Can I use a 30 KBTU compressor/cond with a 42KBTU coil? 1

[HighPotential]

I need to increase my airflow but don't want ot purchase a new compressor. My fan unit is capable of 1450CFM but my current 30KBTU coil is rated 1150 max. Can I simply replace the 030 coil with an 042?

Thanks!

 

[mdonner]

The answer is no, and this is why:
Increased coil area and increased airflow, assuming coil temp does not increase, means more Btu/hr absoarbed from the conditioned space. To handle this, the condensing unit will have to increase condensing temp, lowering compressor capacity, when actually capacity increase is required.
This imposes raise in suction temp, which lowers the heat absorbed by fan coil.
Eventually the system will balance at higher head pressure and suction pressure, with some increase in pumped heat from indoor to outdoor.
Such a big difference in nominal capacities (42/30 -> 40%) indicates a too big mismatch in units, which will cause compressor overload.
If you can supply the design figures leading to 1450 cfm fan coil with 30K Btu/hr condensing unit, the answer may be much more specific and precise.