Ultra Phd Control Module; Electrical Specifications; Boiler Temperature Regulation; Low Water Protection - Weil-McLain ULTRA ULTRA-105 Service Manual

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GAS FIRED WATER BOILER SERIES

Operating information

Ultra Control Module
The Ultra boiler is controlled by a microprocessor electronic con-
trol — the Ultra Control Module. The module senses outlet
water temperature, return water temperature, flue temperature
and outdoor temperature (when outdoor sensor is installed). It
uses this information (plus input from external limit and operat-
ing controls) to regulate boiler on/off operation and can modulate
boiler firing rate to more closely match output to demand.
Electrical specifications
Ultra boilers require 120
VAC
ity sensitive.
Control module specifications

Boiler temperature regulation

Operating temperature (target)
The Ultra control module senses outlet water temperature and
regulates boiler firing rate to achieve a target temperature, set by
installer, by setting Parameter 4. Temperature can be set between
70°F and 190°F. See page 18 for procedure.
Space heating with fixed temperature — Target temperature
is fixed (equal to Parameter 4) when outdoor reset is not
installed.
Space heating with outdoor reset — Target temperature is
calculated as described under "Outdoor reset operation" when
outdoor sensor is connected. Exception: See explanation of
"Supply temperature boost."
DHW heating — Target temperature is 50°F + Parameter 1.
Do not change parameter 1 from the factory default setting
of 140°F unless the application is specially engineered for
other temperature.
Part number 550-100-029/0810
/60 power supply and are polar-
HZ
—
1 & 2
High limit operation
If outlet water temperature exceeds target temperature plus OFF
differential (or 190°F plus OFF differential, whichever is lower),
high limit action occurs. The control module shuts the burner
off.
DHW operation (if used)
The boiler is factory set to immediately change target outlet
water temperature to 190°F on a call for heat from the DHW
aquastat.
Additional Thermal Overrun Protection
High limit operation shuts down the burner when the outlet water
temperature exceeds the target temperature. However, adverse
conditions could cause the water temperature to rise too quickly,
overshooting this temperature. The Ultra control module's
technology provides advanced protection in the event of thermal
overrun. Using its electronics, the Ultra control module provides
two additional levels of overrun protection:
Indication would occur if supply or return water
temperature reached 203°F. The Ultra control module
would display a soft lockout code ("b" followed by "18"
if on the supply, or "19" if on the return). The module
would not operate the burner again until the water
temperature dropped 9°F below target temperature.
Lockout would occur if supply or return water tempera-
ture reached 210°F. The Ultra module would enter hard
lockout and display an error code ("E" followed by "18"
if on the supply or "19" if on the return). NOTE: Hard
lockout requires manually pressing the Ultra display
panel reset button to restart operation. Service techni-
cian must troubleshoot the cause of the problem and
correct it before placing the boiler back in operation.

Low water protection

1. The control module uses temperatures sensed at both supply
and return areas of the heat exchanger. If the flow rate is too
low (temperature difference too high) or either temperature
is too high, the control module shuts the boiler down. This
ensures boiler shutdown in the event of low water or low
flow conditions.
2. Some codes and jurisdiction may accept these integral features
of the control in lieu of requiring an additional limit control
or low water cutoff. Consult local jurisdiction to determine.
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