Weil-McLain ULTRA299-S4 Manual page 100

S 4
®
ERIES
U-Control operation and setup — advanced
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 input on
terminals P15 #5 and #6, it starts up and modu-
lates fi ring rate according to the signal.
c. If wired and setup per 6d above, it also starts its
additional heat delay timer immediately. 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 application.
Priority 1 is usually assigned to domestic water heat-
ing, 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 115, page 102 .
4. The inputs to the U-Control are:
a. Priority 1 — P11 #4 and #5, "heat demand 1"
b. Priority 2 — P15 #1 and #2, "heat demand 2"
c. Priority 3 — P15 #3 and #4, "heat demand 3"
ADVANCED SETUP –
SYSTEM TYPE
1. For each priority being used, select the appropriate
system type. See Figure 114, page 101 for system op-
tions and preset temperatures.
2. The temperature presets are chosen based on nor-
mal best setting for these systems. The temperature
values can be changed, if desired, under "TEMPERA-
TURES."
ADVANCED SETUP –
TEMPERATURES
1. Setup desired temperatures for each of the priori-
ties used.
2. For an explanation of the target temperatures and
associated outdoor temperatures, see Figure 113 .
100
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GAS FIRED WATER BOILER
— Boiler Manual
a. Outdoor temp for max target means the outdoor temperature
at which the target temperature reaches its maximum value. In
the example of Figure 113 , this occurs at 25 °F outside.
b. Outdoor temp for min target means the outdoor temperature
at which the target temperature reaches its minimum. In the
example of Figure 113 , this occurs at 70 °F.
c. 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 effective reset operation.
Typical outdoor reset curves
3.
many degrees below target temperature for the boiler to come on.
4.
temperature increases above the target temperature, the boiler
fi ring rate is reduced. At this many degrees above the target tem-
perature, the boiler shuts down.
(continued)
— The temperature must drop this
— While the boiler is fi ring, as the
Part number 550-100-400/0717