Technical Guide

5005562-YTG-B-0715
Johnson Controls Unitary Products 19
UNIT TYPICAL ROOF CURB INSTALLATION
EXTERNAL STATIC PRESSURE SETUP
To measure external static pressure:
• Measure the supply air static pressure
• Record this positive number
• Measure the return air static pressure
• Record this negative number
• Treat the negative number as a positive and add the two numbers together
• This is total system static
SUPPLY
AIR DUCT
TO POWER SUPPLY
RETURN
AIR DUCT
FIELD-SUPPLIED
DISCONNECT
SWITCH
CONTROL WIRING TO
INDOOR THERMOSTAT
TO GAS
SUPPLY LINE
MANUAL GAS
SHUTOFF VAVLE
ROOF CURB
ROOF
CONDENSATE
DRAIN
A0326-001