ECR International Utica Boilers UB90-50 Installation, Operation & Maintenance Manual page 35

SETTING
Disables economy function. Will allow boiler to fire
until hi-limit temp is reached and re-fire with a 10°
OFF
subtractive differential.
Provides lowest level of fuel savings. Use this set-
LO ting only if the house does not stay warm at higher
settings.
1 Recommended setting for single zone systems.
2 Recommended setting for Two zone systems.
Recommended setting for Three zone systems.
3
4 Recommended setting for Four zone systems.
Recommended setting for Five zone systems.
5
HI Provides highest level of fuel savings.
C - Differentials
Differentials are automatic and will vary based on the
control settings and boiler temperature.
3 - Gas Control Valve
Electrically controlled Combination Gas Control Valve is
designed to meet requirements for use with hot surface
ignition found in this boiler. Valve is piped to gas/air mixer.
4 - Hot Surface Igniter
Igniter is mounted next to burner through gas/air mixer.
The igniter also serves as means for proving main burner
flame by flame rectification. In the event of a lack of flame
signal on three (3) consecutive trials for ignition, IBC will
flash the VALVE light when locked out due to failed ignition.
5 - Draft Inducer Temperature Safety Switch
Draft Inducer Temperature Safety Switch is a disc
thermostat (180°F setpoint) located on induced draft fan
outlet port. Switch protects inducer and vent pipe from
potential high temperature condition for discharging flue
gases. Condition would typically be result of higher high
limit control setting or over firing. Temperature safety
switch automatically resets when the vent temperature
decreases. (15°F switch differential).
6 - Casting Temperature Safety Switch
In event of lack of or loss of water in boiler, Casting
Temperature Safety Switch (300 °F setpoint) installed
on top of the aluminum boiler section shuts off boiler by
shutting off power to Integrated Boiler Control (IBC). This
fault requires manual reset of casting temperature safety
switch to restart the boiler. Verify that boiler is properly
filled with water before resetting this switch.
Never run cold water into a hot empty boiler.
CONTROLS AND ACCESSORIES
7 - Differential Pressure Air Proving Switch/
Blocked Vent Safety Shutoff
Differential pressure switch monitors air flow by sensing
differential pressure measured in inches of water (" w.c.).
Pressure switch contacts close when draft inducer is
running. Closed switch indicates there is adequate air flow
for combustion. Pressure switch shuts off main burner if
differential pressure is inadequate due to blocked vent pipe,
blocked air intake, blocked boiler sections, or blocked draft
inducer. If pressure switch does not close within 5 minutes
of blower being turned on, control locks out with PURGE
light flashing to indicate pressure switch fault.
8 - Draft Inducer
Draft inducer (blower) provides means for pulling
combustion air into and through the mixer, burner, flue
ways of cast aluminum boiler sections and flue adapter
before being discharged through vent piping to outdoors.
See applicable sections for proper sizing and installation of
combustion air and vent piping in this manual.
9 - Circulator Pump (Optional)
Every forced hot water system requires at least one
circulating pump.
Circulating pump imparts the necessary energy to move
water through closed loop supply and return piping
systems, terminal heating equipment (i.e. finned tube
radiators, etc.) and back through boiler for reheating.
To provide required hot water flow rates, circulator pump
must be properly sized to overcome frictional losses
(usually measured in feet of water, also referred to as
"pump head loss") of supply and return piping systems and
boiler.
The circulator pump is furnished for single zone or zone
valve controlled heating system and should be located on
downstream (i.e., pumping away) side of expansion tank.
For pump controlled system (where there is a circulator for
each zone) circulator provided with boiler can work for one
zone. For more details on piping and circulators, see "Near
Boiler Piping" on page 11.
10 - Drain Valve
Manual drain valve provides means of draining water in
heating system, including boiler and hot water supply and
return piping systems installed above drain valve. This
drain valve is installed in ¾" tapping at bottom of front
boiler section. Any piping installed below elevation of
this drain valve will require additional drain valves to be
installed at low points in piping systems in order to drain
entire system.
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P/N 240010135 Rev. D [04/15/2017]