Ultra Boiler Manual

Part number 550-100-440/0122
95
  
ADVANCED INSTALLATION
Continued after page 98
(see Figure 111, page 96 & Figure 112, page 97) (cont.)
make sure to connect the DHW circulator to termi-
nals1, 4 and7, as below:
4. e factory
default for space heating is designed for
nned-tube baseboard, and set up to activate Circula-
tor2 and Circulator3 on a call for heat. Connect the
boiler circulator to terminals2, 5 and8 and the system
circulator to terminals3, 6 and9 to use these default
settings.
5. Make sure the U-Control is programmed to activate
the system circulator when it is required (during space
heating, for instance).


Use isolating relays if using 3-wire zone valves
to avoid damage and nuisance problems due
to stray voltage.
1. e U-Control allows operation by up to three dierent
heating systems.
2. e factory default conguration is for “heat demand1”
to be DHW and “heat demand2” to be space heating.
For factory default operation:
a. Connect the space heating thermostat to terminal
strip P15, terminals1 and2 to use the default setup.
b. Connect the DHW tank temperature control across
terminal strip P11, terminals4 and5 to use the
default setup.
3. Install thermostats on inside walls away from the inuences of
dras, hot or cold water pipes, lighting xtures, television, sun
rays, or replaces.
4. ermostat anticipator (if applicable):
• If connected directly to the boiler, set anticipator for 0.1amps.
• If connected to relays or other devices, set to match total elec-
trical power requirements of connected devices. See device
manufacturers’ specications and the thermostat instructions
for details.

1. See the NOTICE on this page regarding internal low water protec-
tion provided by the U-Control.
2. When an external low water cut-o is installed, connect as shown
in the U-Control wiring diagrams (Figure111,page96 & Fig-
ure112,page97).
3. When possible, use the Weil-McLain Ultra low water cut-o kit
listed in the back of this manual. It includes a probe-type low water
cut-o and provides a simple harness connection for the wiring.


1. e U-Control and internal sensors in the Ultra boiler provide
both temperature control and low water protection (using
temperature senors), as explained below:
e U-Control module uses temperature sensors to
provide both high limit protection and modulating
temperature control.
e U-Control module also provides
low water
protection
by using a dual sensor to monitor the
temperature of the heat exchanger. [e U-Control
constantly monitors the sensor signals to ensure
they are within 10 °F of one another. If the sensor
dierence exceeds 10 °F, the boiler is shutdown on
automatic reset.] is method is accepted in many
areas as meeting the requirement for a low water
cut-o.
Some codes or jurisdictions may require additional
external controls for high limit and/or low water
cutoff protection. Follow the guidelines in this
manual to install additional controls when required.
Figure 110 Wiring to circulators