Dunkirk Q95M-200 Modulating Condensing Boiler - Manual (Page 4)

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3. DHW heating: Target temperature is determined by
adding Parameter 1 to Parameter 33 (default 150°F
and 30°F). Do not change Parameter 1 from factory
default setting of 150°F unless application is specially
engineered for other temperature. DHW heating default
setting is 180°F.
4. High limit operation: If outlet water temperature
exceeds target temperature (or 180°F, whichever is
lower), high limit action occurs. Control module shuts
burner off showing “b 9” followed by “26” on display.
5. DHW operation (if used): Boiler is factory set to
change target outlet water temperature to 180°F on
call for heat from DHW aquastat.
6. Additional Thermal Overrun Protection: High
limit operation shuts down burner when outlet
water temperature exceeds target temperature.
Adverse conditions could cause water temperature
to rise too quickly and overshoot this temperature.
Control’s advanced technology provides protection in
event of thermal overrun. Using its electronics, control
provides two additional levels of overrun protection:
• Level 1: Indication occurs if supply water temperature
reached 183°F. Control displays soft lockout code (“b
9” followed by “18” if on supply or “19” if on return).
Control will not operate burner again until water
temperature dropped 9°F below target temperature.
• Level 2: Lockout occurs if supply water temperature
reaches 200°F or if return water reaches 193°F. Control
will enter hard lockout and display error code (“E”
followed by “18” if on supply or “19” if on return).
NOTICE
Hard lockout requires manually pressing display panel
reset button to restart operation. Service technician
must troubleshoot cause of problem and correct it
before placing boiler back in operation.
Low Water/Low Flow Protection
1.
Boiler is factory equipped with manual reset probe type
low water cutoff.
2. Boiler control uses temperatures sensed at both supply
and return areas of heat exchanger. If flow rate is
too low (temperature difference too high) or either
temperature is too high, control shuts boiler down.
Ensures boiler shutdown in event of low water or low
flow conditions.
Freeze Protection
Do not install boiler in room likely to freeze.
Following boiler control feature provides some protection for boiler
only, not for the system.
Boiler is controlled by microprocessor electronic control that
senses:
• Outlet water temperature,
• Return water temperature,
• Outdoor temperature (when factory supplied, field
installed outdoor sensor is installed).
Information sensed plus input from external limit and
operating controls is used to regulate boiler on/off
operation and will modulate boiler firing rate to more
closely match output to demand.
Electrical Specifications
Boilers require 120 VAC/60 HZ power supply and are not
polarity sensitive.
CONTROL SPECIFICATIONS
Supply voltage 120 Vac/60 hz
Electrical demand 10 VA
Pre-purge timing 10 Seconds
Post-purge timing 15 Seconds
Min. off time, space heating 10.2 Seconds
Pump on after space htg. 0 Minutes
Min. off time, DHW 10.2 Seconds
Pump on after DHW 30.6 Seconds
Line voltage fuse, F1 5 Amp fast-blow
Low voltage fuse, F3 4 Amp slow-blow
Boiler Circulator
• Circulator has sufficient head to handle boiler pressure
drop plus reasonable pressure drop in connecting
piping. See the Installation, Operation and Maintenance
Manual for piping information.
• Boiler control’s internal relay contact is suitable for
handling only the boiler circulator provided.
• Do not wire additional pumps in parallel with boiler
circulator.
• To operate system circulator when boiler circulator is
running, see “Electrical Wiring” section in Installation,
Operation and Maintenance Manual for wiring required.
Boiler Temperature Regulation
Operating temperature (target): Control senses outlet water
temperature and regulates boiler firing rate to achieve
target temperature set by installer using Parameter 4.
Temperature can be set between 120°F and 194°F.
1. Space heating: Target temperature is fixed (equal
to Parameter 4) when outdoor reset is not installed
or calculated as described under “Outdoor Reset
Operation” page 5, when outdoor sensor is connected.
2. Exception: See explanation of “Supply Temperature
Boost” page 5.
3 - OPERATING INFORMATION