Ultra Boiler Manual
Part number 550-100-440/0122
98
(see Figure 111, page 96 & Figure 112, page 97) (cont.)
1. e U-Control allows connection of external limit controls,
both for manual reset and for automatic reset operation of the
U-Control.
2.
Manual reset of the U-Control on limit action — Connect
external limits across P13, terminals1 and2 if the U-Control is
to require manual reset when a limit opens, even if the limit re-
closes. (Remove the factory jumper when using these terminals.)
e U-Control will lockout when a limit in its manual
reset circuit opens. e U-Control activates its alarm
terminals and shuts the boiler down until an operator
manually resets the U-Control (as explained in this
manual). is reset function can be done by a home-
owner or a service technician.
3.
Automatic reset of the U-Control on limit action — Connect
external limits across P13, terminals3 and4 if the U-Control is to
reset automatically when the limit circuit closes aer a limit con-
dition. (Remove the factory jumper when using these terminals.)
1. e U-Control module provides terminals to input a remote
0–10VDC operating signal. is can be provided by a separate
controller if the boiler is congured as Type4 (SHADOW boiler
mode).
2. Connect the 0–10VDC signal positive terminal to P15 termi-
nal6, and the signal common to terminal5.
3. When receiving a remote operating signal, the boiler starts when
the signal exceeds 1.0VDC (and shuts o if the signal drops
below 0.5VDC). e boiler remains at low re until the signal ex-
ceeds 2.0VDC. Between 2.0and 10.0VDC, the boiler ring rate
increases with the signal value, reaching full input at 10.0VDC.
4. e U-Control continues to monitor boiler temperatures, based
on the values set up under Priority1 operation. See the following
section for details.
1. e U-Control module can be set up to activate another heat
source using its additional heat demand dry contracts (P16,
terminals6 and7).
2. Connect these terminals to call for heat from the other heat
source. (See the following section to program the boiler to ac-
tivate the other source, either as the primary or secondary heat
source.)
(low voltage ONLY)
1. e U-Control’s alarm dry contact (P16, terminals4 and5) closes
when the boiler enters lockout.
2. Connect these terminals for remote alarm notication.
1. e U-Control can be programmed to sequence multiple boilers
or operate/modulate in tandem from a 0–10VDC source gener-
ated by the lead boiler or from a remote controller.
2. See “ADDITIONAL HEAT DEMAND” on page99 for recom-
mended wiring.
Outdoor temperature sensor
1. e U-Control provides programmable options when
using an outdoor temperature sensor. is sensor is
supplied with the boiler, and can be used if desired (not
required). See the following section for outdoor tem-
perature options.
The outdoor sensor must be
Energy Act statement on page 137.
2. Mount the outdoor sensor on an exterior wall, shielded
from direct sunlight or ow of heat or cooling from
other sources.
3. Connect the sensor leads to P10, terminals1 and2, as
shown in the wiring diagrams. ermostat wire can be
used to connect the sensor.
temperature sensors
(see Figure 4, page 11 for placement of sensors)
1. e boiler is also shipped with two strap-on temperature
sensors, intended for system supply and return.
2. ese sensors can be attached to piping up to 3-inch
diameter.
3. ermostat wire can be used to connect these sensors.
4. e system supply temperature sensor allows the U-Con-
trol to regulate temperature in the system main piping.
5. Locate the supply sensor at least six pipe diameters, but
no further than 3 feet, downstream from the boiler con-
nection to the main to ensure adequate mixing.
6. e system return sensor allows the U-Control to moni-
tor and display system return temperature.
7. For multiple boiler applications, install a system supply
temperature sensor and system return sensor wired to
the LEAD boiler.
8. e U-Control also compares the system return tem-
perature with the system supply temperature. Should the
return temperature ever exceed the supply temperature,
the U-Control knows there is likely a sensor failure and
will report this problem on the display.