Weil-McLain -230 - Manual (Page 9)

GAS
-
FIRED WATER BOILER SERIES
2 — Control Supplement
Part number 550-100-029/0404 9
Operating information
Ultra Control Module
The Ultra boiler is controlled by a microprocessor
electronic control — 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 operating
controls) to regulate boiler on/off operation and can
modulate boiler firing rate to more closely match output
to demand.
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:
Level 1 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.
Level 2 Lockout would occur if supply or return water
temperature 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
technician 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.
Outdoor reset operation, if used
Target temperature with outdoor reset
All Ultra boilers are shipped with an outdoor temperature
sensor. When this sensor is installed (low voltage terminal
strip terminals 1 and 2), the control module regulates
target outlet water temperature based on outside
temperature.
Set the temperature curve by setting Parameter 4 to:
• ODT (outdoor design temperature for the area).
• For ODT of 32°F or lower:
• Set Parameter 4 to the desired supply temperature at
the ODT.
Electrical specifications
Ultra boilers require 120 VAC /60 HZ power supply and are
not polarity sensitive.
Control module specifications
•
Supply voltage 120 vac / 60 hz
• Electrical demand 10 va
• Prepurge timing 10 seconds
• Postpurge timing 15 seconds
• Min. off time, space heating 1 minute
• Pump run on after space htg. 10 seconds
• Min. off time, DHW 0 seconds
• Pump run on after DHW 30 seconds
• Line voltage fuse, F1 5 amp fast-blow
• Low voltage fuse, F3 4 amp slow-blow
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 — Target temperature is fixed (equal
to Parameter 4) when outdoor reset is not installed.
• Space heating — 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.
High limit operation
If outlet water temperature exceeds target temperature
(or 190°F, 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.
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