R134a to 404

[devlin maguire]

Can R404a be used in a fridge instead of R134a
Dev

[AlexG]

No, you can't.

[devlin maguire]

I was at a job changing a fan motor and a label was wrapped round the charging tail "changed to r404a" looks like I will be back at some point
Dev

[Tayters]

At least someone was kind enough to let you know!

Was a new compressor fitted (can't think why else the change of refrigerant - and that's not a good reason either!). Therefore the rest of the system is primed up for a different refrigerant. In the lap of the Gods then as to how well it would perform.
Both types would use a POE oil I think, so other than wrongly sized components I can't see why it wouldn't completley fail.

Or maybe that is the reason why...

Hmmm,
Andy.

[mad fridgie]

Yes you can, a small displacement compressor will give the same duty, "only concern would be the expansion device".
If the same compressor, more duty, lower SST and a higher SCT, higher current, and if these figures are within operating range of the compressor, then no issues for the system. product in the fridge may dry out quicker. Efficiency would also be less.

[mikeref]

Yes you can, a small displacement compressor will give the same duty, "only concern would be the expansion device".
If the same compressor, more duty, lower SST and a higher SCT, higher current, and if these figures are within operating range of the compressor, then no issues for the system. product in the fridge may dry out quicker. Efficiency would also be less.
I beg to differ...as the phrase goes. Compressor will have a much harder time trying to start and then the condenser will be undersized. Now i spin my hand gun from side to side as in the movie "Tombstone";).. Mike.

[mad fridgie]

I beg to differ...as the phrase goes. Compressor will have a much harder time trying to start and then the condenser will be undersized. Now i spin my hand gun from side to side as in the movie "Tombstone";).. Mike.

and you should differ, if you think I am wrong,
Most compressors can be used on either refrigerant, it boils down to what the working envelope of the compressor is. If a new compressor was fitted but with a small displacement, so that the duty matched the working conditions of the present evap and cond, then all would be OK as long as the comp was designed to run at those conditions.
If the same compressor was used (and still within the working envelope) then the evap and cond would effectively be to small. Equalibrium will be reached, this achieved by reducing the evap temp (increasing the TD which increases the duty of the evap) and increasing the cond temp (increasing TD which increases the duty of the cond.) as long as the new working conditions are within the working envelope, then there are no issues. (expansion device does need to be changed)
This type of change should only be undertaken if you have compressor data at hand.

[mikeref]

True..That makes sense. Going by Devlin's post i assumed, (nasty word), that if a fridge, as in domestic fridge that was running R134a, were to be changed to R404a, then could it work. Commercial compressors can run either/or and be selected to suite the application. Suppose one could even go to the trouble of changing domestic compressor to run R404a after matching capacity against charts, -6.7 or -23.3c.. BTW, hope your ground tremors are easing up. Anticipation of what might happen next must be very stressful to everyone in Christchurch..Mike.

[devlin maguire]

This is a commercial 3 door SS prep, +5/-0, GL90TB R134a but with 404 it looks like a new comp or at least it not the original I would say it 2 years old but the fridge is a recent aquisition and has lain unused for some time,
Dev