24
RPB-IOM (06-22) 131782-B
CONTROLS—CONTINUED
Optional Two-Stage Control (Makeup Air Application)
• Two-stage makeup air units are equipped with a two-stage gas valve, but instead of control from a two-stage
room thermostat, the outlet air temperature is monitored and controlled by a two-stage ductstat. When discharge
air temperature drops to the setpoint, low fire is energized. If low fire cannot satisfy the ductstat setting, high fire
is energized.
• Makeup air applications are usually adjusted to maintain discharge air temperature between 65°F and 75°F. In
all applications, the allowable temperature rise of the furnace in the installation dictates the limits of the ductstat
temperature setting.
• Depending on the option selection, the factory-installed sensor is either field-connected by capillary tubing to the
unit-mounted ductstat (see Figure 11), which is factory-set at 70°F, or electrically-connected to a remote electronic
temperature selector (see Figure 12).
Figure 11. Unit-Mounted Ductstat (Option AG3)
Figure 12. Remote Temperature Selector (Option AG15 or AG16)
Optional Ductstat with Capillary Tubing (Option AG3)
The unit-mounted ductstat shown in Figure 11 has an adjustable range between 0°F and 100°F with a fixed differential
of 3°F. Due to different cfm settings and outside air temperatures, the average downstream outlet temperature may
not match the ductstat setting exactly. After the installation is complete, adjust the setpoint of the ductstat to achieve
the desired average outlet air temperature.
A = TEMPERAT URE-SELECTING MODULE
B = ONE-STAGE ADDER MODULE
To Next Page
Loading...
