Watts AERCO EXT Installation, Operation & Maintenance Manual page 23

Ufly Controller and BCM for Modulex EXT
CHAPTER 4: UFLY SETUP AND PROGRAMMING
a. Setpoint/OAR Max Setpoint: the maximum allowable outlet water
(setpoint) temperature.
b. OAR Min Outside Temp: when outside temperature is at or below this
number, the unit setpoint will be the OAR Max Setpoint.
c. OAR Min Setpoint: the minimum outlet water (setpoint) temperature.
d. OAR Max Outside Temp: the maximum Outside Temperature that the
system will operate in. For example: if set to 68°F, the boiler will operate
between 68°F outside temperature and OAR Min Out setting.
6. Set Warm Weather Shutdown parameter to the threshold outside temperature
above which the unit shuts down. For example, if set to 70°F, when the outside
temperature goes above 70°F, the unit goes into standby. The unit will then
restart when temperature falls below 70°F.
7. Setpoint High Limit (upper limit of setpoint) and Setpoint Low Limit (lower
limit of setpoint) can also be set on this screen.
In addition to the Outdoor reset parameters, in Outdoor Reset Mode the unit's setpoint is also
influenced by the Building Ref Temp. For example, the graph below shows the setpoint curves
at 66°F, 68°F and 70°F Building Ref Temps for the following Outdoor Reset Schedule: OAR
Max Setpoint = 160°F, OAR Min Outside Temp = 20°F, OAR Min Setpoint = 100°F and OAR
Max Outside Temp = 68°F.
OMM-0159_A_A • 6/28/2022 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
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