R-408A question(Evap temp) for low temp box

[jeremyjp]

For other Refer guys. Low Temp. Using R-408A, on a low temp box, what is the typical operation suction line temp/pressure?? at the evaporator? 24psi(-10) or 33psi(5 degrees)???

[VTP99]

Would depend on the equipment manufacturer.

[icemeister]

For other Refer guys. Low Temp. Using R-408A, on a low temp box, what is the typical operation suction line temp/pressure?? at the evaporator? 24psi(-10) or 33psi(5 degrees)???

Typically a walk-in freezer evaporator is selected for a 10ºF TD, where the TD is the Box temperature minus the evaporator temperature.

So for a 0ºF box you should expect a -10ºF evap temp. For R408A that would correspond to a pressure of 21 psig at the evaporator.

Smaller, self-contained freezers tend to have slightly higher TDs like 15ºF or so. Then your expected evaporator pressure would be correspondingly lower.

[markvilleman]

Typically a walk-in freezer evaporator is selected for a 10ºF TD, where the TD is the Box temperature minus the evaporator temperature.

So for a 0ºF box you should expect a -10ºF evap temp. For R408A that would correspond to a pressure of 21 psig at the evaporator.

Smaller, self-contained freezers tend to have slightly higher TDs like 15ºF or so. Then your expected evaporator pressure would be correspondingly lower.

Good info,so what TD for walk in cooler and self contained cooler? Thanks.

[2sac]

Good info,so what TD for walk in cooler and self contained cooler? Thanks.

Don't know if I've ever heard of 408a in a med temp application. Again, it depends on the mfg. Grab a manufacturerers catalog. You can design systems with different TD's.

[Fridge Repairer]

Good info,so what TD for walk in cooler and self contained cooler? Thanks.

Walk in coolers and self contained coolers are usually sized at 10 degree TD.
Air conditioners sized at 20 degree TD.