Weil-McLain Ultra 3 series User Manual page 84

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gas fired water boiler
U-Control operation and setup — advanced
e. Connect these output terminals to the
SHADOW boilers' 0–10 VDC input termi-
nals, P15 #5 and #6. The SHADOW boilers
will start and modulate based on the signal
strength. The SHADOW boilers must be set
up as Type 4 (see below). They do not need
their additional heat timers to be setup.
f. An alternate method is to daisy chain the
other boilers. That is, connect the output
of each to the input of the next. Each of
these boilers would be set up as a Type 4
(see below), and each needs its additional
heat timer set for the desired delay between
boilers.
7. Type 4 — This assigns the boiler as a SHADOW
boiler in a multiple boiler system.
a. The boiler can be wired and setup to run in
parallel with the other SHADOW boilers
as in 6c, above. Or they can be set up for
sequential operation following 6d, above.
b. When the boiler receives a 0–10 VDC in-
put on terminals P15 #5 and #6, it starts
up and modulates firing rate according to
the signal.
c. If wired and setup per 6d above, it also
starts its additional heat delay timer imme-
diately. When the delay timing is reached,
the U-Control sends out a 0–10 VDC signal
(on terminals P16 #1 and #2) for the next
boiler.
d. The boiler uses the settings for Priority 1
while receiving the 0–10 VDC signal.
ADVANCED SETUP –
PRIORITY 1, 2, 3
1. Priority 1, 2 and 3 refer to the three possible
heating inputs that can be handled by the U-
Control.
2. Select the priority level desired for the applica-
tion. Priority 1 is usually assigned to domestic
water heating, because of the need for quick
response. Priority 2 and 3 usually used for
space heating circuits.
3. Each of the three inputs has its own set of
operating parameters, programmed using the
menus shown in Figure 102, page 86.
4. The inputs to the U-Control are:
a. Priority 1 — P11 #4 and #5, "heat de-
mand 1"
b. Priority 2 — P15 #1 and #2, "heat de-
mand 2"
c. Priority 3 — P15 #3 and #4, "heat de-
mand 3"
84
— Boiler Manual
ADVANCED SETUP –
SYSTEM TYPE
1. For each priority being used, select the appropriate
system type. See Figure 101, page 85 for system options
and preset temperatures.
2. The temperature presets are chosen based on normal
best setting for these systems. The temperature values
can be changed, if desired, under "TEMPERATURES."
ADVANCED SETUP –
TEMPERATURES
1. Setup desired temperatures for each of the priorities
used.
2. For an explanation of the target temperatures and as-
sociated outdoor temperatures, see Figure 100.
a.
b.
c.
Figure 100
Modulate on differential
3.
drop this many degrees below target temperature for
the boiler to come on.
Modulate off differential
4.
firing, as the temperature increases above the target
temperature, the boiler firing rate is reduced. At this
many degrees above the target temperature, the boiler
shuts down.
Outdoor temp for max target means the outdoor
temperature at which the target temperature reaches
its maximum value. In the example of Figure 100,
this occurs at 25 °F outside.
Outdoor temp for min target means the outdoor
temperature at which the target temperature reaches
its minimum. In the example of Figure 100, this
occurs at 70 °F.
Note that the reset lines are curved. The shape of this
curve is matched (or characterized) to the response
of the system type chosen to ensure the most effec-
tive reset operation.
Typical outdoor reset curves
— The temperature must
— While the boiler is
Part number 550-100-090/0809
(continued)