icemeister.net/backroom/wp-c...lculations.pdf

[VTP99]

The suction vapor density difference is just another way of comparing the relative capacities. My example is a comparison of the required compressor displacements.

To do the calculations, go here: (See #3 and #18) https://icemeister.net/backroom/wp-c...lculations.pdf

Thanks icemeister. My thought was the compressor displacement is designed around the gas being used. Correct ?

[icemeister]

Thanks icemeister. My thought was the compressor displacement is designed around the gas being used. Correct ?

Yes, it's basically a matter of scaling the displacement up or down to get the capacity you need. A manufacturer will come out with a "family " of compressors which are optimized for specific refrigerants like R410A, R404A, etc and for specific applications like high temp. low temp, etc. Copeland rates some models for a number of alternate refrigerants and applications.

This "optimization" usually involves designing the scrolls for a particular refrigerant and application to boost efficiency at specific conditions.

[shellkamp]

Thanks icemeister. My thought was the compressor displacement is designed around the gas being used. Correct ?

Yeah, based on the enthalpy of the refrigerant at the conditions the system would need to operate at, which dictates the volume that the compressor needs to move.

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[Poodle Head Mikey]

It would operate at about 65% of the R-410 unit's rated capacity.

PHM
-------

Does any one know what would happen if a 410a unit were vacuumed and filled with 438a (mo99)

[Poodle Head Mikey]

If the R-410 system metering device was a fixed orifice - it would operate well but at about 65% capacity as compared to R-410.

If the R-410 system's metering device was a TXV it would tend towards low suction superheat - because, to a R-410 TXV, the suction pressure (a closing force) would appear to be "too low" to the TXV.

PHM
--------

Being well aware of the differences in the two refry the igerants, and the advisability, my question remains, would the compressor, not compress the gas, over compress and vaporize it, blow up, whistle Dixie, would it not condense, would or not flash, evaporate, would the metering device go nuts or stop up, to high amp's at comp to low amp's?? Thanks