Assuming you have an AHRI matched system, I would match CFMs/ton to your comfort and conditions. Most installers would set to 400 CFMs/ton which would be correct for most installs.
IMO
If a system has an evaporator which is a half ton larger than the condenser, should the blower speed ideally match the tonnage of the evaporator or the condenser?
Assuming you have an AHRI matched system, I would match CFMs/ton to your comfort and conditions. Most installers would set to 400 CFMs/ton which would be correct for most installs.
IMO
Match to design CFM and Manual S. When commissioning you are allowed +- 15% of design
A 3 ton evaporator would require 1200 cfm and a 2.5 ton condenser would require 1000 cfms. So if a 2.5 ton condenser is matched with a 3 ton evaporator, are ther opinions for what the ideal blower speed should be? I assume there would be a tradeoff of sensible heat transfer and humidity removal.
What size drive is your furnace? If you have a (3) ton drive with furnace common, paired with (3) ton coil and (2.5) ton condenser. The installer can adjust the speed of the blower to match the outdoor unit. There should be a blower performance sheet which the furnace that will show all the rated cfm at certain static pressures.
Ideally with a (2.5) ton condenser you would want the system to be moving 1000cfm which is 400 cfm per ton. Depending on the static presure and layout of the duct system he or she should be able to get the furnace dialed into the correct cfm within reason.
They can then use a flow hood to confirm the supply and return are delivered the rated cfm needed for the (2.5) ton system to work proprerly . That is if the system is rated together.
If it is an older air handler with a new replacement install, U actually can't depend on static pressure readings.
Check the blower wheel for lint build-up & the duct system for supply air leaks as those conditions will show on the blower chart a low static pressure & a resultant much higher CFM airflow than actually exists.
Always match CFM to the condenser's tonnage & its CFM Ratings.
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udarrell