Nameplate Static Pressure and
Manufacturer Fan Data
Case Study
Ben Lipscomb
5 Ton Carrier Gas Pack
• 5 Ton Carrier Gas Pack
• Medium Static Fan Option
• Manufactured January 2013
• 0.8 in WC Max ESP
taken from a discussion board:
http://www.electriciantalk.com/f2/rtu-am-i-overthinking52626/
Model 48TCFA06A2A5AOAOAO
Key Information:
• 5 Ton
• Medium Static Fan Option
• 208-230/3/60
Product Data from Carrier:
http://dms.hvacpartners.com/docs/1009/Public/06/48TC19PD.pdf
SN 0213C82342
Key Information:
• Manufactured January 2013
48TC has been made since at least 2008 - Make sure the manual you’re using is for the
right vintage!
Electrical Data Key Information
• FLA for medium static
matches nameplate FLA –
proceed w/ confidence!
Key Observations
• Max ESP allows for motor to operate near full range of CFM (300-475 CFM/ton)
• Unit can still deliver 400 CFM/ton at 1.0” ESP (1.25xNameplate)
• Can deliver minimum allowable 300 CFM/ton at 1.6” ESP (2.0xNameplate)
• Operating at FLA at 0.8” would deliver 475 CFM/ton
• Increases SHR – good for hot+dry, bad for humid
• Increases kW demand ~9.5%, decreases EER ~7.5%, increases EERsensible
~3.5%
50 Ton McQuay VAV
Nameplate Data Key Information
• 20 HP Supply Fan
• Max ESP 2.5” WC
taken from a discussion board:
http://hvac-talk.com/vbb/showthread.php?1141011-McQuay-Unit-how-manytons
From manual (not shown)
• Max CFM ~21,400
• Min CFM ~6,250
• Nominal CFM 20,000
Key Observations
• Max ESP allows for motor to operate at full range of
CFM
• Could operate at higher ESP if Max CFM and capacity
isn’t needed
• Unit can still deliver 400 CFM/ton at 3.0” ESP
(1.2xNameplate)
• Unit can deliver 300 CFM/ton at 4.5” ESP
(1.8xNameplate)
Product Data:
http://lit.daikinapplied.com/bizlit/literature/lit_aa_rah/Catalogs/CAT2
50-1heating_and_cooling.pdf
Key Findings
For these 2 examples
• Nameplate Max ESP was max at which full
range of CFM could be achieved
• 400 CFM/ton can be achieved at 1.2 to 1.25 x
Nameplate Max ESP
• 300 CFM/ton can be achieved at 1.8 to 2.0 x
Nameplate Max ESP
• Not always best to operate at FLA – depends
on load characteristics