Automatic Temperature Boost - Weil-McLain ULTRA ULTRA-105 Service Manual

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GAS FIRED WATER BOILER SERIES
See Figure 25, page 42 for procedure to access Parameter settings.
Parameter explanations

Automatic temperature boost

1. If the target temperature happens to be too low for the heating units to
supply sufficient heat within ten minutes (default setting), the control
"boosts" the target temperature until the supply water meets the system's
needs. See Figure 29, page 46.
2. Even if the reset parameters are optimized for the application, use of
setback thermostats or the need for occasional cold start operation will
require faster recovery than provided by the normal calculated supply
water temperature because the curve assumes steady-state operation.
3. Boost will not call for supply water temperature setpoint greater than
the value of parameter 4 (T1
boost would supply water too hot for low-temperature systems, such as
slab-type radiant heating. On hybrid systems, with finned tube radiation
and radiant slab, provide additional low temperature protection for the
radiant portion of the system, because parameter 4 (T1
be set higher than on a radiant-only system.
Many slab-type radiant systems won't require boost. This
function can be disabled with a parameter setting of "0."
Parameter 11 — Automatic supply temperature boost operation — In the example below, the boiler is operating
in outdoor reset mode, with a calculated setpoint temperature of 130°F. The call for heat has lasted for more
than 10 minutes (value of parameter 11), and supply temperature boost has occurred.
46
1 & 2
). There is no concern that temperature
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—
(continued)
Boost operation
1. In outdoor reset operation (outdoor sensor con-
nected), the Ultra control module automatically
increases the target outlet water temperature if a call
for heat exceeds a time equal to parameter 11 (fac-
tory default of 10 minutes for most Ultra boilers).
2. At each interval of parameter 11 of a continuous
call for heat, the control module increases the target
temperature by 18°F.
3. The control module will continue increasing target
temperature until it reaches the value set in param-
eter 4 (T1
4. When the call for heat ends while target temperature
is "boosted," the target temperature drops about 2°F
for each minute the thermostat is open.
) is likely to
5. Range = 1 to 30 minutes.
6. Factory default setting = 10 minutes.
7. Deactivate automatic temperature boost by setting
to "0."
).
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Part number 550-100-029/0810